10583 lines
326 KiB
C
10583 lines
326 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2018, Joyent, Inc.
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* Copyright (c) 2011, 2019, Delphix. All rights reserved.
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* Copyright (c) 2014, Saso Kiselkov. All rights reserved.
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* Copyright (c) 2017, Nexenta Systems, Inc. All rights reserved.
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* Copyright (c) 2019, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
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* Copyright (c) 2020, George Amanakis. All rights reserved.
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* Copyright (c) 2019, Klara Inc.
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* Copyright (c) 2019, Allan Jude
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* Copyright (c) 2020, The FreeBSD Foundation [1]
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*
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* [1] Portions of this software were developed by Allan Jude
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* under sponsorship from the FreeBSD Foundation.
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*/
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/*
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* DVA-based Adjustable Replacement Cache
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*
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* While much of the theory of operation used here is
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* based on the self-tuning, low overhead replacement cache
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* presented by Megiddo and Modha at FAST 2003, there are some
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* significant differences:
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*
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* 1. The Megiddo and Modha model assumes any page is evictable.
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* Pages in its cache cannot be "locked" into memory. This makes
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* the eviction algorithm simple: evict the last page in the list.
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* This also make the performance characteristics easy to reason
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* about. Our cache is not so simple. At any given moment, some
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* subset of the blocks in the cache are un-evictable because we
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* have handed out a reference to them. Blocks are only evictable
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* when there are no external references active. This makes
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* eviction far more problematic: we choose to evict the evictable
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* blocks that are the "lowest" in the list.
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*
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* There are times when it is not possible to evict the requested
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* space. In these circumstances we are unable to adjust the cache
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* size. To prevent the cache growing unbounded at these times we
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* implement a "cache throttle" that slows the flow of new data
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* into the cache until we can make space available.
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*
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* 2. The Megiddo and Modha model assumes a fixed cache size.
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* Pages are evicted when the cache is full and there is a cache
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* miss. Our model has a variable sized cache. It grows with
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* high use, but also tries to react to memory pressure from the
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* operating system: decreasing its size when system memory is
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* tight.
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*
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* 3. The Megiddo and Modha model assumes a fixed page size. All
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* elements of the cache are therefore exactly the same size. So
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* when adjusting the cache size following a cache miss, its simply
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* a matter of choosing a single page to evict. In our model, we
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* have variable sized cache blocks (ranging from 512 bytes to
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* 128K bytes). We therefore choose a set of blocks to evict to make
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* space for a cache miss that approximates as closely as possible
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* the space used by the new block.
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*
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* See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache"
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* by N. Megiddo & D. Modha, FAST 2003
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*/
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/*
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* The locking model:
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*
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* A new reference to a cache buffer can be obtained in two
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* ways: 1) via a hash table lookup using the DVA as a key,
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* or 2) via one of the ARC lists. The arc_read() interface
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* uses method 1, while the internal ARC algorithms for
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* adjusting the cache use method 2. We therefore provide two
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* types of locks: 1) the hash table lock array, and 2) the
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* ARC list locks.
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*
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* Buffers do not have their own mutexes, rather they rely on the
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* hash table mutexes for the bulk of their protection (i.e. most
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* fields in the arc_buf_hdr_t are protected by these mutexes).
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*
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* buf_hash_find() returns the appropriate mutex (held) when it
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* locates the requested buffer in the hash table. It returns
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* NULL for the mutex if the buffer was not in the table.
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*
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* buf_hash_remove() expects the appropriate hash mutex to be
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* already held before it is invoked.
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*
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* Each ARC state also has a mutex which is used to protect the
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* buffer list associated with the state. When attempting to
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* obtain a hash table lock while holding an ARC list lock you
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* must use: mutex_tryenter() to avoid deadlock. Also note that
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* the active state mutex must be held before the ghost state mutex.
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*
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* It as also possible to register a callback which is run when the
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* arc_meta_limit is reached and no buffers can be safely evicted. In
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* this case the arc user should drop a reference on some arc buffers so
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* they can be reclaimed and the arc_meta_limit honored. For example,
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* when using the ZPL each dentry holds a references on a znode. These
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* dentries must be pruned before the arc buffer holding the znode can
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* be safely evicted.
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*
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* Note that the majority of the performance stats are manipulated
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* with atomic operations.
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*
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* The L2ARC uses the l2ad_mtx on each vdev for the following:
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*
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* - L2ARC buflist creation
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* - L2ARC buflist eviction
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* - L2ARC write completion, which walks L2ARC buflists
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* - ARC header destruction, as it removes from L2ARC buflists
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* - ARC header release, as it removes from L2ARC buflists
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*/
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/*
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* ARC operation:
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*
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* Every block that is in the ARC is tracked by an arc_buf_hdr_t structure.
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* This structure can point either to a block that is still in the cache or to
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* one that is only accessible in an L2 ARC device, or it can provide
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* information about a block that was recently evicted. If a block is
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* only accessible in the L2ARC, then the arc_buf_hdr_t only has enough
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* information to retrieve it from the L2ARC device. This information is
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* stored in the l2arc_buf_hdr_t sub-structure of the arc_buf_hdr_t. A block
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* that is in this state cannot access the data directly.
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*
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* Blocks that are actively being referenced or have not been evicted
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* are cached in the L1ARC. The L1ARC (l1arc_buf_hdr_t) is a structure within
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* the arc_buf_hdr_t that will point to the data block in memory. A block can
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* only be read by a consumer if it has an l1arc_buf_hdr_t. The L1ARC
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* caches data in two ways -- in a list of ARC buffers (arc_buf_t) and
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* also in the arc_buf_hdr_t's private physical data block pointer (b_pabd).
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*
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* The L1ARC's data pointer may or may not be uncompressed. The ARC has the
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* ability to store the physical data (b_pabd) associated with the DVA of the
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* arc_buf_hdr_t. Since the b_pabd is a copy of the on-disk physical block,
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* it will match its on-disk compression characteristics. This behavior can be
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* disabled by setting 'zfs_compressed_arc_enabled' to B_FALSE. When the
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* compressed ARC functionality is disabled, the b_pabd will point to an
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* uncompressed version of the on-disk data.
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*
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* Data in the L1ARC is not accessed by consumers of the ARC directly. Each
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* arc_buf_hdr_t can have multiple ARC buffers (arc_buf_t) which reference it.
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* Each ARC buffer (arc_buf_t) is being actively accessed by a specific ARC
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* consumer. The ARC will provide references to this data and will keep it
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* cached until it is no longer in use. The ARC caches only the L1ARC's physical
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* data block and will evict any arc_buf_t that is no longer referenced. The
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* amount of memory consumed by the arc_buf_ts' data buffers can be seen via the
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* "overhead_size" kstat.
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*
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* Depending on the consumer, an arc_buf_t can be requested in uncompressed or
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* compressed form. The typical case is that consumers will want uncompressed
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* data, and when that happens a new data buffer is allocated where the data is
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* decompressed for them to use. Currently the only consumer who wants
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* compressed arc_buf_t's is "zfs send", when it streams data exactly as it
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* exists on disk. When this happens, the arc_buf_t's data buffer is shared
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* with the arc_buf_hdr_t.
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*
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* Here is a diagram showing an arc_buf_hdr_t referenced by two arc_buf_t's. The
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* first one is owned by a compressed send consumer (and therefore references
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* the same compressed data buffer as the arc_buf_hdr_t) and the second could be
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* used by any other consumer (and has its own uncompressed copy of the data
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* buffer).
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*
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* arc_buf_hdr_t
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* +-----------+
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* | fields |
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* | common to |
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* | L1- and |
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* | L2ARC |
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* +-----------+
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* | l2arc_buf_hdr_t
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* | |
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* +-----------+
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* | l1arc_buf_hdr_t
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* | | arc_buf_t
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* | b_buf +------------>+-----------+ arc_buf_t
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* | b_pabd +-+ |b_next +---->+-----------+
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* +-----------+ | |-----------| |b_next +-->NULL
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* | |b_comp = T | +-----------+
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* | |b_data +-+ |b_comp = F |
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* | +-----------+ | |b_data +-+
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* +->+------+ | +-----------+ |
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* compressed | | | |
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* data | |<--------------+ | uncompressed
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* +------+ compressed, | data
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* shared +-->+------+
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* data | |
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* | |
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* +------+
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*
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* When a consumer reads a block, the ARC must first look to see if the
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* arc_buf_hdr_t is cached. If the hdr is cached then the ARC allocates a new
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* arc_buf_t and either copies uncompressed data into a new data buffer from an
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* existing uncompressed arc_buf_t, decompresses the hdr's b_pabd buffer into a
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* new data buffer, or shares the hdr's b_pabd buffer, depending on whether the
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* hdr is compressed and the desired compression characteristics of the
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* arc_buf_t consumer. If the arc_buf_t ends up sharing data with the
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* arc_buf_hdr_t and both of them are uncompressed then the arc_buf_t must be
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* the last buffer in the hdr's b_buf list, however a shared compressed buf can
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* be anywhere in the hdr's list.
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*
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* The diagram below shows an example of an uncompressed ARC hdr that is
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* sharing its data with an arc_buf_t (note that the shared uncompressed buf is
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* the last element in the buf list):
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*
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* arc_buf_hdr_t
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* +-----------+
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* | |
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* | |
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* | |
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* +-----------+
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* l2arc_buf_hdr_t| |
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* | |
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* +-----------+
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* l1arc_buf_hdr_t| |
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* | | arc_buf_t (shared)
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* | b_buf +------------>+---------+ arc_buf_t
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* | | |b_next +---->+---------+
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* | b_pabd +-+ |---------| |b_next +-->NULL
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* +-----------+ | | | +---------+
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* | |b_data +-+ | |
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* | +---------+ | |b_data +-+
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* +->+------+ | +---------+ |
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* | | | |
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* uncompressed | | | |
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* data +------+ | |
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* ^ +->+------+ |
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* | uncompressed | | |
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* | data | | |
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* | +------+ |
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* +---------------------------------+
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*
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* Writing to the ARC requires that the ARC first discard the hdr's b_pabd
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* since the physical block is about to be rewritten. The new data contents
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* will be contained in the arc_buf_t. As the I/O pipeline performs the write,
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* it may compress the data before writing it to disk. The ARC will be called
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* with the transformed data and will bcopy the transformed on-disk block into
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* a newly allocated b_pabd. Writes are always done into buffers which have
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* either been loaned (and hence are new and don't have other readers) or
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* buffers which have been released (and hence have their own hdr, if there
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* were originally other readers of the buf's original hdr). This ensures that
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* the ARC only needs to update a single buf and its hdr after a write occurs.
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*
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* When the L2ARC is in use, it will also take advantage of the b_pabd. The
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* L2ARC will always write the contents of b_pabd to the L2ARC. This means
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* that when compressed ARC is enabled that the L2ARC blocks are identical
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* to the on-disk block in the main data pool. This provides a significant
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* advantage since the ARC can leverage the bp's checksum when reading from the
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* L2ARC to determine if the contents are valid. However, if the compressed
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* ARC is disabled, then the L2ARC's block must be transformed to look
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* like the physical block in the main data pool before comparing the
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* checksum and determining its validity.
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*
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* The L1ARC has a slightly different system for storing encrypted data.
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* Raw (encrypted + possibly compressed) data has a few subtle differences from
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* data that is just compressed. The biggest difference is that it is not
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* possible to decrypt encrypted data (or vice-versa) if the keys aren't loaded.
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* The other difference is that encryption cannot be treated as a suggestion.
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* If a caller would prefer compressed data, but they actually wind up with
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* uncompressed data the worst thing that could happen is there might be a
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* performance hit. If the caller requests encrypted data, however, we must be
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* sure they actually get it or else secret information could be leaked. Raw
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* data is stored in hdr->b_crypt_hdr.b_rabd. An encrypted header, therefore,
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* may have both an encrypted version and a decrypted version of its data at
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* once. When a caller needs a raw arc_buf_t, it is allocated and the data is
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* copied out of this header. To avoid complications with b_pabd, raw buffers
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* cannot be shared.
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*/
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#include <sys/spa.h>
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#include <sys/zio.h>
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#include <sys/spa_impl.h>
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#include <sys/zio_compress.h>
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#include <sys/zio_checksum.h>
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#include <sys/zfs_context.h>
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#include <sys/arc.h>
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#include <sys/zfs_refcount.h>
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#include <sys/vdev.h>
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#include <sys/vdev_impl.h>
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#include <sys/dsl_pool.h>
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#include <sys/zio_checksum.h>
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#include <sys/multilist.h>
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#include <sys/abd.h>
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#include <sys/zil.h>
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#include <sys/fm/fs/zfs.h>
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#include <sys/callb.h>
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#include <sys/kstat.h>
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#include <sys/zthr.h>
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#include <zfs_fletcher.h>
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#include <sys/arc_impl.h>
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#include <sys/trace_zfs.h>
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#include <sys/aggsum.h>
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#include <cityhash.h>
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#include <sys/vdev_trim.h>
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#ifndef _KERNEL
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/* set with ZFS_DEBUG=watch, to enable watchpoints on frozen buffers */
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boolean_t arc_watch = B_FALSE;
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#endif
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/*
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* This thread's job is to keep enough free memory in the system, by
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* calling arc_kmem_reap_soon() plus arc_reduce_target_size(), which improves
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* arc_available_memory().
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*/
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static zthr_t *arc_reap_zthr;
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/*
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* This thread's job is to keep arc_size under arc_c, by calling
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* arc_evict(), which improves arc_is_overflowing().
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*/
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static zthr_t *arc_evict_zthr;
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static kmutex_t arc_evict_lock;
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static boolean_t arc_evict_needed = B_FALSE;
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/*
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* Count of bytes evicted since boot.
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*/
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static uint64_t arc_evict_count;
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/*
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* List of arc_evict_waiter_t's, representing threads waiting for the
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* arc_evict_count to reach specific values.
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*/
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static list_t arc_evict_waiters;
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/*
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* When arc_is_overflowing(), arc_get_data_impl() waits for this percent of
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* the requested amount of data to be evicted. For example, by default for
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* every 2KB that's evicted, 1KB of it may be "reused" by a new allocation.
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* Since this is above 100%, it ensures that progress is made towards getting
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* arc_size under arc_c. Since this is finite, it ensures that allocations
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* can still happen, even during the potentially long time that arc_size is
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* more than arc_c.
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*/
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int zfs_arc_eviction_pct = 200;
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/*
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* The number of headers to evict in arc_evict_state_impl() before
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* dropping the sublist lock and evicting from another sublist. A lower
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* value means we're more likely to evict the "correct" header (i.e. the
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* oldest header in the arc state), but comes with higher overhead
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* (i.e. more invocations of arc_evict_state_impl()).
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*/
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int zfs_arc_evict_batch_limit = 10;
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/* number of seconds before growing cache again */
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int arc_grow_retry = 5;
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/*
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* Minimum time between calls to arc_kmem_reap_soon().
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*/
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int arc_kmem_cache_reap_retry_ms = 1000;
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/* shift of arc_c for calculating overflow limit in arc_get_data_impl */
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int zfs_arc_overflow_shift = 8;
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/* shift of arc_c for calculating both min and max arc_p */
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int arc_p_min_shift = 4;
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/* log2(fraction of arc to reclaim) */
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int arc_shrink_shift = 7;
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/* percent of pagecache to reclaim arc to */
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#ifdef _KERNEL
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uint_t zfs_arc_pc_percent = 0;
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#endif
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/*
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* log2(fraction of ARC which must be free to allow growing).
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* I.e. If there is less than arc_c >> arc_no_grow_shift free memory,
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* when reading a new block into the ARC, we will evict an equal-sized block
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* from the ARC.
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*
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* This must be less than arc_shrink_shift, so that when we shrink the ARC,
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* we will still not allow it to grow.
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*/
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int arc_no_grow_shift = 5;
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/*
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* minimum lifespan of a prefetch block in clock ticks
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* (initialized in arc_init())
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*/
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static int arc_min_prefetch_ms;
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static int arc_min_prescient_prefetch_ms;
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/*
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* If this percent of memory is free, don't throttle.
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*/
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int arc_lotsfree_percent = 10;
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/*
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* The arc has filled available memory and has now warmed up.
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*/
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boolean_t arc_warm;
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/*
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* These tunables are for performance analysis.
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*/
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unsigned long zfs_arc_max = 0;
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unsigned long zfs_arc_min = 0;
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unsigned long zfs_arc_meta_limit = 0;
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unsigned long zfs_arc_meta_min = 0;
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unsigned long zfs_arc_dnode_limit = 0;
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unsigned long zfs_arc_dnode_reduce_percent = 10;
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int zfs_arc_grow_retry = 0;
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int zfs_arc_shrink_shift = 0;
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int zfs_arc_p_min_shift = 0;
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int zfs_arc_average_blocksize = 8 * 1024; /* 8KB */
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/*
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* ARC dirty data constraints for arc_tempreserve_space() throttle.
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*/
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unsigned long zfs_arc_dirty_limit_percent = 50; /* total dirty data limit */
|
|
unsigned long zfs_arc_anon_limit_percent = 25; /* anon block dirty limit */
|
|
unsigned long zfs_arc_pool_dirty_percent = 20; /* each pool's anon allowance */
|
|
|
|
/*
|
|
* Enable or disable compressed arc buffers.
|
|
*/
|
|
int zfs_compressed_arc_enabled = B_TRUE;
|
|
|
|
/*
|
|
* ARC will evict meta buffers that exceed arc_meta_limit. This
|
|
* tunable make arc_meta_limit adjustable for different workloads.
|
|
*/
|
|
unsigned long zfs_arc_meta_limit_percent = 75;
|
|
|
|
/*
|
|
* Percentage that can be consumed by dnodes of ARC meta buffers.
|
|
*/
|
|
unsigned long zfs_arc_dnode_limit_percent = 10;
|
|
|
|
/*
|
|
* These tunables are Linux specific
|
|
*/
|
|
unsigned long zfs_arc_sys_free = 0;
|
|
int zfs_arc_min_prefetch_ms = 0;
|
|
int zfs_arc_min_prescient_prefetch_ms = 0;
|
|
int zfs_arc_p_dampener_disable = 1;
|
|
int zfs_arc_meta_prune = 10000;
|
|
int zfs_arc_meta_strategy = ARC_STRATEGY_META_BALANCED;
|
|
int zfs_arc_meta_adjust_restarts = 4096;
|
|
int zfs_arc_lotsfree_percent = 10;
|
|
|
|
/* The 6 states: */
|
|
arc_state_t ARC_anon;
|
|
arc_state_t ARC_mru;
|
|
arc_state_t ARC_mru_ghost;
|
|
arc_state_t ARC_mfu;
|
|
arc_state_t ARC_mfu_ghost;
|
|
arc_state_t ARC_l2c_only;
|
|
|
|
arc_stats_t arc_stats = {
|
|
{ "hits", KSTAT_DATA_UINT64 },
|
|
{ "misses", KSTAT_DATA_UINT64 },
|
|
{ "demand_data_hits", KSTAT_DATA_UINT64 },
|
|
{ "demand_data_misses", KSTAT_DATA_UINT64 },
|
|
{ "demand_metadata_hits", KSTAT_DATA_UINT64 },
|
|
{ "demand_metadata_misses", KSTAT_DATA_UINT64 },
|
|
{ "prefetch_data_hits", KSTAT_DATA_UINT64 },
|
|
{ "prefetch_data_misses", KSTAT_DATA_UINT64 },
|
|
{ "prefetch_metadata_hits", KSTAT_DATA_UINT64 },
|
|
{ "prefetch_metadata_misses", KSTAT_DATA_UINT64 },
|
|
{ "mru_hits", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_hits", KSTAT_DATA_UINT64 },
|
|
{ "mfu_hits", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_hits", KSTAT_DATA_UINT64 },
|
|
{ "deleted", KSTAT_DATA_UINT64 },
|
|
{ "mutex_miss", KSTAT_DATA_UINT64 },
|
|
{ "access_skip", KSTAT_DATA_UINT64 },
|
|
{ "evict_skip", KSTAT_DATA_UINT64 },
|
|
{ "evict_not_enough", KSTAT_DATA_UINT64 },
|
|
{ "evict_l2_cached", KSTAT_DATA_UINT64 },
|
|
{ "evict_l2_eligible", KSTAT_DATA_UINT64 },
|
|
{ "evict_l2_ineligible", KSTAT_DATA_UINT64 },
|
|
{ "evict_l2_skip", KSTAT_DATA_UINT64 },
|
|
{ "hash_elements", KSTAT_DATA_UINT64 },
|
|
{ "hash_elements_max", KSTAT_DATA_UINT64 },
|
|
{ "hash_collisions", KSTAT_DATA_UINT64 },
|
|
{ "hash_chains", KSTAT_DATA_UINT64 },
|
|
{ "hash_chain_max", KSTAT_DATA_UINT64 },
|
|
{ "p", KSTAT_DATA_UINT64 },
|
|
{ "c", KSTAT_DATA_UINT64 },
|
|
{ "c_min", KSTAT_DATA_UINT64 },
|
|
{ "c_max", KSTAT_DATA_UINT64 },
|
|
{ "size", KSTAT_DATA_UINT64 },
|
|
{ "compressed_size", KSTAT_DATA_UINT64 },
|
|
{ "uncompressed_size", KSTAT_DATA_UINT64 },
|
|
{ "overhead_size", KSTAT_DATA_UINT64 },
|
|
{ "hdr_size", KSTAT_DATA_UINT64 },
|
|
{ "data_size", KSTAT_DATA_UINT64 },
|
|
{ "metadata_size", KSTAT_DATA_UINT64 },
|
|
{ "dbuf_size", KSTAT_DATA_UINT64 },
|
|
{ "dnode_size", KSTAT_DATA_UINT64 },
|
|
{ "bonus_size", KSTAT_DATA_UINT64 },
|
|
#if defined(COMPAT_FREEBSD11)
|
|
{ "other_size", KSTAT_DATA_UINT64 },
|
|
#endif
|
|
{ "anon_size", KSTAT_DATA_UINT64 },
|
|
{ "anon_evictable_data", KSTAT_DATA_UINT64 },
|
|
{ "anon_evictable_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mru_size", KSTAT_DATA_UINT64 },
|
|
{ "mru_evictable_data", KSTAT_DATA_UINT64 },
|
|
{ "mru_evictable_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_size", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_evictable_data", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_evictable_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mfu_size", KSTAT_DATA_UINT64 },
|
|
{ "mfu_evictable_data", KSTAT_DATA_UINT64 },
|
|
{ "mfu_evictable_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_size", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_evictable_data", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_evictable_metadata", KSTAT_DATA_UINT64 },
|
|
{ "l2_hits", KSTAT_DATA_UINT64 },
|
|
{ "l2_misses", KSTAT_DATA_UINT64 },
|
|
{ "l2_feeds", KSTAT_DATA_UINT64 },
|
|
{ "l2_rw_clash", KSTAT_DATA_UINT64 },
|
|
{ "l2_read_bytes", KSTAT_DATA_UINT64 },
|
|
{ "l2_write_bytes", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_sent", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_done", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_error", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_lock_retry", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_lock_retry", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_reading", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_l1cached", KSTAT_DATA_UINT64 },
|
|
{ "l2_free_on_write", KSTAT_DATA_UINT64 },
|
|
{ "l2_abort_lowmem", KSTAT_DATA_UINT64 },
|
|
{ "l2_cksum_bad", KSTAT_DATA_UINT64 },
|
|
{ "l2_io_error", KSTAT_DATA_UINT64 },
|
|
{ "l2_size", KSTAT_DATA_UINT64 },
|
|
{ "l2_asize", KSTAT_DATA_UINT64 },
|
|
{ "l2_hdr_size", KSTAT_DATA_UINT64 },
|
|
{ "l2_log_blk_writes", KSTAT_DATA_UINT64 },
|
|
{ "l2_log_blk_avg_asize", KSTAT_DATA_UINT64 },
|
|
{ "l2_log_blk_asize", KSTAT_DATA_UINT64 },
|
|
{ "l2_log_blk_count", KSTAT_DATA_UINT64 },
|
|
{ "l2_data_to_meta_ratio", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_success", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_unsupported", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_io_errors", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_dh_errors", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_cksum_lb_errors", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_lowmem", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_size", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_asize", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_bufs", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_bufs_precached", KSTAT_DATA_UINT64 },
|
|
{ "l2_rebuild_log_blks", KSTAT_DATA_UINT64 },
|
|
{ "memory_throttle_count", KSTAT_DATA_UINT64 },
|
|
{ "memory_direct_count", KSTAT_DATA_UINT64 },
|
|
{ "memory_indirect_count", KSTAT_DATA_UINT64 },
|
|
{ "memory_all_bytes", KSTAT_DATA_UINT64 },
|
|
{ "memory_free_bytes", KSTAT_DATA_UINT64 },
|
|
{ "memory_available_bytes", KSTAT_DATA_INT64 },
|
|
{ "arc_no_grow", KSTAT_DATA_UINT64 },
|
|
{ "arc_tempreserve", KSTAT_DATA_UINT64 },
|
|
{ "arc_loaned_bytes", KSTAT_DATA_UINT64 },
|
|
{ "arc_prune", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_used", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_limit", KSTAT_DATA_UINT64 },
|
|
{ "arc_dnode_limit", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_max", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_min", KSTAT_DATA_UINT64 },
|
|
{ "async_upgrade_sync", KSTAT_DATA_UINT64 },
|
|
{ "demand_hit_predictive_prefetch", KSTAT_DATA_UINT64 },
|
|
{ "demand_hit_prescient_prefetch", KSTAT_DATA_UINT64 },
|
|
{ "arc_need_free", KSTAT_DATA_UINT64 },
|
|
{ "arc_sys_free", KSTAT_DATA_UINT64 },
|
|
{ "arc_raw_size", KSTAT_DATA_UINT64 },
|
|
{ "cached_only_in_progress", KSTAT_DATA_UINT64 },
|
|
{ "abd_chunk_waste_size", KSTAT_DATA_UINT64 },
|
|
};
|
|
|
|
#define ARCSTAT_MAX(stat, val) { \
|
|
uint64_t m; \
|
|
while ((val) > (m = arc_stats.stat.value.ui64) && \
|
|
(m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \
|
|
continue; \
|
|
}
|
|
|
|
#define ARCSTAT_MAXSTAT(stat) \
|
|
ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64)
|
|
|
|
/*
|
|
* We define a macro to allow ARC hits/misses to be easily broken down by
|
|
* two separate conditions, giving a total of four different subtypes for
|
|
* each of hits and misses (so eight statistics total).
|
|
*/
|
|
#define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \
|
|
if (cond1) { \
|
|
if (cond2) { \
|
|
ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \
|
|
} else { \
|
|
ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \
|
|
} \
|
|
} else { \
|
|
if (cond2) { \
|
|
ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \
|
|
} else { \
|
|
ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\
|
|
} \
|
|
}
|
|
|
|
/*
|
|
* This macro allows us to use kstats as floating averages. Each time we
|
|
* update this kstat, we first factor it and the update value by
|
|
* ARCSTAT_AVG_FACTOR to shrink the new value's contribution to the overall
|
|
* average. This macro assumes that integer loads and stores are atomic, but
|
|
* is not safe for multiple writers updating the kstat in parallel (only the
|
|
* last writer's update will remain).
|
|
*/
|
|
#define ARCSTAT_F_AVG_FACTOR 3
|
|
#define ARCSTAT_F_AVG(stat, value) \
|
|
do { \
|
|
uint64_t x = ARCSTAT(stat); \
|
|
x = x - x / ARCSTAT_F_AVG_FACTOR + \
|
|
(value) / ARCSTAT_F_AVG_FACTOR; \
|
|
ARCSTAT(stat) = x; \
|
|
_NOTE(CONSTCOND) \
|
|
} while (0)
|
|
|
|
kstat_t *arc_ksp;
|
|
static arc_state_t *arc_anon;
|
|
static arc_state_t *arc_mru_ghost;
|
|
static arc_state_t *arc_mfu_ghost;
|
|
static arc_state_t *arc_l2c_only;
|
|
|
|
arc_state_t *arc_mru;
|
|
arc_state_t *arc_mfu;
|
|
|
|
/*
|
|
* There are several ARC variables that are critical to export as kstats --
|
|
* but we don't want to have to grovel around in the kstat whenever we wish to
|
|
* manipulate them. For these variables, we therefore define them to be in
|
|
* terms of the statistic variable. This assures that we are not introducing
|
|
* the possibility of inconsistency by having shadow copies of the variables,
|
|
* while still allowing the code to be readable.
|
|
*/
|
|
#define arc_tempreserve ARCSTAT(arcstat_tempreserve)
|
|
#define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes)
|
|
#define arc_meta_limit ARCSTAT(arcstat_meta_limit) /* max size for metadata */
|
|
/* max size for dnodes */
|
|
#define arc_dnode_size_limit ARCSTAT(arcstat_dnode_limit)
|
|
#define arc_meta_min ARCSTAT(arcstat_meta_min) /* min size for metadata */
|
|
#define arc_meta_max ARCSTAT(arcstat_meta_max) /* max size of metadata */
|
|
#define arc_need_free ARCSTAT(arcstat_need_free) /* waiting to be evicted */
|
|
|
|
/* size of all b_rabd's in entire arc */
|
|
#define arc_raw_size ARCSTAT(arcstat_raw_size)
|
|
/* compressed size of entire arc */
|
|
#define arc_compressed_size ARCSTAT(arcstat_compressed_size)
|
|
/* uncompressed size of entire arc */
|
|
#define arc_uncompressed_size ARCSTAT(arcstat_uncompressed_size)
|
|
/* number of bytes in the arc from arc_buf_t's */
|
|
#define arc_overhead_size ARCSTAT(arcstat_overhead_size)
|
|
|
|
/*
|
|
* There are also some ARC variables that we want to export, but that are
|
|
* updated so often that having the canonical representation be the statistic
|
|
* variable causes a performance bottleneck. We want to use aggsum_t's for these
|
|
* instead, but still be able to export the kstat in the same way as before.
|
|
* The solution is to always use the aggsum version, except in the kstat update
|
|
* callback.
|
|
*/
|
|
aggsum_t arc_size;
|
|
aggsum_t arc_meta_used;
|
|
aggsum_t astat_data_size;
|
|
aggsum_t astat_metadata_size;
|
|
aggsum_t astat_dbuf_size;
|
|
aggsum_t astat_dnode_size;
|
|
aggsum_t astat_bonus_size;
|
|
aggsum_t astat_hdr_size;
|
|
aggsum_t astat_l2_hdr_size;
|
|
aggsum_t astat_abd_chunk_waste_size;
|
|
|
|
hrtime_t arc_growtime;
|
|
list_t arc_prune_list;
|
|
kmutex_t arc_prune_mtx;
|
|
taskq_t *arc_prune_taskq;
|
|
|
|
#define GHOST_STATE(state) \
|
|
((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \
|
|
(state) == arc_l2c_only)
|
|
|
|
#define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_FLAG_IN_HASH_TABLE)
|
|
#define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS)
|
|
#define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_FLAG_IO_ERROR)
|
|
#define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_FLAG_PREFETCH)
|
|
#define HDR_PRESCIENT_PREFETCH(hdr) \
|
|
((hdr)->b_flags & ARC_FLAG_PRESCIENT_PREFETCH)
|
|
#define HDR_COMPRESSION_ENABLED(hdr) \
|
|
((hdr)->b_flags & ARC_FLAG_COMPRESSED_ARC)
|
|
|
|
#define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_FLAG_L2CACHE)
|
|
#define HDR_L2_READING(hdr) \
|
|
(((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) && \
|
|
((hdr)->b_flags & ARC_FLAG_HAS_L2HDR))
|
|
#define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITING)
|
|
#define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_FLAG_L2_EVICTED)
|
|
#define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITE_HEAD)
|
|
#define HDR_PROTECTED(hdr) ((hdr)->b_flags & ARC_FLAG_PROTECTED)
|
|
#define HDR_NOAUTH(hdr) ((hdr)->b_flags & ARC_FLAG_NOAUTH)
|
|
#define HDR_SHARED_DATA(hdr) ((hdr)->b_flags & ARC_FLAG_SHARED_DATA)
|
|
|
|
#define HDR_ISTYPE_METADATA(hdr) \
|
|
((hdr)->b_flags & ARC_FLAG_BUFC_METADATA)
|
|
#define HDR_ISTYPE_DATA(hdr) (!HDR_ISTYPE_METADATA(hdr))
|
|
|
|
#define HDR_HAS_L1HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L1HDR)
|
|
#define HDR_HAS_L2HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR)
|
|
#define HDR_HAS_RABD(hdr) \
|
|
(HDR_HAS_L1HDR(hdr) && HDR_PROTECTED(hdr) && \
|
|
(hdr)->b_crypt_hdr.b_rabd != NULL)
|
|
#define HDR_ENCRYPTED(hdr) \
|
|
(HDR_PROTECTED(hdr) && DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot))
|
|
#define HDR_AUTHENTICATED(hdr) \
|
|
(HDR_PROTECTED(hdr) && !DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot))
|
|
|
|
/* For storing compression mode in b_flags */
|
|
#define HDR_COMPRESS_OFFSET (highbit64(ARC_FLAG_COMPRESS_0) - 1)
|
|
|
|
#define HDR_GET_COMPRESS(hdr) ((enum zio_compress)BF32_GET((hdr)->b_flags, \
|
|
HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS))
|
|
#define HDR_SET_COMPRESS(hdr, cmp) BF32_SET((hdr)->b_flags, \
|
|
HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS, (cmp));
|
|
|
|
#define ARC_BUF_LAST(buf) ((buf)->b_next == NULL)
|
|
#define ARC_BUF_SHARED(buf) ((buf)->b_flags & ARC_BUF_FLAG_SHARED)
|
|
#define ARC_BUF_COMPRESSED(buf) ((buf)->b_flags & ARC_BUF_FLAG_COMPRESSED)
|
|
#define ARC_BUF_ENCRYPTED(buf) ((buf)->b_flags & ARC_BUF_FLAG_ENCRYPTED)
|
|
|
|
/*
|
|
* Other sizes
|
|
*/
|
|
|
|
#define HDR_FULL_CRYPT_SIZE ((int64_t)sizeof (arc_buf_hdr_t))
|
|
#define HDR_FULL_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_crypt_hdr))
|
|
#define HDR_L2ONLY_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_l1hdr))
|
|
|
|
/*
|
|
* Hash table routines
|
|
*/
|
|
|
|
#define HT_LOCK_ALIGN 64
|
|
#define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN)))
|
|
|
|
struct ht_lock {
|
|
kmutex_t ht_lock;
|
|
#ifdef _KERNEL
|
|
unsigned char pad[HT_LOCK_PAD];
|
|
#endif
|
|
};
|
|
|
|
#define BUF_LOCKS 8192
|
|
typedef struct buf_hash_table {
|
|
uint64_t ht_mask;
|
|
arc_buf_hdr_t **ht_table;
|
|
struct ht_lock ht_locks[BUF_LOCKS];
|
|
} buf_hash_table_t;
|
|
|
|
static buf_hash_table_t buf_hash_table;
|
|
|
|
#define BUF_HASH_INDEX(spa, dva, birth) \
|
|
(buf_hash(spa, dva, birth) & buf_hash_table.ht_mask)
|
|
#define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)])
|
|
#define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock))
|
|
#define HDR_LOCK(hdr) \
|
|
(BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth)))
|
|
|
|
uint64_t zfs_crc64_table[256];
|
|
|
|
/*
|
|
* Level 2 ARC
|
|
*/
|
|
|
|
#define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */
|
|
#define L2ARC_HEADROOM 2 /* num of writes */
|
|
|
|
/*
|
|
* If we discover during ARC scan any buffers to be compressed, we boost
|
|
* our headroom for the next scanning cycle by this percentage multiple.
|
|
*/
|
|
#define L2ARC_HEADROOM_BOOST 200
|
|
#define L2ARC_FEED_SECS 1 /* caching interval secs */
|
|
#define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */
|
|
|
|
/*
|
|
* We can feed L2ARC from two states of ARC buffers, mru and mfu,
|
|
* and each of the state has two types: data and metadata.
|
|
*/
|
|
#define L2ARC_FEED_TYPES 4
|
|
|
|
#define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent)
|
|
#define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done)
|
|
|
|
/* L2ARC Performance Tunables */
|
|
unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */
|
|
unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */
|
|
unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */
|
|
unsigned long l2arc_headroom_boost = L2ARC_HEADROOM_BOOST;
|
|
unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */
|
|
unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */
|
|
int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */
|
|
int l2arc_feed_again = B_TRUE; /* turbo warmup */
|
|
int l2arc_norw = B_FALSE; /* no reads during writes */
|
|
int l2arc_meta_percent = 33; /* limit on headers size */
|
|
|
|
/*
|
|
* L2ARC Internals
|
|
*/
|
|
static list_t L2ARC_dev_list; /* device list */
|
|
static list_t *l2arc_dev_list; /* device list pointer */
|
|
static kmutex_t l2arc_dev_mtx; /* device list mutex */
|
|
static l2arc_dev_t *l2arc_dev_last; /* last device used */
|
|
static list_t L2ARC_free_on_write; /* free after write buf list */
|
|
static list_t *l2arc_free_on_write; /* free after write list ptr */
|
|
static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */
|
|
static uint64_t l2arc_ndev; /* number of devices */
|
|
|
|
typedef struct l2arc_read_callback {
|
|
arc_buf_hdr_t *l2rcb_hdr; /* read header */
|
|
blkptr_t l2rcb_bp; /* original blkptr */
|
|
zbookmark_phys_t l2rcb_zb; /* original bookmark */
|
|
int l2rcb_flags; /* original flags */
|
|
abd_t *l2rcb_abd; /* temporary buffer */
|
|
} l2arc_read_callback_t;
|
|
|
|
typedef struct l2arc_data_free {
|
|
/* protected by l2arc_free_on_write_mtx */
|
|
abd_t *l2df_abd;
|
|
size_t l2df_size;
|
|
arc_buf_contents_t l2df_type;
|
|
list_node_t l2df_list_node;
|
|
} l2arc_data_free_t;
|
|
|
|
typedef enum arc_fill_flags {
|
|
ARC_FILL_LOCKED = 1 << 0, /* hdr lock is held */
|
|
ARC_FILL_COMPRESSED = 1 << 1, /* fill with compressed data */
|
|
ARC_FILL_ENCRYPTED = 1 << 2, /* fill with encrypted data */
|
|
ARC_FILL_NOAUTH = 1 << 3, /* don't attempt to authenticate */
|
|
ARC_FILL_IN_PLACE = 1 << 4 /* fill in place (special case) */
|
|
} arc_fill_flags_t;
|
|
|
|
static kmutex_t l2arc_feed_thr_lock;
|
|
static kcondvar_t l2arc_feed_thr_cv;
|
|
static uint8_t l2arc_thread_exit;
|
|
|
|
static kmutex_t l2arc_rebuild_thr_lock;
|
|
static kcondvar_t l2arc_rebuild_thr_cv;
|
|
|
|
enum arc_hdr_alloc_flags {
|
|
ARC_HDR_ALLOC_RDATA = 0x1,
|
|
ARC_HDR_DO_ADAPT = 0x2,
|
|
};
|
|
|
|
|
|
static abd_t *arc_get_data_abd(arc_buf_hdr_t *, uint64_t, void *, boolean_t);
|
|
static void *arc_get_data_buf(arc_buf_hdr_t *, uint64_t, void *);
|
|
static void arc_get_data_impl(arc_buf_hdr_t *, uint64_t, void *, boolean_t);
|
|
static void arc_free_data_abd(arc_buf_hdr_t *, abd_t *, uint64_t, void *);
|
|
static void arc_free_data_buf(arc_buf_hdr_t *, void *, uint64_t, void *);
|
|
static void arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag);
|
|
static void arc_hdr_free_abd(arc_buf_hdr_t *, boolean_t);
|
|
static void arc_hdr_alloc_abd(arc_buf_hdr_t *, int);
|
|
static void arc_access(arc_buf_hdr_t *, kmutex_t *);
|
|
static void arc_buf_watch(arc_buf_t *);
|
|
|
|
static arc_buf_contents_t arc_buf_type(arc_buf_hdr_t *);
|
|
static uint32_t arc_bufc_to_flags(arc_buf_contents_t);
|
|
static inline void arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags);
|
|
static inline void arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags);
|
|
|
|
static boolean_t l2arc_write_eligible(uint64_t, arc_buf_hdr_t *);
|
|
static void l2arc_read_done(zio_t *);
|
|
static void l2arc_do_free_on_write(void);
|
|
|
|
/*
|
|
* L2ARC TRIM
|
|
* l2arc_trim_ahead : A ZFS module parameter that controls how much ahead of
|
|
* the current write size (l2arc_write_max) we should TRIM if we
|
|
* have filled the device. It is defined as a percentage of the
|
|
* write size. If set to 100 we trim twice the space required to
|
|
* accommodate upcoming writes. A minimum of 64MB will be trimmed.
|
|
* It also enables TRIM of the whole L2ARC device upon creation or
|
|
* addition to an existing pool or if the header of the device is
|
|
* invalid upon importing a pool or onlining a cache device. The
|
|
* default is 0, which disables TRIM on L2ARC altogether as it can
|
|
* put significant stress on the underlying storage devices. This
|
|
* will vary depending of how well the specific device handles
|
|
* these commands.
|
|
*/
|
|
unsigned long l2arc_trim_ahead = 0;
|
|
|
|
/*
|
|
* Performance tuning of L2ARC persistence:
|
|
*
|
|
* l2arc_rebuild_enabled : A ZFS module parameter that controls whether adding
|
|
* an L2ARC device (either at pool import or later) will attempt
|
|
* to rebuild L2ARC buffer contents.
|
|
* l2arc_rebuild_blocks_min_l2size : A ZFS module parameter that controls
|
|
* whether log blocks are written to the L2ARC device. If the L2ARC
|
|
* device is less than 1GB, the amount of data l2arc_evict()
|
|
* evicts is significant compared to the amount of restored L2ARC
|
|
* data. In this case do not write log blocks in L2ARC in order
|
|
* not to waste space.
|
|
*/
|
|
int l2arc_rebuild_enabled = B_TRUE;
|
|
unsigned long l2arc_rebuild_blocks_min_l2size = 1024 * 1024 * 1024;
|
|
|
|
/* L2ARC persistence rebuild control routines. */
|
|
void l2arc_rebuild_vdev(vdev_t *vd, boolean_t reopen);
|
|
static void l2arc_dev_rebuild_thread(void *arg);
|
|
static int l2arc_rebuild(l2arc_dev_t *dev);
|
|
|
|
/* L2ARC persistence read I/O routines. */
|
|
static int l2arc_dev_hdr_read(l2arc_dev_t *dev);
|
|
static int l2arc_log_blk_read(l2arc_dev_t *dev,
|
|
const l2arc_log_blkptr_t *this_lp, const l2arc_log_blkptr_t *next_lp,
|
|
l2arc_log_blk_phys_t *this_lb, l2arc_log_blk_phys_t *next_lb,
|
|
zio_t *this_io, zio_t **next_io);
|
|
static zio_t *l2arc_log_blk_fetch(vdev_t *vd,
|
|
const l2arc_log_blkptr_t *lp, l2arc_log_blk_phys_t *lb);
|
|
static void l2arc_log_blk_fetch_abort(zio_t *zio);
|
|
|
|
/* L2ARC persistence block restoration routines. */
|
|
static void l2arc_log_blk_restore(l2arc_dev_t *dev,
|
|
const l2arc_log_blk_phys_t *lb, uint64_t lb_asize, uint64_t lb_daddr);
|
|
static void l2arc_hdr_restore(const l2arc_log_ent_phys_t *le,
|
|
l2arc_dev_t *dev);
|
|
|
|
/* L2ARC persistence write I/O routines. */
|
|
static void l2arc_log_blk_commit(l2arc_dev_t *dev, zio_t *pio,
|
|
l2arc_write_callback_t *cb);
|
|
|
|
/* L2ARC persistence auxiliary routines. */
|
|
boolean_t l2arc_log_blkptr_valid(l2arc_dev_t *dev,
|
|
const l2arc_log_blkptr_t *lbp);
|
|
static boolean_t l2arc_log_blk_insert(l2arc_dev_t *dev,
|
|
const arc_buf_hdr_t *ab);
|
|
boolean_t l2arc_range_check_overlap(uint64_t bottom,
|
|
uint64_t top, uint64_t check);
|
|
static void l2arc_blk_fetch_done(zio_t *zio);
|
|
static inline uint64_t
|
|
l2arc_log_blk_overhead(uint64_t write_sz, l2arc_dev_t *dev);
|
|
|
|
/*
|
|
* We use Cityhash for this. It's fast, and has good hash properties without
|
|
* requiring any large static buffers.
|
|
*/
|
|
static uint64_t
|
|
buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth)
|
|
{
|
|
return (cityhash4(spa, dva->dva_word[0], dva->dva_word[1], birth));
|
|
}
|
|
|
|
#define HDR_EMPTY(hdr) \
|
|
((hdr)->b_dva.dva_word[0] == 0 && \
|
|
(hdr)->b_dva.dva_word[1] == 0)
|
|
|
|
#define HDR_EMPTY_OR_LOCKED(hdr) \
|
|
(HDR_EMPTY(hdr) || MUTEX_HELD(HDR_LOCK(hdr)))
|
|
|
|
#define HDR_EQUAL(spa, dva, birth, hdr) \
|
|
((hdr)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \
|
|
((hdr)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \
|
|
((hdr)->b_birth == birth) && ((hdr)->b_spa == spa)
|
|
|
|
static void
|
|
buf_discard_identity(arc_buf_hdr_t *hdr)
|
|
{
|
|
hdr->b_dva.dva_word[0] = 0;
|
|
hdr->b_dva.dva_word[1] = 0;
|
|
hdr->b_birth = 0;
|
|
}
|
|
|
|
static arc_buf_hdr_t *
|
|
buf_hash_find(uint64_t spa, const blkptr_t *bp, kmutex_t **lockp)
|
|
{
|
|
const dva_t *dva = BP_IDENTITY(bp);
|
|
uint64_t birth = BP_PHYSICAL_BIRTH(bp);
|
|
uint64_t idx = BUF_HASH_INDEX(spa, dva, birth);
|
|
kmutex_t *hash_lock = BUF_HASH_LOCK(idx);
|
|
arc_buf_hdr_t *hdr;
|
|
|
|
mutex_enter(hash_lock);
|
|
for (hdr = buf_hash_table.ht_table[idx]; hdr != NULL;
|
|
hdr = hdr->b_hash_next) {
|
|
if (HDR_EQUAL(spa, dva, birth, hdr)) {
|
|
*lockp = hash_lock;
|
|
return (hdr);
|
|
}
|
|
}
|
|
mutex_exit(hash_lock);
|
|
*lockp = NULL;
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Insert an entry into the hash table. If there is already an element
|
|
* equal to elem in the hash table, then the already existing element
|
|
* will be returned and the new element will not be inserted.
|
|
* Otherwise returns NULL.
|
|
* If lockp == NULL, the caller is assumed to already hold the hash lock.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
buf_hash_insert(arc_buf_hdr_t *hdr, kmutex_t **lockp)
|
|
{
|
|
uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth);
|
|
kmutex_t *hash_lock = BUF_HASH_LOCK(idx);
|
|
arc_buf_hdr_t *fhdr;
|
|
uint32_t i;
|
|
|
|
ASSERT(!DVA_IS_EMPTY(&hdr->b_dva));
|
|
ASSERT(hdr->b_birth != 0);
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
|
|
if (lockp != NULL) {
|
|
*lockp = hash_lock;
|
|
mutex_enter(hash_lock);
|
|
} else {
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
}
|
|
|
|
for (fhdr = buf_hash_table.ht_table[idx], i = 0; fhdr != NULL;
|
|
fhdr = fhdr->b_hash_next, i++) {
|
|
if (HDR_EQUAL(hdr->b_spa, &hdr->b_dva, hdr->b_birth, fhdr))
|
|
return (fhdr);
|
|
}
|
|
|
|
hdr->b_hash_next = buf_hash_table.ht_table[idx];
|
|
buf_hash_table.ht_table[idx] = hdr;
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE);
|
|
|
|
/* collect some hash table performance data */
|
|
if (i > 0) {
|
|
ARCSTAT_BUMP(arcstat_hash_collisions);
|
|
if (i == 1)
|
|
ARCSTAT_BUMP(arcstat_hash_chains);
|
|
|
|
ARCSTAT_MAX(arcstat_hash_chain_max, i);
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_hash_elements);
|
|
ARCSTAT_MAXSTAT(arcstat_hash_elements);
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
buf_hash_remove(arc_buf_hdr_t *hdr)
|
|
{
|
|
arc_buf_hdr_t *fhdr, **hdrp;
|
|
uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth);
|
|
|
|
ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx)));
|
|
ASSERT(HDR_IN_HASH_TABLE(hdr));
|
|
|
|
hdrp = &buf_hash_table.ht_table[idx];
|
|
while ((fhdr = *hdrp) != hdr) {
|
|
ASSERT3P(fhdr, !=, NULL);
|
|
hdrp = &fhdr->b_hash_next;
|
|
}
|
|
*hdrp = hdr->b_hash_next;
|
|
hdr->b_hash_next = NULL;
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_IN_HASH_TABLE);
|
|
|
|
/* collect some hash table performance data */
|
|
ARCSTAT_BUMPDOWN(arcstat_hash_elements);
|
|
|
|
if (buf_hash_table.ht_table[idx] &&
|
|
buf_hash_table.ht_table[idx]->b_hash_next == NULL)
|
|
ARCSTAT_BUMPDOWN(arcstat_hash_chains);
|
|
}
|
|
|
|
/*
|
|
* Global data structures and functions for the buf kmem cache.
|
|
*/
|
|
|
|
static kmem_cache_t *hdr_full_cache;
|
|
static kmem_cache_t *hdr_full_crypt_cache;
|
|
static kmem_cache_t *hdr_l2only_cache;
|
|
static kmem_cache_t *buf_cache;
|
|
|
|
static void
|
|
buf_fini(void)
|
|
{
|
|
int i;
|
|
|
|
#if defined(_KERNEL)
|
|
/*
|
|
* Large allocations which do not require contiguous pages
|
|
* should be using vmem_free() in the linux kernel\
|
|
*/
|
|
vmem_free(buf_hash_table.ht_table,
|
|
(buf_hash_table.ht_mask + 1) * sizeof (void *));
|
|
#else
|
|
kmem_free(buf_hash_table.ht_table,
|
|
(buf_hash_table.ht_mask + 1) * sizeof (void *));
|
|
#endif
|
|
for (i = 0; i < BUF_LOCKS; i++)
|
|
mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock);
|
|
kmem_cache_destroy(hdr_full_cache);
|
|
kmem_cache_destroy(hdr_full_crypt_cache);
|
|
kmem_cache_destroy(hdr_l2only_cache);
|
|
kmem_cache_destroy(buf_cache);
|
|
}
|
|
|
|
/*
|
|
* Constructor callback - called when the cache is empty
|
|
* and a new buf is requested.
|
|
*/
|
|
/* ARGSUSED */
|
|
static int
|
|
hdr_full_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
bzero(hdr, HDR_FULL_SIZE);
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS;
|
|
cv_init(&hdr->b_l1hdr.b_cv, NULL, CV_DEFAULT, NULL);
|
|
zfs_refcount_create(&hdr->b_l1hdr.b_refcnt);
|
|
mutex_init(&hdr->b_l1hdr.b_freeze_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
list_link_init(&hdr->b_l1hdr.b_arc_node);
|
|
list_link_init(&hdr->b_l2hdr.b_l2node);
|
|
multilist_link_init(&hdr->b_l1hdr.b_arc_node);
|
|
arc_space_consume(HDR_FULL_SIZE, ARC_SPACE_HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
hdr_full_crypt_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
hdr_full_cons(vbuf, unused, kmflag);
|
|
bzero(&hdr->b_crypt_hdr, sizeof (hdr->b_crypt_hdr));
|
|
arc_space_consume(sizeof (hdr->b_crypt_hdr), ARC_SPACE_HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
hdr_l2only_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
bzero(hdr, HDR_L2ONLY_SIZE);
|
|
arc_space_consume(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
buf_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_t *buf = vbuf;
|
|
|
|
bzero(buf, sizeof (arc_buf_t));
|
|
mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Destructor callback - called when a cached buf is
|
|
* no longer required.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
hdr_full_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
ASSERT(HDR_EMPTY(hdr));
|
|
cv_destroy(&hdr->b_l1hdr.b_cv);
|
|
zfs_refcount_destroy(&hdr->b_l1hdr.b_refcnt);
|
|
mutex_destroy(&hdr->b_l1hdr.b_freeze_lock);
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
arc_space_return(HDR_FULL_SIZE, ARC_SPACE_HDRS);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
hdr_full_crypt_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
hdr_full_dest(vbuf, unused);
|
|
arc_space_return(sizeof (hdr->b_crypt_hdr), ARC_SPACE_HDRS);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
hdr_l2only_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_hdr_t *hdr __maybe_unused = vbuf;
|
|
|
|
ASSERT(HDR_EMPTY(hdr));
|
|
arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
buf_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_t *buf = vbuf;
|
|
|
|
mutex_destroy(&buf->b_evict_lock);
|
|
arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS);
|
|
}
|
|
|
|
static void
|
|
buf_init(void)
|
|
{
|
|
uint64_t *ct = NULL;
|
|
uint64_t hsize = 1ULL << 12;
|
|
int i, j;
|
|
|
|
/*
|
|
* The hash table is big enough to fill all of physical memory
|
|
* with an average block size of zfs_arc_average_blocksize (default 8K).
|
|
* By default, the table will take up
|
|
* totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers).
|
|
*/
|
|
while (hsize * zfs_arc_average_blocksize < arc_all_memory())
|
|
hsize <<= 1;
|
|
retry:
|
|
buf_hash_table.ht_mask = hsize - 1;
|
|
#if defined(_KERNEL)
|
|
/*
|
|
* Large allocations which do not require contiguous pages
|
|
* should be using vmem_alloc() in the linux kernel
|
|
*/
|
|
buf_hash_table.ht_table =
|
|
vmem_zalloc(hsize * sizeof (void*), KM_SLEEP);
|
|
#else
|
|
buf_hash_table.ht_table =
|
|
kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP);
|
|
#endif
|
|
if (buf_hash_table.ht_table == NULL) {
|
|
ASSERT(hsize > (1ULL << 8));
|
|
hsize >>= 1;
|
|
goto retry;
|
|
}
|
|
|
|
hdr_full_cache = kmem_cache_create("arc_buf_hdr_t_full", HDR_FULL_SIZE,
|
|
0, hdr_full_cons, hdr_full_dest, NULL, NULL, NULL, 0);
|
|
hdr_full_crypt_cache = kmem_cache_create("arc_buf_hdr_t_full_crypt",
|
|
HDR_FULL_CRYPT_SIZE, 0, hdr_full_crypt_cons, hdr_full_crypt_dest,
|
|
NULL, NULL, NULL, 0);
|
|
hdr_l2only_cache = kmem_cache_create("arc_buf_hdr_t_l2only",
|
|
HDR_L2ONLY_SIZE, 0, hdr_l2only_cons, hdr_l2only_dest, NULL,
|
|
NULL, NULL, 0);
|
|
buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t),
|
|
0, buf_cons, buf_dest, NULL, NULL, NULL, 0);
|
|
|
|
for (i = 0; i < 256; i++)
|
|
for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--)
|
|
*ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY);
|
|
|
|
for (i = 0; i < BUF_LOCKS; i++) {
|
|
mutex_init(&buf_hash_table.ht_locks[i].ht_lock,
|
|
NULL, MUTEX_DEFAULT, NULL);
|
|
}
|
|
}
|
|
|
|
#define ARC_MINTIME (hz>>4) /* 62 ms */
|
|
|
|
/*
|
|
* This is the size that the buf occupies in memory. If the buf is compressed,
|
|
* it will correspond to the compressed size. You should use this method of
|
|
* getting the buf size unless you explicitly need the logical size.
|
|
*/
|
|
uint64_t
|
|
arc_buf_size(arc_buf_t *buf)
|
|
{
|
|
return (ARC_BUF_COMPRESSED(buf) ?
|
|
HDR_GET_PSIZE(buf->b_hdr) : HDR_GET_LSIZE(buf->b_hdr));
|
|
}
|
|
|
|
uint64_t
|
|
arc_buf_lsize(arc_buf_t *buf)
|
|
{
|
|
return (HDR_GET_LSIZE(buf->b_hdr));
|
|
}
|
|
|
|
/*
|
|
* This function will return B_TRUE if the buffer is encrypted in memory.
|
|
* This buffer can be decrypted by calling arc_untransform().
|
|
*/
|
|
boolean_t
|
|
arc_is_encrypted(arc_buf_t *buf)
|
|
{
|
|
return (ARC_BUF_ENCRYPTED(buf) != 0);
|
|
}
|
|
|
|
/*
|
|
* Returns B_TRUE if the buffer represents data that has not had its MAC
|
|
* verified yet.
|
|
*/
|
|
boolean_t
|
|
arc_is_unauthenticated(arc_buf_t *buf)
|
|
{
|
|
return (HDR_NOAUTH(buf->b_hdr) != 0);
|
|
}
|
|
|
|
void
|
|
arc_get_raw_params(arc_buf_t *buf, boolean_t *byteorder, uint8_t *salt,
|
|
uint8_t *iv, uint8_t *mac)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(HDR_PROTECTED(hdr));
|
|
|
|
bcopy(hdr->b_crypt_hdr.b_salt, salt, ZIO_DATA_SALT_LEN);
|
|
bcopy(hdr->b_crypt_hdr.b_iv, iv, ZIO_DATA_IV_LEN);
|
|
bcopy(hdr->b_crypt_hdr.b_mac, mac, ZIO_DATA_MAC_LEN);
|
|
*byteorder = (hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ?
|
|
ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER;
|
|
}
|
|
|
|
/*
|
|
* Indicates how this buffer is compressed in memory. If it is not compressed
|
|
* the value will be ZIO_COMPRESS_OFF. It can be made normally readable with
|
|
* arc_untransform() as long as it is also unencrypted.
|
|
*/
|
|
enum zio_compress
|
|
arc_get_compression(arc_buf_t *buf)
|
|
{
|
|
return (ARC_BUF_COMPRESSED(buf) ?
|
|
HDR_GET_COMPRESS(buf->b_hdr) : ZIO_COMPRESS_OFF);
|
|
}
|
|
|
|
/*
|
|
* Return the compression algorithm used to store this data in the ARC. If ARC
|
|
* compression is enabled or this is an encrypted block, this will be the same
|
|
* as what's used to store it on-disk. Otherwise, this will be ZIO_COMPRESS_OFF.
|
|
*/
|
|
static inline enum zio_compress
|
|
arc_hdr_get_compress(arc_buf_hdr_t *hdr)
|
|
{
|
|
return (HDR_COMPRESSION_ENABLED(hdr) ?
|
|
HDR_GET_COMPRESS(hdr) : ZIO_COMPRESS_OFF);
|
|
}
|
|
|
|
uint8_t
|
|
arc_get_complevel(arc_buf_t *buf)
|
|
{
|
|
return (buf->b_hdr->b_complevel);
|
|
}
|
|
|
|
static inline boolean_t
|
|
arc_buf_is_shared(arc_buf_t *buf)
|
|
{
|
|
boolean_t shared = (buf->b_data != NULL &&
|
|
buf->b_hdr->b_l1hdr.b_pabd != NULL &&
|
|
abd_is_linear(buf->b_hdr->b_l1hdr.b_pabd) &&
|
|
buf->b_data == abd_to_buf(buf->b_hdr->b_l1hdr.b_pabd));
|
|
IMPLY(shared, HDR_SHARED_DATA(buf->b_hdr));
|
|
IMPLY(shared, ARC_BUF_SHARED(buf));
|
|
IMPLY(shared, ARC_BUF_COMPRESSED(buf) || ARC_BUF_LAST(buf));
|
|
|
|
/*
|
|
* It would be nice to assert arc_can_share() too, but the "hdr isn't
|
|
* already being shared" requirement prevents us from doing that.
|
|
*/
|
|
|
|
return (shared);
|
|
}
|
|
|
|
/*
|
|
* Free the checksum associated with this header. If there is no checksum, this
|
|
* is a no-op.
|
|
*/
|
|
static inline void
|
|
arc_cksum_free(arc_buf_hdr_t *hdr)
|
|
{
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
mutex_enter(&hdr->b_l1hdr.b_freeze_lock);
|
|
if (hdr->b_l1hdr.b_freeze_cksum != NULL) {
|
|
kmem_free(hdr->b_l1hdr.b_freeze_cksum, sizeof (zio_cksum_t));
|
|
hdr->b_l1hdr.b_freeze_cksum = NULL;
|
|
}
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
}
|
|
|
|
/*
|
|
* Return true iff at least one of the bufs on hdr is not compressed.
|
|
* Encrypted buffers count as compressed.
|
|
*/
|
|
static boolean_t
|
|
arc_hdr_has_uncompressed_buf(arc_buf_hdr_t *hdr)
|
|
{
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
for (arc_buf_t *b = hdr->b_l1hdr.b_buf; b != NULL; b = b->b_next) {
|
|
if (!ARC_BUF_COMPRESSED(b)) {
|
|
return (B_TRUE);
|
|
}
|
|
}
|
|
return (B_FALSE);
|
|
}
|
|
|
|
|
|
/*
|
|
* If we've turned on the ZFS_DEBUG_MODIFY flag, verify that the buf's data
|
|
* matches the checksum that is stored in the hdr. If there is no checksum,
|
|
* or if the buf is compressed, this is a no-op.
|
|
*/
|
|
static void
|
|
arc_cksum_verify(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
zio_cksum_t zc;
|
|
|
|
if (!(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
if (ARC_BUF_COMPRESSED(buf))
|
|
return;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
mutex_enter(&hdr->b_l1hdr.b_freeze_lock);
|
|
|
|
if (hdr->b_l1hdr.b_freeze_cksum == NULL || HDR_IO_ERROR(hdr)) {
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
return;
|
|
}
|
|
|
|
fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL, &zc);
|
|
if (!ZIO_CHECKSUM_EQUAL(*hdr->b_l1hdr.b_freeze_cksum, zc))
|
|
panic("buffer modified while frozen!");
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
}
|
|
|
|
/*
|
|
* This function makes the assumption that data stored in the L2ARC
|
|
* will be transformed exactly as it is in the main pool. Because of
|
|
* this we can verify the checksum against the reading process's bp.
|
|
*/
|
|
static boolean_t
|
|
arc_cksum_is_equal(arc_buf_hdr_t *hdr, zio_t *zio)
|
|
{
|
|
ASSERT(!BP_IS_EMBEDDED(zio->io_bp));
|
|
VERIFY3U(BP_GET_PSIZE(zio->io_bp), ==, HDR_GET_PSIZE(hdr));
|
|
|
|
/*
|
|
* Block pointers always store the checksum for the logical data.
|
|
* If the block pointer has the gang bit set, then the checksum
|
|
* it represents is for the reconstituted data and not for an
|
|
* individual gang member. The zio pipeline, however, must be able to
|
|
* determine the checksum of each of the gang constituents so it
|
|
* treats the checksum comparison differently than what we need
|
|
* for l2arc blocks. This prevents us from using the
|
|
* zio_checksum_error() interface directly. Instead we must call the
|
|
* zio_checksum_error_impl() so that we can ensure the checksum is
|
|
* generated using the correct checksum algorithm and accounts for the
|
|
* logical I/O size and not just a gang fragment.
|
|
*/
|
|
return (zio_checksum_error_impl(zio->io_spa, zio->io_bp,
|
|
BP_GET_CHECKSUM(zio->io_bp), zio->io_abd, zio->io_size,
|
|
zio->io_offset, NULL) == 0);
|
|
}
|
|
|
|
/*
|
|
* Given a buf full of data, if ZFS_DEBUG_MODIFY is enabled this computes a
|
|
* checksum and attaches it to the buf's hdr so that we can ensure that the buf
|
|
* isn't modified later on. If buf is compressed or there is already a checksum
|
|
* on the hdr, this is a no-op (we only checksum uncompressed bufs).
|
|
*/
|
|
static void
|
|
arc_cksum_compute(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
if (!(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
if (hdr->b_l1hdr.b_freeze_cksum != NULL || ARC_BUF_COMPRESSED(buf)) {
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
return;
|
|
}
|
|
|
|
ASSERT(!ARC_BUF_ENCRYPTED(buf));
|
|
ASSERT(!ARC_BUF_COMPRESSED(buf));
|
|
hdr->b_l1hdr.b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t),
|
|
KM_SLEEP);
|
|
fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL,
|
|
hdr->b_l1hdr.b_freeze_cksum);
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
arc_buf_watch(buf);
|
|
}
|
|
|
|
#ifndef _KERNEL
|
|
void
|
|
arc_buf_sigsegv(int sig, siginfo_t *si, void *unused)
|
|
{
|
|
panic("Got SIGSEGV at address: 0x%lx\n", (long)si->si_addr);
|
|
}
|
|
#endif
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_buf_unwatch(arc_buf_t *buf)
|
|
{
|
|
#ifndef _KERNEL
|
|
if (arc_watch) {
|
|
ASSERT0(mprotect(buf->b_data, arc_buf_size(buf),
|
|
PROT_READ | PROT_WRITE));
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_buf_watch(arc_buf_t *buf)
|
|
{
|
|
#ifndef _KERNEL
|
|
if (arc_watch)
|
|
ASSERT0(mprotect(buf->b_data, arc_buf_size(buf),
|
|
PROT_READ));
|
|
#endif
|
|
}
|
|
|
|
static arc_buf_contents_t
|
|
arc_buf_type(arc_buf_hdr_t *hdr)
|
|
{
|
|
arc_buf_contents_t type;
|
|
if (HDR_ISTYPE_METADATA(hdr)) {
|
|
type = ARC_BUFC_METADATA;
|
|
} else {
|
|
type = ARC_BUFC_DATA;
|
|
}
|
|
VERIFY3U(hdr->b_type, ==, type);
|
|
return (type);
|
|
}
|
|
|
|
boolean_t
|
|
arc_is_metadata(arc_buf_t *buf)
|
|
{
|
|
return (HDR_ISTYPE_METADATA(buf->b_hdr) != 0);
|
|
}
|
|
|
|
static uint32_t
|
|
arc_bufc_to_flags(arc_buf_contents_t type)
|
|
{
|
|
switch (type) {
|
|
case ARC_BUFC_DATA:
|
|
/* metadata field is 0 if buffer contains normal data */
|
|
return (0);
|
|
case ARC_BUFC_METADATA:
|
|
return (ARC_FLAG_BUFC_METADATA);
|
|
default:
|
|
break;
|
|
}
|
|
panic("undefined ARC buffer type!");
|
|
return ((uint32_t)-1);
|
|
}
|
|
|
|
void
|
|
arc_buf_thaw(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
|
|
arc_cksum_verify(buf);
|
|
|
|
/*
|
|
* Compressed buffers do not manipulate the b_freeze_cksum.
|
|
*/
|
|
if (ARC_BUF_COMPRESSED(buf))
|
|
return;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
arc_cksum_free(hdr);
|
|
arc_buf_unwatch(buf);
|
|
}
|
|
|
|
void
|
|
arc_buf_freeze(arc_buf_t *buf)
|
|
{
|
|
if (!(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
if (ARC_BUF_COMPRESSED(buf))
|
|
return;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(buf->b_hdr));
|
|
arc_cksum_compute(buf);
|
|
}
|
|
|
|
/*
|
|
* The arc_buf_hdr_t's b_flags should never be modified directly. Instead,
|
|
* the following functions should be used to ensure that the flags are
|
|
* updated in a thread-safe way. When manipulating the flags either
|
|
* the hash_lock must be held or the hdr must be undiscoverable. This
|
|
* ensures that we're not racing with any other threads when updating
|
|
* the flags.
|
|
*/
|
|
static inline void
|
|
arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags)
|
|
{
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
hdr->b_flags |= flags;
|
|
}
|
|
|
|
static inline void
|
|
arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags)
|
|
{
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
hdr->b_flags &= ~flags;
|
|
}
|
|
|
|
/*
|
|
* Setting the compression bits in the arc_buf_hdr_t's b_flags is
|
|
* done in a special way since we have to clear and set bits
|
|
* at the same time. Consumers that wish to set the compression bits
|
|
* must use this function to ensure that the flags are updated in
|
|
* thread-safe manner.
|
|
*/
|
|
static void
|
|
arc_hdr_set_compress(arc_buf_hdr_t *hdr, enum zio_compress cmp)
|
|
{
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
/*
|
|
* Holes and embedded blocks will always have a psize = 0 so
|
|
* we ignore the compression of the blkptr and set the
|
|
* want to uncompress them. Mark them as uncompressed.
|
|
*/
|
|
if (!zfs_compressed_arc_enabled || HDR_GET_PSIZE(hdr) == 0) {
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_COMPRESSED_ARC);
|
|
ASSERT(!HDR_COMPRESSION_ENABLED(hdr));
|
|
} else {
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_COMPRESSED_ARC);
|
|
ASSERT(HDR_COMPRESSION_ENABLED(hdr));
|
|
}
|
|
|
|
HDR_SET_COMPRESS(hdr, cmp);
|
|
ASSERT3U(HDR_GET_COMPRESS(hdr), ==, cmp);
|
|
}
|
|
|
|
/*
|
|
* Looks for another buf on the same hdr which has the data decompressed, copies
|
|
* from it, and returns true. If no such buf exists, returns false.
|
|
*/
|
|
static boolean_t
|
|
arc_buf_try_copy_decompressed_data(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
boolean_t copied = B_FALSE;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT3P(buf->b_data, !=, NULL);
|
|
ASSERT(!ARC_BUF_COMPRESSED(buf));
|
|
|
|
for (arc_buf_t *from = hdr->b_l1hdr.b_buf; from != NULL;
|
|
from = from->b_next) {
|
|
/* can't use our own data buffer */
|
|
if (from == buf) {
|
|
continue;
|
|
}
|
|
|
|
if (!ARC_BUF_COMPRESSED(from)) {
|
|
bcopy(from->b_data, buf->b_data, arc_buf_size(buf));
|
|
copied = B_TRUE;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* There were no decompressed bufs, so there should not be a
|
|
* checksum on the hdr either.
|
|
*/
|
|
if (zfs_flags & ZFS_DEBUG_MODIFY)
|
|
EQUIV(!copied, hdr->b_l1hdr.b_freeze_cksum == NULL);
|
|
|
|
return (copied);
|
|
}
|
|
|
|
/*
|
|
* Allocates an ARC buf header that's in an evicted & L2-cached state.
|
|
* This is used during l2arc reconstruction to make empty ARC buffers
|
|
* which circumvent the regular disk->arc->l2arc path and instead come
|
|
* into being in the reverse order, i.e. l2arc->arc.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
arc_buf_alloc_l2only(size_t size, arc_buf_contents_t type, l2arc_dev_t *dev,
|
|
dva_t dva, uint64_t daddr, int32_t psize, uint64_t birth,
|
|
enum zio_compress compress, uint8_t complevel, boolean_t protected,
|
|
boolean_t prefetch)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
|
|
ASSERT(size != 0);
|
|
hdr = kmem_cache_alloc(hdr_l2only_cache, KM_SLEEP);
|
|
hdr->b_birth = birth;
|
|
hdr->b_type = type;
|
|
hdr->b_flags = 0;
|
|
arc_hdr_set_flags(hdr, arc_bufc_to_flags(type) | ARC_FLAG_HAS_L2HDR);
|
|
HDR_SET_LSIZE(hdr, size);
|
|
HDR_SET_PSIZE(hdr, psize);
|
|
arc_hdr_set_compress(hdr, compress);
|
|
hdr->b_complevel = complevel;
|
|
if (protected)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PROTECTED);
|
|
if (prefetch)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH);
|
|
hdr->b_spa = spa_load_guid(dev->l2ad_vdev->vdev_spa);
|
|
|
|
hdr->b_dva = dva;
|
|
|
|
hdr->b_l2hdr.b_dev = dev;
|
|
hdr->b_l2hdr.b_daddr = daddr;
|
|
|
|
return (hdr);
|
|
}
|
|
|
|
/*
|
|
* Return the size of the block, b_pabd, that is stored in the arc_buf_hdr_t.
|
|
*/
|
|
static uint64_t
|
|
arc_hdr_size(arc_buf_hdr_t *hdr)
|
|
{
|
|
uint64_t size;
|
|
|
|
if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF &&
|
|
HDR_GET_PSIZE(hdr) > 0) {
|
|
size = HDR_GET_PSIZE(hdr);
|
|
} else {
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), !=, 0);
|
|
size = HDR_GET_LSIZE(hdr);
|
|
}
|
|
return (size);
|
|
}
|
|
|
|
static int
|
|
arc_hdr_authenticate(arc_buf_hdr_t *hdr, spa_t *spa, uint64_t dsobj)
|
|
{
|
|
int ret;
|
|
uint64_t csize;
|
|
uint64_t lsize = HDR_GET_LSIZE(hdr);
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
void *tmpbuf = NULL;
|
|
abd_t *abd = hdr->b_l1hdr.b_pabd;
|
|
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
ASSERT(HDR_AUTHENTICATED(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
|
|
/*
|
|
* The MAC is calculated on the compressed data that is stored on disk.
|
|
* However, if compressed arc is disabled we will only have the
|
|
* decompressed data available to us now. Compress it into a temporary
|
|
* abd so we can verify the MAC. The performance overhead of this will
|
|
* be relatively low, since most objects in an encrypted objset will
|
|
* be encrypted (instead of authenticated) anyway.
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
|
|
!HDR_COMPRESSION_ENABLED(hdr)) {
|
|
tmpbuf = zio_buf_alloc(lsize);
|
|
abd = abd_get_from_buf(tmpbuf, lsize);
|
|
abd_take_ownership_of_buf(abd, B_TRUE);
|
|
csize = zio_compress_data(HDR_GET_COMPRESS(hdr),
|
|
hdr->b_l1hdr.b_pabd, tmpbuf, lsize, hdr->b_complevel);
|
|
ASSERT3U(csize, <=, psize);
|
|
abd_zero_off(abd, csize, psize - csize);
|
|
}
|
|
|
|
/*
|
|
* Authentication is best effort. We authenticate whenever the key is
|
|
* available. If we succeed we clear ARC_FLAG_NOAUTH.
|
|
*/
|
|
if (hdr->b_crypt_hdr.b_ot == DMU_OT_OBJSET) {
|
|
ASSERT3U(HDR_GET_COMPRESS(hdr), ==, ZIO_COMPRESS_OFF);
|
|
ASSERT3U(lsize, ==, psize);
|
|
ret = spa_do_crypt_objset_mac_abd(B_FALSE, spa, dsobj, abd,
|
|
psize, hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS);
|
|
} else {
|
|
ret = spa_do_crypt_mac_abd(B_FALSE, spa, dsobj, abd, psize,
|
|
hdr->b_crypt_hdr.b_mac);
|
|
}
|
|
|
|
if (ret == 0)
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_NOAUTH);
|
|
else if (ret != ENOENT)
|
|
goto error;
|
|
|
|
if (tmpbuf != NULL)
|
|
abd_free(abd);
|
|
|
|
return (0);
|
|
|
|
error:
|
|
if (tmpbuf != NULL)
|
|
abd_free(abd);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* This function will take a header that only has raw encrypted data in
|
|
* b_crypt_hdr.b_rabd and decrypt it into a new buffer which is stored in
|
|
* b_l1hdr.b_pabd. If designated in the header flags, this function will
|
|
* also decompress the data.
|
|
*/
|
|
static int
|
|
arc_hdr_decrypt(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb)
|
|
{
|
|
int ret;
|
|
abd_t *cabd = NULL;
|
|
void *tmp = NULL;
|
|
boolean_t no_crypt = B_FALSE;
|
|
boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS);
|
|
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
ASSERT(HDR_ENCRYPTED(hdr));
|
|
|
|
arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT);
|
|
|
|
ret = spa_do_crypt_abd(B_FALSE, spa, zb, hdr->b_crypt_hdr.b_ot,
|
|
B_FALSE, bswap, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv,
|
|
hdr->b_crypt_hdr.b_mac, HDR_GET_PSIZE(hdr), hdr->b_l1hdr.b_pabd,
|
|
hdr->b_crypt_hdr.b_rabd, &no_crypt);
|
|
if (ret != 0)
|
|
goto error;
|
|
|
|
if (no_crypt) {
|
|
abd_copy(hdr->b_l1hdr.b_pabd, hdr->b_crypt_hdr.b_rabd,
|
|
HDR_GET_PSIZE(hdr));
|
|
}
|
|
|
|
/*
|
|
* If this header has disabled arc compression but the b_pabd is
|
|
* compressed after decrypting it, we need to decompress the newly
|
|
* decrypted data.
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
|
|
!HDR_COMPRESSION_ENABLED(hdr)) {
|
|
/*
|
|
* We want to make sure that we are correctly honoring the
|
|
* zfs_abd_scatter_enabled setting, so we allocate an abd here
|
|
* and then loan a buffer from it, rather than allocating a
|
|
* linear buffer and wrapping it in an abd later.
|
|
*/
|
|
cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, B_TRUE);
|
|
tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr));
|
|
|
|
ret = zio_decompress_data(HDR_GET_COMPRESS(hdr),
|
|
hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr),
|
|
HDR_GET_LSIZE(hdr), &hdr->b_complevel);
|
|
if (ret != 0) {
|
|
abd_return_buf(cabd, tmp, arc_hdr_size(hdr));
|
|
goto error;
|
|
}
|
|
|
|
abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr));
|
|
arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd,
|
|
arc_hdr_size(hdr), hdr);
|
|
hdr->b_l1hdr.b_pabd = cabd;
|
|
}
|
|
|
|
return (0);
|
|
|
|
error:
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
if (cabd != NULL)
|
|
arc_free_data_buf(hdr, cabd, arc_hdr_size(hdr), hdr);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* This function is called during arc_buf_fill() to prepare the header's
|
|
* abd plaintext pointer for use. This involves authenticated protected
|
|
* data and decrypting encrypted data into the plaintext abd.
|
|
*/
|
|
static int
|
|
arc_fill_hdr_crypt(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, spa_t *spa,
|
|
const zbookmark_phys_t *zb, boolean_t noauth)
|
|
{
|
|
int ret;
|
|
|
|
ASSERT(HDR_PROTECTED(hdr));
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_enter(hash_lock);
|
|
|
|
if (HDR_NOAUTH(hdr) && !noauth) {
|
|
/*
|
|
* The caller requested authenticated data but our data has
|
|
* not been authenticated yet. Verify the MAC now if we can.
|
|
*/
|
|
ret = arc_hdr_authenticate(hdr, spa, zb->zb_objset);
|
|
if (ret != 0)
|
|
goto error;
|
|
} else if (HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd == NULL) {
|
|
/*
|
|
* If we only have the encrypted version of the data, but the
|
|
* unencrypted version was requested we take this opportunity
|
|
* to store the decrypted version in the header for future use.
|
|
*/
|
|
ret = arc_hdr_decrypt(hdr, spa, zb);
|
|
if (ret != 0)
|
|
goto error;
|
|
}
|
|
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
return (0);
|
|
|
|
error:
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* This function is used by the dbuf code to decrypt bonus buffers in place.
|
|
* The dbuf code itself doesn't have any locking for decrypting a shared dnode
|
|
* block, so we use the hash lock here to protect against concurrent calls to
|
|
* arc_buf_fill().
|
|
*/
|
|
static void
|
|
arc_buf_untransform_in_place(arc_buf_t *buf, kmutex_t *hash_lock)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(HDR_ENCRYPTED(hdr));
|
|
ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE);
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
|
|
zio_crypt_copy_dnode_bonus(hdr->b_l1hdr.b_pabd, buf->b_data,
|
|
arc_buf_size(buf));
|
|
buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED;
|
|
buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
|
|
hdr->b_crypt_hdr.b_ebufcnt -= 1;
|
|
}
|
|
|
|
/*
|
|
* Given a buf that has a data buffer attached to it, this function will
|
|
* efficiently fill the buf with data of the specified compression setting from
|
|
* the hdr and update the hdr's b_freeze_cksum if necessary. If the buf and hdr
|
|
* are already sharing a data buf, no copy is performed.
|
|
*
|
|
* If the buf is marked as compressed but uncompressed data was requested, this
|
|
* will allocate a new data buffer for the buf, remove that flag, and fill the
|
|
* buf with uncompressed data. You can't request a compressed buf on a hdr with
|
|
* uncompressed data, and (since we haven't added support for it yet) if you
|
|
* want compressed data your buf must already be marked as compressed and have
|
|
* the correct-sized data buffer.
|
|
*/
|
|
static int
|
|
arc_buf_fill(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb,
|
|
arc_fill_flags_t flags)
|
|
{
|
|
int error = 0;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
boolean_t hdr_compressed =
|
|
(arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF);
|
|
boolean_t compressed = (flags & ARC_FILL_COMPRESSED) != 0;
|
|
boolean_t encrypted = (flags & ARC_FILL_ENCRYPTED) != 0;
|
|
dmu_object_byteswap_t bswap = hdr->b_l1hdr.b_byteswap;
|
|
kmutex_t *hash_lock = (flags & ARC_FILL_LOCKED) ? NULL : HDR_LOCK(hdr);
|
|
|
|
ASSERT3P(buf->b_data, !=, NULL);
|
|
IMPLY(compressed, hdr_compressed || ARC_BUF_ENCRYPTED(buf));
|
|
IMPLY(compressed, ARC_BUF_COMPRESSED(buf));
|
|
IMPLY(encrypted, HDR_ENCRYPTED(hdr));
|
|
IMPLY(encrypted, ARC_BUF_ENCRYPTED(buf));
|
|
IMPLY(encrypted, ARC_BUF_COMPRESSED(buf));
|
|
IMPLY(encrypted, !ARC_BUF_SHARED(buf));
|
|
|
|
/*
|
|
* If the caller wanted encrypted data we just need to copy it from
|
|
* b_rabd and potentially byteswap it. We won't be able to do any
|
|
* further transforms on it.
|
|
*/
|
|
if (encrypted) {
|
|
ASSERT(HDR_HAS_RABD(hdr));
|
|
abd_copy_to_buf(buf->b_data, hdr->b_crypt_hdr.b_rabd,
|
|
HDR_GET_PSIZE(hdr));
|
|
goto byteswap;
|
|
}
|
|
|
|
/*
|
|
* Adjust encrypted and authenticated headers to accommodate
|
|
* the request if needed. Dnode blocks (ARC_FILL_IN_PLACE) are
|
|
* allowed to fail decryption due to keys not being loaded
|
|
* without being marked as an IO error.
|
|
*/
|
|
if (HDR_PROTECTED(hdr)) {
|
|
error = arc_fill_hdr_crypt(hdr, hash_lock, spa,
|
|
zb, !!(flags & ARC_FILL_NOAUTH));
|
|
if (error == EACCES && (flags & ARC_FILL_IN_PLACE) != 0) {
|
|
return (error);
|
|
} else if (error != 0) {
|
|
if (hash_lock != NULL)
|
|
mutex_enter(hash_lock);
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR);
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* There is a special case here for dnode blocks which are
|
|
* decrypting their bonus buffers. These blocks may request to
|
|
* be decrypted in-place. This is necessary because there may
|
|
* be many dnodes pointing into this buffer and there is
|
|
* currently no method to synchronize replacing the backing
|
|
* b_data buffer and updating all of the pointers. Here we use
|
|
* the hash lock to ensure there are no races. If the need
|
|
* arises for other types to be decrypted in-place, they must
|
|
* add handling here as well.
|
|
*/
|
|
if ((flags & ARC_FILL_IN_PLACE) != 0) {
|
|
ASSERT(!hdr_compressed);
|
|
ASSERT(!compressed);
|
|
ASSERT(!encrypted);
|
|
|
|
if (HDR_ENCRYPTED(hdr) && ARC_BUF_ENCRYPTED(buf)) {
|
|
ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE);
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_enter(hash_lock);
|
|
arc_buf_untransform_in_place(buf, hash_lock);
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
/* Compute the hdr's checksum if necessary */
|
|
arc_cksum_compute(buf);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
if (hdr_compressed == compressed) {
|
|
if (!arc_buf_is_shared(buf)) {
|
|
abd_copy_to_buf(buf->b_data, hdr->b_l1hdr.b_pabd,
|
|
arc_buf_size(buf));
|
|
}
|
|
} else {
|
|
ASSERT(hdr_compressed);
|
|
ASSERT(!compressed);
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), !=, HDR_GET_PSIZE(hdr));
|
|
|
|
/*
|
|
* If the buf is sharing its data with the hdr, unlink it and
|
|
* allocate a new data buffer for the buf.
|
|
*/
|
|
if (arc_buf_is_shared(buf)) {
|
|
ASSERT(ARC_BUF_COMPRESSED(buf));
|
|
|
|
/* We need to give the buf its own b_data */
|
|
buf->b_flags &= ~ARC_BUF_FLAG_SHARED;
|
|
buf->b_data =
|
|
arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf);
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA);
|
|
|
|
/* Previously overhead was 0; just add new overhead */
|
|
ARCSTAT_INCR(arcstat_overhead_size, HDR_GET_LSIZE(hdr));
|
|
} else if (ARC_BUF_COMPRESSED(buf)) {
|
|
/* We need to reallocate the buf's b_data */
|
|
arc_free_data_buf(hdr, buf->b_data, HDR_GET_PSIZE(hdr),
|
|
buf);
|
|
buf->b_data =
|
|
arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf);
|
|
|
|
/* We increased the size of b_data; update overhead */
|
|
ARCSTAT_INCR(arcstat_overhead_size,
|
|
HDR_GET_LSIZE(hdr) - HDR_GET_PSIZE(hdr));
|
|
}
|
|
|
|
/*
|
|
* Regardless of the buf's previous compression settings, it
|
|
* should not be compressed at the end of this function.
|
|
*/
|
|
buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
|
|
|
|
/*
|
|
* Try copying the data from another buf which already has a
|
|
* decompressed version. If that's not possible, it's time to
|
|
* bite the bullet and decompress the data from the hdr.
|
|
*/
|
|
if (arc_buf_try_copy_decompressed_data(buf)) {
|
|
/* Skip byteswapping and checksumming (already done) */
|
|
return (0);
|
|
} else {
|
|
error = zio_decompress_data(HDR_GET_COMPRESS(hdr),
|
|
hdr->b_l1hdr.b_pabd, buf->b_data,
|
|
HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr),
|
|
&hdr->b_complevel);
|
|
|
|
/*
|
|
* Absent hardware errors or software bugs, this should
|
|
* be impossible, but log it anyway so we can debug it.
|
|
*/
|
|
if (error != 0) {
|
|
zfs_dbgmsg(
|
|
"hdr %px, compress %d, psize %d, lsize %d",
|
|
hdr, arc_hdr_get_compress(hdr),
|
|
HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr));
|
|
if (hash_lock != NULL)
|
|
mutex_enter(hash_lock);
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR);
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
return (SET_ERROR(EIO));
|
|
}
|
|
}
|
|
}
|
|
|
|
byteswap:
|
|
/* Byteswap the buf's data if necessary */
|
|
if (bswap != DMU_BSWAP_NUMFUNCS) {
|
|
ASSERT(!HDR_SHARED_DATA(hdr));
|
|
ASSERT3U(bswap, <, DMU_BSWAP_NUMFUNCS);
|
|
dmu_ot_byteswap[bswap].ob_func(buf->b_data, HDR_GET_LSIZE(hdr));
|
|
}
|
|
|
|
/* Compute the hdr's checksum if necessary */
|
|
arc_cksum_compute(buf);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* If this function is being called to decrypt an encrypted buffer or verify an
|
|
* authenticated one, the key must be loaded and a mapping must be made
|
|
* available in the keystore via spa_keystore_create_mapping() or one of its
|
|
* callers.
|
|
*/
|
|
int
|
|
arc_untransform(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb,
|
|
boolean_t in_place)
|
|
{
|
|
int ret;
|
|
arc_fill_flags_t flags = 0;
|
|
|
|
if (in_place)
|
|
flags |= ARC_FILL_IN_PLACE;
|
|
|
|
ret = arc_buf_fill(buf, spa, zb, flags);
|
|
if (ret == ECKSUM) {
|
|
/*
|
|
* Convert authentication and decryption errors to EIO
|
|
* (and generate an ereport) before leaving the ARC.
|
|
*/
|
|
ret = SET_ERROR(EIO);
|
|
spa_log_error(spa, zb);
|
|
zfs_ereport_post(FM_EREPORT_ZFS_AUTHENTICATION,
|
|
spa, NULL, zb, NULL, 0, 0);
|
|
}
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Increment the amount of evictable space in the arc_state_t's refcount.
|
|
* We account for the space used by the hdr and the arc buf individually
|
|
* so that we can add and remove them from the refcount individually.
|
|
*/
|
|
static void
|
|
arc_evictable_space_increment(arc_buf_hdr_t *hdr, arc_state_t *state)
|
|
{
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
if (GHOST_STATE(state)) {
|
|
ASSERT0(hdr->b_l1hdr.b_bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
(void) zfs_refcount_add_many(&state->arcs_esize[type],
|
|
HDR_GET_LSIZE(hdr), hdr);
|
|
return;
|
|
}
|
|
|
|
ASSERT(!GHOST_STATE(state));
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
(void) zfs_refcount_add_many(&state->arcs_esize[type],
|
|
arc_hdr_size(hdr), hdr);
|
|
}
|
|
if (HDR_HAS_RABD(hdr)) {
|
|
(void) zfs_refcount_add_many(&state->arcs_esize[type],
|
|
HDR_GET_PSIZE(hdr), hdr);
|
|
}
|
|
|
|
for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL;
|
|
buf = buf->b_next) {
|
|
if (arc_buf_is_shared(buf))
|
|
continue;
|
|
(void) zfs_refcount_add_many(&state->arcs_esize[type],
|
|
arc_buf_size(buf), buf);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Decrement the amount of evictable space in the arc_state_t's refcount.
|
|
* We account for the space used by the hdr and the arc buf individually
|
|
* so that we can add and remove them from the refcount individually.
|
|
*/
|
|
static void
|
|
arc_evictable_space_decrement(arc_buf_hdr_t *hdr, arc_state_t *state)
|
|
{
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
if (GHOST_STATE(state)) {
|
|
ASSERT0(hdr->b_l1hdr.b_bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
HDR_GET_LSIZE(hdr), hdr);
|
|
return;
|
|
}
|
|
|
|
ASSERT(!GHOST_STATE(state));
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
arc_hdr_size(hdr), hdr);
|
|
}
|
|
if (HDR_HAS_RABD(hdr)) {
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
HDR_GET_PSIZE(hdr), hdr);
|
|
}
|
|
|
|
for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL;
|
|
buf = buf->b_next) {
|
|
if (arc_buf_is_shared(buf))
|
|
continue;
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
arc_buf_size(buf), buf);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Add a reference to this hdr indicating that someone is actively
|
|
* referencing that memory. When the refcount transitions from 0 to 1,
|
|
* we remove it from the respective arc_state_t list to indicate that
|
|
* it is not evictable.
|
|
*/
|
|
static void
|
|
add_reference(arc_buf_hdr_t *hdr, void *tag)
|
|
{
|
|
arc_state_t *state;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
if (!HDR_EMPTY(hdr) && !MUTEX_HELD(HDR_LOCK(hdr))) {
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_anon);
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
}
|
|
|
|
state = hdr->b_l1hdr.b_state;
|
|
|
|
if ((zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag) == 1) &&
|
|
(state != arc_anon)) {
|
|
/* We don't use the L2-only state list. */
|
|
if (state != arc_l2c_only) {
|
|
multilist_remove(state->arcs_list[arc_buf_type(hdr)],
|
|
hdr);
|
|
arc_evictable_space_decrement(hdr, state);
|
|
}
|
|
/* remove the prefetch flag if we get a reference */
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_PREFETCH);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove a reference from this hdr. When the reference transitions from
|
|
* 1 to 0 and we're not anonymous, then we add this hdr to the arc_state_t's
|
|
* list making it eligible for eviction.
|
|
*/
|
|
static int
|
|
remove_reference(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, void *tag)
|
|
{
|
|
int cnt;
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(state == arc_anon || MUTEX_HELD(hash_lock));
|
|
ASSERT(!GHOST_STATE(state));
|
|
|
|
/*
|
|
* arc_l2c_only counts as a ghost state so we don't need to explicitly
|
|
* check to prevent usage of the arc_l2c_only list.
|
|
*/
|
|
if (((cnt = zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag)) == 0) &&
|
|
(state != arc_anon)) {
|
|
multilist_insert(state->arcs_list[arc_buf_type(hdr)], hdr);
|
|
ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0);
|
|
arc_evictable_space_increment(hdr, state);
|
|
}
|
|
return (cnt);
|
|
}
|
|
|
|
/*
|
|
* Returns detailed information about a specific arc buffer. When the
|
|
* state_index argument is set the function will calculate the arc header
|
|
* list position for its arc state. Since this requires a linear traversal
|
|
* callers are strongly encourage not to do this. However, it can be helpful
|
|
* for targeted analysis so the functionality is provided.
|
|
*/
|
|
void
|
|
arc_buf_info(arc_buf_t *ab, arc_buf_info_t *abi, int state_index)
|
|
{
|
|
arc_buf_hdr_t *hdr = ab->b_hdr;
|
|
l1arc_buf_hdr_t *l1hdr = NULL;
|
|
l2arc_buf_hdr_t *l2hdr = NULL;
|
|
arc_state_t *state = NULL;
|
|
|
|
memset(abi, 0, sizeof (arc_buf_info_t));
|
|
|
|
if (hdr == NULL)
|
|
return;
|
|
|
|
abi->abi_flags = hdr->b_flags;
|
|
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
l1hdr = &hdr->b_l1hdr;
|
|
state = l1hdr->b_state;
|
|
}
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
l2hdr = &hdr->b_l2hdr;
|
|
|
|
if (l1hdr) {
|
|
abi->abi_bufcnt = l1hdr->b_bufcnt;
|
|
abi->abi_access = l1hdr->b_arc_access;
|
|
abi->abi_mru_hits = l1hdr->b_mru_hits;
|
|
abi->abi_mru_ghost_hits = l1hdr->b_mru_ghost_hits;
|
|
abi->abi_mfu_hits = l1hdr->b_mfu_hits;
|
|
abi->abi_mfu_ghost_hits = l1hdr->b_mfu_ghost_hits;
|
|
abi->abi_holds = zfs_refcount_count(&l1hdr->b_refcnt);
|
|
}
|
|
|
|
if (l2hdr) {
|
|
abi->abi_l2arc_dattr = l2hdr->b_daddr;
|
|
abi->abi_l2arc_hits = l2hdr->b_hits;
|
|
}
|
|
|
|
abi->abi_state_type = state ? state->arcs_state : ARC_STATE_ANON;
|
|
abi->abi_state_contents = arc_buf_type(hdr);
|
|
abi->abi_size = arc_hdr_size(hdr);
|
|
}
|
|
|
|
/*
|
|
* Move the supplied buffer to the indicated state. The hash lock
|
|
* for the buffer must be held by the caller.
|
|
*/
|
|
static void
|
|
arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *hdr,
|
|
kmutex_t *hash_lock)
|
|
{
|
|
arc_state_t *old_state;
|
|
int64_t refcnt;
|
|
uint32_t bufcnt;
|
|
boolean_t update_old, update_new;
|
|
arc_buf_contents_t buftype = arc_buf_type(hdr);
|
|
|
|
/*
|
|
* We almost always have an L1 hdr here, since we call arc_hdr_realloc()
|
|
* in arc_read() when bringing a buffer out of the L2ARC. However, the
|
|
* L1 hdr doesn't always exist when we change state to arc_anon before
|
|
* destroying a header, in which case reallocating to add the L1 hdr is
|
|
* pointless.
|
|
*/
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
old_state = hdr->b_l1hdr.b_state;
|
|
refcnt = zfs_refcount_count(&hdr->b_l1hdr.b_refcnt);
|
|
bufcnt = hdr->b_l1hdr.b_bufcnt;
|
|
update_old = (bufcnt > 0 || hdr->b_l1hdr.b_pabd != NULL ||
|
|
HDR_HAS_RABD(hdr));
|
|
} else {
|
|
old_state = arc_l2c_only;
|
|
refcnt = 0;
|
|
bufcnt = 0;
|
|
update_old = B_FALSE;
|
|
}
|
|
update_new = update_old;
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT3P(new_state, !=, old_state);
|
|
ASSERT(!GHOST_STATE(new_state) || bufcnt == 0);
|
|
ASSERT(old_state != arc_anon || bufcnt <= 1);
|
|
|
|
/*
|
|
* If this buffer is evictable, transfer it from the
|
|
* old state list to the new state list.
|
|
*/
|
|
if (refcnt == 0) {
|
|
if (old_state != arc_anon && old_state != arc_l2c_only) {
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
multilist_remove(old_state->arcs_list[buftype], hdr);
|
|
|
|
if (GHOST_STATE(old_state)) {
|
|
ASSERT0(bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
update_old = B_TRUE;
|
|
}
|
|
arc_evictable_space_decrement(hdr, old_state);
|
|
}
|
|
if (new_state != arc_anon && new_state != arc_l2c_only) {
|
|
/*
|
|
* An L1 header always exists here, since if we're
|
|
* moving to some L1-cached state (i.e. not l2c_only or
|
|
* anonymous), we realloc the header to add an L1hdr
|
|
* beforehand.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
multilist_insert(new_state->arcs_list[buftype], hdr);
|
|
|
|
if (GHOST_STATE(new_state)) {
|
|
ASSERT0(bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
update_new = B_TRUE;
|
|
}
|
|
arc_evictable_space_increment(hdr, new_state);
|
|
}
|
|
}
|
|
|
|
ASSERT(!HDR_EMPTY(hdr));
|
|
if (new_state == arc_anon && HDR_IN_HASH_TABLE(hdr))
|
|
buf_hash_remove(hdr);
|
|
|
|
/* adjust state sizes (ignore arc_l2c_only) */
|
|
|
|
if (update_new && new_state != arc_l2c_only) {
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
if (GHOST_STATE(new_state)) {
|
|
ASSERT0(bufcnt);
|
|
|
|
/*
|
|
* When moving a header to a ghost state, we first
|
|
* remove all arc buffers. Thus, we'll have a
|
|
* bufcnt of zero, and no arc buffer to use for
|
|
* the reference. As a result, we use the arc
|
|
* header pointer for the reference.
|
|
*/
|
|
(void) zfs_refcount_add_many(&new_state->arcs_size,
|
|
HDR_GET_LSIZE(hdr), hdr);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
} else {
|
|
uint32_t buffers = 0;
|
|
|
|
/*
|
|
* Each individual buffer holds a unique reference,
|
|
* thus we must remove each of these references one
|
|
* at a time.
|
|
*/
|
|
for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL;
|
|
buf = buf->b_next) {
|
|
ASSERT3U(bufcnt, !=, 0);
|
|
buffers++;
|
|
|
|
/*
|
|
* When the arc_buf_t is sharing the data
|
|
* block with the hdr, the owner of the
|
|
* reference belongs to the hdr. Only
|
|
* add to the refcount if the arc_buf_t is
|
|
* not shared.
|
|
*/
|
|
if (arc_buf_is_shared(buf))
|
|
continue;
|
|
|
|
(void) zfs_refcount_add_many(
|
|
&new_state->arcs_size,
|
|
arc_buf_size(buf), buf);
|
|
}
|
|
ASSERT3U(bufcnt, ==, buffers);
|
|
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
(void) zfs_refcount_add_many(
|
|
&new_state->arcs_size,
|
|
arc_hdr_size(hdr), hdr);
|
|
}
|
|
|
|
if (HDR_HAS_RABD(hdr)) {
|
|
(void) zfs_refcount_add_many(
|
|
&new_state->arcs_size,
|
|
HDR_GET_PSIZE(hdr), hdr);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (update_old && old_state != arc_l2c_only) {
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
if (GHOST_STATE(old_state)) {
|
|
ASSERT0(bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
|
|
/*
|
|
* When moving a header off of a ghost state,
|
|
* the header will not contain any arc buffers.
|
|
* We use the arc header pointer for the reference
|
|
* which is exactly what we did when we put the
|
|
* header on the ghost state.
|
|
*/
|
|
|
|
(void) zfs_refcount_remove_many(&old_state->arcs_size,
|
|
HDR_GET_LSIZE(hdr), hdr);
|
|
} else {
|
|
uint32_t buffers = 0;
|
|
|
|
/*
|
|
* Each individual buffer holds a unique reference,
|
|
* thus we must remove each of these references one
|
|
* at a time.
|
|
*/
|
|
for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL;
|
|
buf = buf->b_next) {
|
|
ASSERT3U(bufcnt, !=, 0);
|
|
buffers++;
|
|
|
|
/*
|
|
* When the arc_buf_t is sharing the data
|
|
* block with the hdr, the owner of the
|
|
* reference belongs to the hdr. Only
|
|
* add to the refcount if the arc_buf_t is
|
|
* not shared.
|
|
*/
|
|
if (arc_buf_is_shared(buf))
|
|
continue;
|
|
|
|
(void) zfs_refcount_remove_many(
|
|
&old_state->arcs_size, arc_buf_size(buf),
|
|
buf);
|
|
}
|
|
ASSERT3U(bufcnt, ==, buffers);
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL ||
|
|
HDR_HAS_RABD(hdr));
|
|
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
(void) zfs_refcount_remove_many(
|
|
&old_state->arcs_size, arc_hdr_size(hdr),
|
|
hdr);
|
|
}
|
|
|
|
if (HDR_HAS_RABD(hdr)) {
|
|
(void) zfs_refcount_remove_many(
|
|
&old_state->arcs_size, HDR_GET_PSIZE(hdr),
|
|
hdr);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (HDR_HAS_L1HDR(hdr))
|
|
hdr->b_l1hdr.b_state = new_state;
|
|
|
|
/*
|
|
* L2 headers should never be on the L2 state list since they don't
|
|
* have L1 headers allocated.
|
|
*/
|
|
ASSERT(multilist_is_empty(arc_l2c_only->arcs_list[ARC_BUFC_DATA]) &&
|
|
multilist_is_empty(arc_l2c_only->arcs_list[ARC_BUFC_METADATA]));
|
|
}
|
|
|
|
void
|
|
arc_space_consume(uint64_t space, arc_space_type_t type)
|
|
{
|
|
ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES);
|
|
|
|
switch (type) {
|
|
default:
|
|
break;
|
|
case ARC_SPACE_DATA:
|
|
aggsum_add(&astat_data_size, space);
|
|
break;
|
|
case ARC_SPACE_META:
|
|
aggsum_add(&astat_metadata_size, space);
|
|
break;
|
|
case ARC_SPACE_BONUS:
|
|
aggsum_add(&astat_bonus_size, space);
|
|
break;
|
|
case ARC_SPACE_DNODE:
|
|
aggsum_add(&astat_dnode_size, space);
|
|
break;
|
|
case ARC_SPACE_DBUF:
|
|
aggsum_add(&astat_dbuf_size, space);
|
|
break;
|
|
case ARC_SPACE_HDRS:
|
|
aggsum_add(&astat_hdr_size, space);
|
|
break;
|
|
case ARC_SPACE_L2HDRS:
|
|
aggsum_add(&astat_l2_hdr_size, space);
|
|
break;
|
|
case ARC_SPACE_ABD_CHUNK_WASTE:
|
|
/*
|
|
* Note: this includes space wasted by all scatter ABD's, not
|
|
* just those allocated by the ARC. But the vast majority of
|
|
* scatter ABD's come from the ARC, because other users are
|
|
* very short-lived.
|
|
*/
|
|
aggsum_add(&astat_abd_chunk_waste_size, space);
|
|
break;
|
|
}
|
|
|
|
if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_CHUNK_WASTE)
|
|
aggsum_add(&arc_meta_used, space);
|
|
|
|
aggsum_add(&arc_size, space);
|
|
}
|
|
|
|
void
|
|
arc_space_return(uint64_t space, arc_space_type_t type)
|
|
{
|
|
ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES);
|
|
|
|
switch (type) {
|
|
default:
|
|
break;
|
|
case ARC_SPACE_DATA:
|
|
aggsum_add(&astat_data_size, -space);
|
|
break;
|
|
case ARC_SPACE_META:
|
|
aggsum_add(&astat_metadata_size, -space);
|
|
break;
|
|
case ARC_SPACE_BONUS:
|
|
aggsum_add(&astat_bonus_size, -space);
|
|
break;
|
|
case ARC_SPACE_DNODE:
|
|
aggsum_add(&astat_dnode_size, -space);
|
|
break;
|
|
case ARC_SPACE_DBUF:
|
|
aggsum_add(&astat_dbuf_size, -space);
|
|
break;
|
|
case ARC_SPACE_HDRS:
|
|
aggsum_add(&astat_hdr_size, -space);
|
|
break;
|
|
case ARC_SPACE_L2HDRS:
|
|
aggsum_add(&astat_l2_hdr_size, -space);
|
|
break;
|
|
case ARC_SPACE_ABD_CHUNK_WASTE:
|
|
aggsum_add(&astat_abd_chunk_waste_size, -space);
|
|
break;
|
|
}
|
|
|
|
if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_CHUNK_WASTE) {
|
|
ASSERT(aggsum_compare(&arc_meta_used, space) >= 0);
|
|
/*
|
|
* We use the upper bound here rather than the precise value
|
|
* because the arc_meta_max value doesn't need to be
|
|
* precise. It's only consumed by humans via arcstats.
|
|
*/
|
|
if (arc_meta_max < aggsum_upper_bound(&arc_meta_used))
|
|
arc_meta_max = aggsum_upper_bound(&arc_meta_used);
|
|
aggsum_add(&arc_meta_used, -space);
|
|
}
|
|
|
|
ASSERT(aggsum_compare(&arc_size, space) >= 0);
|
|
aggsum_add(&arc_size, -space);
|
|
}
|
|
|
|
/*
|
|
* Given a hdr and a buf, returns whether that buf can share its b_data buffer
|
|
* with the hdr's b_pabd.
|
|
*/
|
|
static boolean_t
|
|
arc_can_share(arc_buf_hdr_t *hdr, arc_buf_t *buf)
|
|
{
|
|
/*
|
|
* The criteria for sharing a hdr's data are:
|
|
* 1. the buffer is not encrypted
|
|
* 2. the hdr's compression matches the buf's compression
|
|
* 3. the hdr doesn't need to be byteswapped
|
|
* 4. the hdr isn't already being shared
|
|
* 5. the buf is either compressed or it is the last buf in the hdr list
|
|
*
|
|
* Criterion #5 maintains the invariant that shared uncompressed
|
|
* bufs must be the final buf in the hdr's b_buf list. Reading this, you
|
|
* might ask, "if a compressed buf is allocated first, won't that be the
|
|
* last thing in the list?", but in that case it's impossible to create
|
|
* a shared uncompressed buf anyway (because the hdr must be compressed
|
|
* to have the compressed buf). You might also think that #3 is
|
|
* sufficient to make this guarantee, however it's possible
|
|
* (specifically in the rare L2ARC write race mentioned in
|
|
* arc_buf_alloc_impl()) there will be an existing uncompressed buf that
|
|
* is shareable, but wasn't at the time of its allocation. Rather than
|
|
* allow a new shared uncompressed buf to be created and then shuffle
|
|
* the list around to make it the last element, this simply disallows
|
|
* sharing if the new buf isn't the first to be added.
|
|
*/
|
|
ASSERT3P(buf->b_hdr, ==, hdr);
|
|
boolean_t hdr_compressed =
|
|
arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF;
|
|
boolean_t buf_compressed = ARC_BUF_COMPRESSED(buf) != 0;
|
|
return (!ARC_BUF_ENCRYPTED(buf) &&
|
|
buf_compressed == hdr_compressed &&
|
|
hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS &&
|
|
!HDR_SHARED_DATA(hdr) &&
|
|
(ARC_BUF_LAST(buf) || ARC_BUF_COMPRESSED(buf)));
|
|
}
|
|
|
|
/*
|
|
* Allocate a buf for this hdr. If you care about the data that's in the hdr,
|
|
* or if you want a compressed buffer, pass those flags in. Returns 0 if the
|
|
* copy was made successfully, or an error code otherwise.
|
|
*/
|
|
static int
|
|
arc_buf_alloc_impl(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb,
|
|
void *tag, boolean_t encrypted, boolean_t compressed, boolean_t noauth,
|
|
boolean_t fill, arc_buf_t **ret)
|
|
{
|
|
arc_buf_t *buf;
|
|
arc_fill_flags_t flags = ARC_FILL_LOCKED;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), >, 0);
|
|
VERIFY(hdr->b_type == ARC_BUFC_DATA ||
|
|
hdr->b_type == ARC_BUFC_METADATA);
|
|
ASSERT3P(ret, !=, NULL);
|
|
ASSERT3P(*ret, ==, NULL);
|
|
IMPLY(encrypted, compressed);
|
|
|
|
hdr->b_l1hdr.b_mru_hits = 0;
|
|
hdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_l2_hits = 0;
|
|
|
|
buf = *ret = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
|
|
buf->b_hdr = hdr;
|
|
buf->b_data = NULL;
|
|
buf->b_next = hdr->b_l1hdr.b_buf;
|
|
buf->b_flags = 0;
|
|
|
|
add_reference(hdr, tag);
|
|
|
|
/*
|
|
* We're about to change the hdr's b_flags. We must either
|
|
* hold the hash_lock or be undiscoverable.
|
|
*/
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
/*
|
|
* Only honor requests for compressed bufs if the hdr is actually
|
|
* compressed. This must be overridden if the buffer is encrypted since
|
|
* encrypted buffers cannot be decompressed.
|
|
*/
|
|
if (encrypted) {
|
|
buf->b_flags |= ARC_BUF_FLAG_COMPRESSED;
|
|
buf->b_flags |= ARC_BUF_FLAG_ENCRYPTED;
|
|
flags |= ARC_FILL_COMPRESSED | ARC_FILL_ENCRYPTED;
|
|
} else if (compressed &&
|
|
arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) {
|
|
buf->b_flags |= ARC_BUF_FLAG_COMPRESSED;
|
|
flags |= ARC_FILL_COMPRESSED;
|
|
}
|
|
|
|
if (noauth) {
|
|
ASSERT0(encrypted);
|
|
flags |= ARC_FILL_NOAUTH;
|
|
}
|
|
|
|
/*
|
|
* If the hdr's data can be shared then we share the data buffer and
|
|
* set the appropriate bit in the hdr's b_flags to indicate the hdr is
|
|
* sharing it's b_pabd with the arc_buf_t. Otherwise, we allocate a new
|
|
* buffer to store the buf's data.
|
|
*
|
|
* There are two additional restrictions here because we're sharing
|
|
* hdr -> buf instead of the usual buf -> hdr. First, the hdr can't be
|
|
* actively involved in an L2ARC write, because if this buf is used by
|
|
* an arc_write() then the hdr's data buffer will be released when the
|
|
* write completes, even though the L2ARC write might still be using it.
|
|
* Second, the hdr's ABD must be linear so that the buf's user doesn't
|
|
* need to be ABD-aware. It must be allocated via
|
|
* zio_[data_]buf_alloc(), not as a page, because we need to be able
|
|
* to abd_release_ownership_of_buf(), which isn't allowed on "linear
|
|
* page" buffers because the ABD code needs to handle freeing them
|
|
* specially.
|
|
*/
|
|
boolean_t can_share = arc_can_share(hdr, buf) &&
|
|
!HDR_L2_WRITING(hdr) &&
|
|
hdr->b_l1hdr.b_pabd != NULL &&
|
|
abd_is_linear(hdr->b_l1hdr.b_pabd) &&
|
|
!abd_is_linear_page(hdr->b_l1hdr.b_pabd);
|
|
|
|
/* Set up b_data and sharing */
|
|
if (can_share) {
|
|
buf->b_data = abd_to_buf(hdr->b_l1hdr.b_pabd);
|
|
buf->b_flags |= ARC_BUF_FLAG_SHARED;
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA);
|
|
} else {
|
|
buf->b_data =
|
|
arc_get_data_buf(hdr, arc_buf_size(buf), buf);
|
|
ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf));
|
|
}
|
|
VERIFY3P(buf->b_data, !=, NULL);
|
|
|
|
hdr->b_l1hdr.b_buf = buf;
|
|
hdr->b_l1hdr.b_bufcnt += 1;
|
|
if (encrypted)
|
|
hdr->b_crypt_hdr.b_ebufcnt += 1;
|
|
|
|
/*
|
|
* If the user wants the data from the hdr, we need to either copy or
|
|
* decompress the data.
|
|
*/
|
|
if (fill) {
|
|
ASSERT3P(zb, !=, NULL);
|
|
return (arc_buf_fill(buf, spa, zb, flags));
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
static char *arc_onloan_tag = "onloan";
|
|
|
|
static inline void
|
|
arc_loaned_bytes_update(int64_t delta)
|
|
{
|
|
atomic_add_64(&arc_loaned_bytes, delta);
|
|
|
|
/* assert that it did not wrap around */
|
|
ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0);
|
|
}
|
|
|
|
/*
|
|
* Loan out an anonymous arc buffer. Loaned buffers are not counted as in
|
|
* flight data by arc_tempreserve_space() until they are "returned". Loaned
|
|
* buffers must be returned to the arc before they can be used by the DMU or
|
|
* freed.
|
|
*/
|
|
arc_buf_t *
|
|
arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size)
|
|
{
|
|
arc_buf_t *buf = arc_alloc_buf(spa, arc_onloan_tag,
|
|
is_metadata ? ARC_BUFC_METADATA : ARC_BUFC_DATA, size);
|
|
|
|
arc_loaned_bytes_update(arc_buf_size(buf));
|
|
|
|
return (buf);
|
|
}
|
|
|
|
arc_buf_t *
|
|
arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
|
|
enum zio_compress compression_type, uint8_t complevel)
|
|
{
|
|
arc_buf_t *buf = arc_alloc_compressed_buf(spa, arc_onloan_tag,
|
|
psize, lsize, compression_type, complevel);
|
|
|
|
arc_loaned_bytes_update(arc_buf_size(buf));
|
|
|
|
return (buf);
|
|
}
|
|
|
|
arc_buf_t *
|
|
arc_loan_raw_buf(spa_t *spa, uint64_t dsobj, boolean_t byteorder,
|
|
const uint8_t *salt, const uint8_t *iv, const uint8_t *mac,
|
|
dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
|
|
enum zio_compress compression_type, uint8_t complevel)
|
|
{
|
|
arc_buf_t *buf = arc_alloc_raw_buf(spa, arc_onloan_tag, dsobj,
|
|
byteorder, salt, iv, mac, ot, psize, lsize, compression_type,
|
|
complevel);
|
|
|
|
atomic_add_64(&arc_loaned_bytes, psize);
|
|
return (buf);
|
|
}
|
|
|
|
|
|
/*
|
|
* Return a loaned arc buffer to the arc.
|
|
*/
|
|
void
|
|
arc_return_buf(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT3P(buf->b_data, !=, NULL);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
(void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag);
|
|
(void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag);
|
|
|
|
arc_loaned_bytes_update(-arc_buf_size(buf));
|
|
}
|
|
|
|
/* Detach an arc_buf from a dbuf (tag) */
|
|
void
|
|
arc_loan_inuse_buf(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT3P(buf->b_data, !=, NULL);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
(void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag);
|
|
(void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag);
|
|
|
|
arc_loaned_bytes_update(arc_buf_size(buf));
|
|
}
|
|
|
|
static void
|
|
l2arc_free_abd_on_write(abd_t *abd, size_t size, arc_buf_contents_t type)
|
|
{
|
|
l2arc_data_free_t *df = kmem_alloc(sizeof (*df), KM_SLEEP);
|
|
|
|
df->l2df_abd = abd;
|
|
df->l2df_size = size;
|
|
df->l2df_type = type;
|
|
mutex_enter(&l2arc_free_on_write_mtx);
|
|
list_insert_head(l2arc_free_on_write, df);
|
|
mutex_exit(&l2arc_free_on_write_mtx);
|
|
}
|
|
|
|
static void
|
|
arc_hdr_free_on_write(arc_buf_hdr_t *hdr, boolean_t free_rdata)
|
|
{
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr);
|
|
|
|
/* protected by hash lock, if in the hash table */
|
|
if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) {
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT(state != arc_anon && state != arc_l2c_only);
|
|
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
size, hdr);
|
|
}
|
|
(void) zfs_refcount_remove_many(&state->arcs_size, size, hdr);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
arc_space_return(size, ARC_SPACE_META);
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
arc_space_return(size, ARC_SPACE_DATA);
|
|
}
|
|
|
|
if (free_rdata) {
|
|
l2arc_free_abd_on_write(hdr->b_crypt_hdr.b_rabd, size, type);
|
|
} else {
|
|
l2arc_free_abd_on_write(hdr->b_l1hdr.b_pabd, size, type);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Share the arc_buf_t's data with the hdr. Whenever we are sharing the
|
|
* data buffer, we transfer the refcount ownership to the hdr and update
|
|
* the appropriate kstats.
|
|
*/
|
|
static void
|
|
arc_share_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf)
|
|
{
|
|
ASSERT(arc_can_share(hdr, buf));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!ARC_BUF_ENCRYPTED(buf));
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
/*
|
|
* Start sharing the data buffer. We transfer the
|
|
* refcount ownership to the hdr since it always owns
|
|
* the refcount whenever an arc_buf_t is shared.
|
|
*/
|
|
zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size,
|
|
arc_hdr_size(hdr), buf, hdr);
|
|
hdr->b_l1hdr.b_pabd = abd_get_from_buf(buf->b_data, arc_buf_size(buf));
|
|
abd_take_ownership_of_buf(hdr->b_l1hdr.b_pabd,
|
|
HDR_ISTYPE_METADATA(hdr));
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA);
|
|
buf->b_flags |= ARC_BUF_FLAG_SHARED;
|
|
|
|
/*
|
|
* Since we've transferred ownership to the hdr we need
|
|
* to increment its compressed and uncompressed kstats and
|
|
* decrement the overhead size.
|
|
*/
|
|
ARCSTAT_INCR(arcstat_compressed_size, arc_hdr_size(hdr));
|
|
ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr));
|
|
ARCSTAT_INCR(arcstat_overhead_size, -arc_buf_size(buf));
|
|
}
|
|
|
|
static void
|
|
arc_unshare_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf)
|
|
{
|
|
ASSERT(arc_buf_is_shared(buf));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
/*
|
|
* We are no longer sharing this buffer so we need
|
|
* to transfer its ownership to the rightful owner.
|
|
*/
|
|
zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size,
|
|
arc_hdr_size(hdr), hdr, buf);
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA);
|
|
abd_release_ownership_of_buf(hdr->b_l1hdr.b_pabd);
|
|
abd_put(hdr->b_l1hdr.b_pabd);
|
|
hdr->b_l1hdr.b_pabd = NULL;
|
|
buf->b_flags &= ~ARC_BUF_FLAG_SHARED;
|
|
|
|
/*
|
|
* Since the buffer is no longer shared between
|
|
* the arc buf and the hdr, count it as overhead.
|
|
*/
|
|
ARCSTAT_INCR(arcstat_compressed_size, -arc_hdr_size(hdr));
|
|
ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr));
|
|
ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf));
|
|
}
|
|
|
|
/*
|
|
* Remove an arc_buf_t from the hdr's buf list and return the last
|
|
* arc_buf_t on the list. If no buffers remain on the list then return
|
|
* NULL.
|
|
*/
|
|
static arc_buf_t *
|
|
arc_buf_remove(arc_buf_hdr_t *hdr, arc_buf_t *buf)
|
|
{
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
arc_buf_t **bufp = &hdr->b_l1hdr.b_buf;
|
|
arc_buf_t *lastbuf = NULL;
|
|
|
|
/*
|
|
* Remove the buf from the hdr list and locate the last
|
|
* remaining buffer on the list.
|
|
*/
|
|
while (*bufp != NULL) {
|
|
if (*bufp == buf)
|
|
*bufp = buf->b_next;
|
|
|
|
/*
|
|
* If we've removed a buffer in the middle of
|
|
* the list then update the lastbuf and update
|
|
* bufp.
|
|
*/
|
|
if (*bufp != NULL) {
|
|
lastbuf = *bufp;
|
|
bufp = &(*bufp)->b_next;
|
|
}
|
|
}
|
|
buf->b_next = NULL;
|
|
ASSERT3P(lastbuf, !=, buf);
|
|
IMPLY(hdr->b_l1hdr.b_bufcnt > 0, lastbuf != NULL);
|
|
IMPLY(hdr->b_l1hdr.b_bufcnt > 0, hdr->b_l1hdr.b_buf != NULL);
|
|
IMPLY(lastbuf != NULL, ARC_BUF_LAST(lastbuf));
|
|
|
|
return (lastbuf);
|
|
}
|
|
|
|
/*
|
|
* Free up buf->b_data and pull the arc_buf_t off of the arc_buf_hdr_t's
|
|
* list and free it.
|
|
*/
|
|
static void
|
|
arc_buf_destroy_impl(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
/*
|
|
* Free up the data associated with the buf but only if we're not
|
|
* sharing this with the hdr. If we are sharing it with the hdr, the
|
|
* hdr is responsible for doing the free.
|
|
*/
|
|
if (buf->b_data != NULL) {
|
|
/*
|
|
* We're about to change the hdr's b_flags. We must either
|
|
* hold the hash_lock or be undiscoverable.
|
|
*/
|
|
ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
|
|
|
|
arc_cksum_verify(buf);
|
|
arc_buf_unwatch(buf);
|
|
|
|
if (arc_buf_is_shared(buf)) {
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA);
|
|
} else {
|
|
uint64_t size = arc_buf_size(buf);
|
|
arc_free_data_buf(hdr, buf->b_data, size, buf);
|
|
ARCSTAT_INCR(arcstat_overhead_size, -size);
|
|
}
|
|
buf->b_data = NULL;
|
|
|
|
ASSERT(hdr->b_l1hdr.b_bufcnt > 0);
|
|
hdr->b_l1hdr.b_bufcnt -= 1;
|
|
|
|
if (ARC_BUF_ENCRYPTED(buf)) {
|
|
hdr->b_crypt_hdr.b_ebufcnt -= 1;
|
|
|
|
/*
|
|
* If we have no more encrypted buffers and we've
|
|
* already gotten a copy of the decrypted data we can
|
|
* free b_rabd to save some space.
|
|
*/
|
|
if (hdr->b_crypt_hdr.b_ebufcnt == 0 &&
|
|
HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd != NULL &&
|
|
!HDR_IO_IN_PROGRESS(hdr)) {
|
|
arc_hdr_free_abd(hdr, B_TRUE);
|
|
}
|
|
}
|
|
}
|
|
|
|
arc_buf_t *lastbuf = arc_buf_remove(hdr, buf);
|
|
|
|
if (ARC_BUF_SHARED(buf) && !ARC_BUF_COMPRESSED(buf)) {
|
|
/*
|
|
* If the current arc_buf_t is sharing its data buffer with the
|
|
* hdr, then reassign the hdr's b_pabd to share it with the new
|
|
* buffer at the end of the list. The shared buffer is always
|
|
* the last one on the hdr's buffer list.
|
|
*
|
|
* There is an equivalent case for compressed bufs, but since
|
|
* they aren't guaranteed to be the last buf in the list and
|
|
* that is an exceedingly rare case, we just allow that space be
|
|
* wasted temporarily. We must also be careful not to share
|
|
* encrypted buffers, since they cannot be shared.
|
|
*/
|
|
if (lastbuf != NULL && !ARC_BUF_ENCRYPTED(lastbuf)) {
|
|
/* Only one buf can be shared at once */
|
|
VERIFY(!arc_buf_is_shared(lastbuf));
|
|
/* hdr is uncompressed so can't have compressed buf */
|
|
VERIFY(!ARC_BUF_COMPRESSED(lastbuf));
|
|
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
|
|
/*
|
|
* We must setup a new shared block between the
|
|
* last buffer and the hdr. The data would have
|
|
* been allocated by the arc buf so we need to transfer
|
|
* ownership to the hdr since it's now being shared.
|
|
*/
|
|
arc_share_buf(hdr, lastbuf);
|
|
}
|
|
} else if (HDR_SHARED_DATA(hdr)) {
|
|
/*
|
|
* Uncompressed shared buffers are always at the end
|
|
* of the list. Compressed buffers don't have the
|
|
* same requirements. This makes it hard to
|
|
* simply assert that the lastbuf is shared so
|
|
* we rely on the hdr's compression flags to determine
|
|
* if we have a compressed, shared buffer.
|
|
*/
|
|
ASSERT3P(lastbuf, !=, NULL);
|
|
ASSERT(arc_buf_is_shared(lastbuf) ||
|
|
arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF);
|
|
}
|
|
|
|
/*
|
|
* Free the checksum if we're removing the last uncompressed buf from
|
|
* this hdr.
|
|
*/
|
|
if (!arc_hdr_has_uncompressed_buf(hdr)) {
|
|
arc_cksum_free(hdr);
|
|
}
|
|
|
|
/* clean up the buf */
|
|
buf->b_hdr = NULL;
|
|
kmem_cache_free(buf_cache, buf);
|
|
}
|
|
|
|
static void
|
|
arc_hdr_alloc_abd(arc_buf_hdr_t *hdr, int alloc_flags)
|
|
{
|
|
uint64_t size;
|
|
boolean_t alloc_rdata = ((alloc_flags & ARC_HDR_ALLOC_RDATA) != 0);
|
|
boolean_t do_adapt = ((alloc_flags & ARC_HDR_DO_ADAPT) != 0);
|
|
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), >, 0);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(!HDR_SHARED_DATA(hdr) || alloc_rdata);
|
|
IMPLY(alloc_rdata, HDR_PROTECTED(hdr));
|
|
|
|
if (alloc_rdata) {
|
|
size = HDR_GET_PSIZE(hdr);
|
|
ASSERT3P(hdr->b_crypt_hdr.b_rabd, ==, NULL);
|
|
hdr->b_crypt_hdr.b_rabd = arc_get_data_abd(hdr, size, hdr,
|
|
do_adapt);
|
|
ASSERT3P(hdr->b_crypt_hdr.b_rabd, !=, NULL);
|
|
ARCSTAT_INCR(arcstat_raw_size, size);
|
|
} else {
|
|
size = arc_hdr_size(hdr);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
hdr->b_l1hdr.b_pabd = arc_get_data_abd(hdr, size, hdr,
|
|
do_adapt);
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
}
|
|
|
|
ARCSTAT_INCR(arcstat_compressed_size, size);
|
|
ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr));
|
|
}
|
|
|
|
static void
|
|
arc_hdr_free_abd(arc_buf_hdr_t *hdr, boolean_t free_rdata)
|
|
{
|
|
uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr));
|
|
IMPLY(free_rdata, HDR_HAS_RABD(hdr));
|
|
|
|
/*
|
|
* If the hdr is currently being written to the l2arc then
|
|
* we defer freeing the data by adding it to the l2arc_free_on_write
|
|
* list. The l2arc will free the data once it's finished
|
|
* writing it to the l2arc device.
|
|
*/
|
|
if (HDR_L2_WRITING(hdr)) {
|
|
arc_hdr_free_on_write(hdr, free_rdata);
|
|
ARCSTAT_BUMP(arcstat_l2_free_on_write);
|
|
} else if (free_rdata) {
|
|
arc_free_data_abd(hdr, hdr->b_crypt_hdr.b_rabd, size, hdr);
|
|
} else {
|
|
arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, size, hdr);
|
|
}
|
|
|
|
if (free_rdata) {
|
|
hdr->b_crypt_hdr.b_rabd = NULL;
|
|
ARCSTAT_INCR(arcstat_raw_size, -size);
|
|
} else {
|
|
hdr->b_l1hdr.b_pabd = NULL;
|
|
}
|
|
|
|
if (hdr->b_l1hdr.b_pabd == NULL && !HDR_HAS_RABD(hdr))
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS;
|
|
|
|
ARCSTAT_INCR(arcstat_compressed_size, -size);
|
|
ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr));
|
|
}
|
|
|
|
static arc_buf_hdr_t *
|
|
arc_hdr_alloc(uint64_t spa, int32_t psize, int32_t lsize,
|
|
boolean_t protected, enum zio_compress compression_type, uint8_t complevel,
|
|
arc_buf_contents_t type, boolean_t alloc_rdata)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
int flags = ARC_HDR_DO_ADAPT;
|
|
|
|
VERIFY(type == ARC_BUFC_DATA || type == ARC_BUFC_METADATA);
|
|
if (protected) {
|
|
hdr = kmem_cache_alloc(hdr_full_crypt_cache, KM_PUSHPAGE);
|
|
} else {
|
|
hdr = kmem_cache_alloc(hdr_full_cache, KM_PUSHPAGE);
|
|
}
|
|
flags |= alloc_rdata ? ARC_HDR_ALLOC_RDATA : 0;
|
|
|
|
ASSERT(HDR_EMPTY(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL);
|
|
HDR_SET_PSIZE(hdr, psize);
|
|
HDR_SET_LSIZE(hdr, lsize);
|
|
hdr->b_spa = spa;
|
|
hdr->b_type = type;
|
|
hdr->b_flags = 0;
|
|
arc_hdr_set_flags(hdr, arc_bufc_to_flags(type) | ARC_FLAG_HAS_L1HDR);
|
|
arc_hdr_set_compress(hdr, compression_type);
|
|
hdr->b_complevel = complevel;
|
|
if (protected)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PROTECTED);
|
|
|
|
hdr->b_l1hdr.b_state = arc_anon;
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
hdr->b_l1hdr.b_bufcnt = 0;
|
|
hdr->b_l1hdr.b_buf = NULL;
|
|
|
|
/*
|
|
* Allocate the hdr's buffer. This will contain either
|
|
* the compressed or uncompressed data depending on the block
|
|
* it references and compressed arc enablement.
|
|
*/
|
|
arc_hdr_alloc_abd(hdr, flags);
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
|
|
return (hdr);
|
|
}
|
|
|
|
/*
|
|
* Transition between the two allocation states for the arc_buf_hdr struct.
|
|
* The arc_buf_hdr struct can be allocated with (hdr_full_cache) or without
|
|
* (hdr_l2only_cache) the fields necessary for the L1 cache - the smaller
|
|
* version is used when a cache buffer is only in the L2ARC in order to reduce
|
|
* memory usage.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
arc_hdr_realloc(arc_buf_hdr_t *hdr, kmem_cache_t *old, kmem_cache_t *new)
|
|
{
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
arc_buf_hdr_t *nhdr;
|
|
l2arc_dev_t *dev = hdr->b_l2hdr.b_dev;
|
|
|
|
ASSERT((old == hdr_full_cache && new == hdr_l2only_cache) ||
|
|
(old == hdr_l2only_cache && new == hdr_full_cache));
|
|
|
|
/*
|
|
* if the caller wanted a new full header and the header is to be
|
|
* encrypted we will actually allocate the header from the full crypt
|
|
* cache instead. The same applies to freeing from the old cache.
|
|
*/
|
|
if (HDR_PROTECTED(hdr) && new == hdr_full_cache)
|
|
new = hdr_full_crypt_cache;
|
|
if (HDR_PROTECTED(hdr) && old == hdr_full_cache)
|
|
old = hdr_full_crypt_cache;
|
|
|
|
nhdr = kmem_cache_alloc(new, KM_PUSHPAGE);
|
|
|
|
ASSERT(MUTEX_HELD(HDR_LOCK(hdr)));
|
|
buf_hash_remove(hdr);
|
|
|
|
bcopy(hdr, nhdr, HDR_L2ONLY_SIZE);
|
|
|
|
if (new == hdr_full_cache || new == hdr_full_crypt_cache) {
|
|
arc_hdr_set_flags(nhdr, ARC_FLAG_HAS_L1HDR);
|
|
/*
|
|
* arc_access and arc_change_state need to be aware that a
|
|
* header has just come out of L2ARC, so we set its state to
|
|
* l2c_only even though it's about to change.
|
|
*/
|
|
nhdr->b_l1hdr.b_state = arc_l2c_only;
|
|
|
|
/* Verify previous threads set to NULL before freeing */
|
|
ASSERT3P(nhdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
} else {
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
ASSERT0(hdr->b_l1hdr.b_bufcnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL);
|
|
|
|
/*
|
|
* If we've reached here, We must have been called from
|
|
* arc_evict_hdr(), as such we should have already been
|
|
* removed from any ghost list we were previously on
|
|
* (which protects us from racing with arc_evict_state),
|
|
* thus no locking is needed during this check.
|
|
*/
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
|
|
/*
|
|
* A buffer must not be moved into the arc_l2c_only
|
|
* state if it's not finished being written out to the
|
|
* l2arc device. Otherwise, the b_l1hdr.b_pabd field
|
|
* might try to be accessed, even though it was removed.
|
|
*/
|
|
VERIFY(!HDR_L2_WRITING(hdr));
|
|
VERIFY3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
|
|
arc_hdr_clear_flags(nhdr, ARC_FLAG_HAS_L1HDR);
|
|
}
|
|
/*
|
|
* The header has been reallocated so we need to re-insert it into any
|
|
* lists it was on.
|
|
*/
|
|
(void) buf_hash_insert(nhdr, NULL);
|
|
|
|
ASSERT(list_link_active(&hdr->b_l2hdr.b_l2node));
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We must place the realloc'ed header back into the list at
|
|
* the same spot. Otherwise, if it's placed earlier in the list,
|
|
* l2arc_write_buffers() could find it during the function's
|
|
* write phase, and try to write it out to the l2arc.
|
|
*/
|
|
list_insert_after(&dev->l2ad_buflist, hdr, nhdr);
|
|
list_remove(&dev->l2ad_buflist, hdr);
|
|
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Since we're using the pointer address as the tag when
|
|
* incrementing and decrementing the l2ad_alloc refcount, we
|
|
* must remove the old pointer (that we're about to destroy) and
|
|
* add the new pointer to the refcount. Otherwise we'd remove
|
|
* the wrong pointer address when calling arc_hdr_destroy() later.
|
|
*/
|
|
|
|
(void) zfs_refcount_remove_many(&dev->l2ad_alloc,
|
|
arc_hdr_size(hdr), hdr);
|
|
(void) zfs_refcount_add_many(&dev->l2ad_alloc,
|
|
arc_hdr_size(nhdr), nhdr);
|
|
|
|
buf_discard_identity(hdr);
|
|
kmem_cache_free(old, hdr);
|
|
|
|
return (nhdr);
|
|
}
|
|
|
|
/*
|
|
* This function allows an L1 header to be reallocated as a crypt
|
|
* header and vice versa. If we are going to a crypt header, the
|
|
* new fields will be zeroed out.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
arc_hdr_realloc_crypt(arc_buf_hdr_t *hdr, boolean_t need_crypt)
|
|
{
|
|
arc_buf_hdr_t *nhdr;
|
|
arc_buf_t *buf;
|
|
kmem_cache_t *ncache, *ocache;
|
|
unsigned nsize, osize;
|
|
|
|
/*
|
|
* This function requires that hdr is in the arc_anon state.
|
|
* Therefore it won't have any L2ARC data for us to worry
|
|
* about copying.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(!HDR_HAS_L2HDR(hdr));
|
|
ASSERT3U(!!HDR_PROTECTED(hdr), !=, need_crypt);
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
ASSERT(!list_link_active(&hdr->b_l2hdr.b_l2node));
|
|
ASSERT3P(hdr->b_hash_next, ==, NULL);
|
|
|
|
if (need_crypt) {
|
|
ncache = hdr_full_crypt_cache;
|
|
nsize = sizeof (hdr->b_crypt_hdr);
|
|
ocache = hdr_full_cache;
|
|
osize = HDR_FULL_SIZE;
|
|
} else {
|
|
ncache = hdr_full_cache;
|
|
nsize = HDR_FULL_SIZE;
|
|
ocache = hdr_full_crypt_cache;
|
|
osize = sizeof (hdr->b_crypt_hdr);
|
|
}
|
|
|
|
nhdr = kmem_cache_alloc(ncache, KM_PUSHPAGE);
|
|
|
|
/*
|
|
* Copy all members that aren't locks or condvars to the new header.
|
|
* No lists are pointing to us (as we asserted above), so we don't
|
|
* need to worry about the list nodes.
|
|
*/
|
|
nhdr->b_dva = hdr->b_dva;
|
|
nhdr->b_birth = hdr->b_birth;
|
|
nhdr->b_type = hdr->b_type;
|
|
nhdr->b_flags = hdr->b_flags;
|
|
nhdr->b_psize = hdr->b_psize;
|
|
nhdr->b_lsize = hdr->b_lsize;
|
|
nhdr->b_spa = hdr->b_spa;
|
|
nhdr->b_l1hdr.b_freeze_cksum = hdr->b_l1hdr.b_freeze_cksum;
|
|
nhdr->b_l1hdr.b_bufcnt = hdr->b_l1hdr.b_bufcnt;
|
|
nhdr->b_l1hdr.b_byteswap = hdr->b_l1hdr.b_byteswap;
|
|
nhdr->b_l1hdr.b_state = hdr->b_l1hdr.b_state;
|
|
nhdr->b_l1hdr.b_arc_access = hdr->b_l1hdr.b_arc_access;
|
|
nhdr->b_l1hdr.b_mru_hits = hdr->b_l1hdr.b_mru_hits;
|
|
nhdr->b_l1hdr.b_mru_ghost_hits = hdr->b_l1hdr.b_mru_ghost_hits;
|
|
nhdr->b_l1hdr.b_mfu_hits = hdr->b_l1hdr.b_mfu_hits;
|
|
nhdr->b_l1hdr.b_mfu_ghost_hits = hdr->b_l1hdr.b_mfu_ghost_hits;
|
|
nhdr->b_l1hdr.b_l2_hits = hdr->b_l1hdr.b_l2_hits;
|
|
nhdr->b_l1hdr.b_acb = hdr->b_l1hdr.b_acb;
|
|
nhdr->b_l1hdr.b_pabd = hdr->b_l1hdr.b_pabd;
|
|
|
|
/*
|
|
* This zfs_refcount_add() exists only to ensure that the individual
|
|
* arc buffers always point to a header that is referenced, avoiding
|
|
* a small race condition that could trigger ASSERTs.
|
|
*/
|
|
(void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, FTAG);
|
|
nhdr->b_l1hdr.b_buf = hdr->b_l1hdr.b_buf;
|
|
for (buf = nhdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) {
|
|
mutex_enter(&buf->b_evict_lock);
|
|
buf->b_hdr = nhdr;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
}
|
|
|
|
zfs_refcount_transfer(&nhdr->b_l1hdr.b_refcnt, &hdr->b_l1hdr.b_refcnt);
|
|
(void) zfs_refcount_remove(&nhdr->b_l1hdr.b_refcnt, FTAG);
|
|
ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt));
|
|
|
|
if (need_crypt) {
|
|
arc_hdr_set_flags(nhdr, ARC_FLAG_PROTECTED);
|
|
} else {
|
|
arc_hdr_clear_flags(nhdr, ARC_FLAG_PROTECTED);
|
|
}
|
|
|
|
/* unset all members of the original hdr */
|
|
bzero(&hdr->b_dva, sizeof (dva_t));
|
|
hdr->b_birth = 0;
|
|
hdr->b_type = ARC_BUFC_INVALID;
|
|
hdr->b_flags = 0;
|
|
hdr->b_psize = 0;
|
|
hdr->b_lsize = 0;
|
|
hdr->b_spa = 0;
|
|
hdr->b_l1hdr.b_freeze_cksum = NULL;
|
|
hdr->b_l1hdr.b_buf = NULL;
|
|
hdr->b_l1hdr.b_bufcnt = 0;
|
|
hdr->b_l1hdr.b_byteswap = 0;
|
|
hdr->b_l1hdr.b_state = NULL;
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
hdr->b_l1hdr.b_mru_hits = 0;
|
|
hdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_l2_hits = 0;
|
|
hdr->b_l1hdr.b_acb = NULL;
|
|
hdr->b_l1hdr.b_pabd = NULL;
|
|
|
|
if (ocache == hdr_full_crypt_cache) {
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
hdr->b_crypt_hdr.b_ot = DMU_OT_NONE;
|
|
hdr->b_crypt_hdr.b_ebufcnt = 0;
|
|
hdr->b_crypt_hdr.b_dsobj = 0;
|
|
bzero(hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN);
|
|
bzero(hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN);
|
|
bzero(hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN);
|
|
}
|
|
|
|
buf_discard_identity(hdr);
|
|
kmem_cache_free(ocache, hdr);
|
|
|
|
return (nhdr);
|
|
}
|
|
|
|
/*
|
|
* This function is used by the send / receive code to convert a newly
|
|
* allocated arc_buf_t to one that is suitable for a raw encrypted write. It
|
|
* is also used to allow the root objset block to be updated without altering
|
|
* its embedded MACs. Both block types will always be uncompressed so we do not
|
|
* have to worry about compression type or psize.
|
|
*/
|
|
void
|
|
arc_convert_to_raw(arc_buf_t *buf, uint64_t dsobj, boolean_t byteorder,
|
|
dmu_object_type_t ot, const uint8_t *salt, const uint8_t *iv,
|
|
const uint8_t *mac)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(ot == DMU_OT_DNODE || ot == DMU_OT_OBJSET);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
|
|
buf->b_flags |= (ARC_BUF_FLAG_COMPRESSED | ARC_BUF_FLAG_ENCRYPTED);
|
|
if (!HDR_PROTECTED(hdr))
|
|
hdr = arc_hdr_realloc_crypt(hdr, B_TRUE);
|
|
hdr->b_crypt_hdr.b_dsobj = dsobj;
|
|
hdr->b_crypt_hdr.b_ot = ot;
|
|
hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ?
|
|
DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot);
|
|
if (!arc_hdr_has_uncompressed_buf(hdr))
|
|
arc_cksum_free(hdr);
|
|
|
|
if (salt != NULL)
|
|
bcopy(salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN);
|
|
if (iv != NULL)
|
|
bcopy(iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN);
|
|
if (mac != NULL)
|
|
bcopy(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN);
|
|
}
|
|
|
|
/*
|
|
* Allocate a new arc_buf_hdr_t and arc_buf_t and return the buf to the caller.
|
|
* The buf is returned thawed since we expect the consumer to modify it.
|
|
*/
|
|
arc_buf_t *
|
|
arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type, int32_t size)
|
|
{
|
|
arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), size, size,
|
|
B_FALSE, ZIO_COMPRESS_OFF, 0, type, B_FALSE);
|
|
|
|
arc_buf_t *buf = NULL;
|
|
VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE, B_FALSE,
|
|
B_FALSE, B_FALSE, &buf));
|
|
arc_buf_thaw(buf);
|
|
|
|
return (buf);
|
|
}
|
|
|
|
/*
|
|
* Allocate a compressed buf in the same manner as arc_alloc_buf. Don't use this
|
|
* for bufs containing metadata.
|
|
*/
|
|
arc_buf_t *
|
|
arc_alloc_compressed_buf(spa_t *spa, void *tag, uint64_t psize, uint64_t lsize,
|
|
enum zio_compress compression_type, uint8_t complevel)
|
|
{
|
|
ASSERT3U(lsize, >, 0);
|
|
ASSERT3U(lsize, >=, psize);
|
|
ASSERT3U(compression_type, >, ZIO_COMPRESS_OFF);
|
|
ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS);
|
|
|
|
arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize,
|
|
B_FALSE, compression_type, complevel, ARC_BUFC_DATA, B_FALSE);
|
|
|
|
arc_buf_t *buf = NULL;
|
|
VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE,
|
|
B_TRUE, B_FALSE, B_FALSE, &buf));
|
|
arc_buf_thaw(buf);
|
|
ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL);
|
|
|
|
if (!arc_buf_is_shared(buf)) {
|
|
/*
|
|
* To ensure that the hdr has the correct data in it if we call
|
|
* arc_untransform() on this buf before it's been written to
|
|
* disk, it's easiest if we just set up sharing between the
|
|
* buf and the hdr.
|
|
*/
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
arc_share_buf(hdr, buf);
|
|
}
|
|
|
|
return (buf);
|
|
}
|
|
|
|
arc_buf_t *
|
|
arc_alloc_raw_buf(spa_t *spa, void *tag, uint64_t dsobj, boolean_t byteorder,
|
|
const uint8_t *salt, const uint8_t *iv, const uint8_t *mac,
|
|
dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
|
|
enum zio_compress compression_type, uint8_t complevel)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
arc_buf_t *buf;
|
|
arc_buf_contents_t type = DMU_OT_IS_METADATA(ot) ?
|
|
ARC_BUFC_METADATA : ARC_BUFC_DATA;
|
|
|
|
ASSERT3U(lsize, >, 0);
|
|
ASSERT3U(lsize, >=, psize);
|
|
ASSERT3U(compression_type, >=, ZIO_COMPRESS_OFF);
|
|
ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS);
|
|
|
|
hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, B_TRUE,
|
|
compression_type, complevel, type, B_TRUE);
|
|
|
|
hdr->b_crypt_hdr.b_dsobj = dsobj;
|
|
hdr->b_crypt_hdr.b_ot = ot;
|
|
hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ?
|
|
DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot);
|
|
bcopy(salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN);
|
|
bcopy(iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN);
|
|
bcopy(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN);
|
|
|
|
/*
|
|
* This buffer will be considered encrypted even if the ot is not an
|
|
* encrypted type. It will become authenticated instead in
|
|
* arc_write_ready().
|
|
*/
|
|
buf = NULL;
|
|
VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_TRUE, B_TRUE,
|
|
B_FALSE, B_FALSE, &buf));
|
|
arc_buf_thaw(buf);
|
|
ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL);
|
|
|
|
return (buf);
|
|
}
|
|
|
|
static void
|
|
arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr)
|
|
{
|
|
l2arc_buf_hdr_t *l2hdr = &hdr->b_l2hdr;
|
|
l2arc_dev_t *dev = l2hdr->b_dev;
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, psize);
|
|
|
|
ASSERT(MUTEX_HELD(&dev->l2ad_mtx));
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
list_remove(&dev->l2ad_buflist, hdr);
|
|
|
|
ARCSTAT_INCR(arcstat_l2_psize, -psize);
|
|
ARCSTAT_INCR(arcstat_l2_lsize, -HDR_GET_LSIZE(hdr));
|
|
|
|
vdev_space_update(dev->l2ad_vdev, -asize, 0, 0);
|
|
|
|
(void) zfs_refcount_remove_many(&dev->l2ad_alloc, arc_hdr_size(hdr),
|
|
hdr);
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR);
|
|
}
|
|
|
|
static void
|
|
arc_hdr_destroy(arc_buf_hdr_t *hdr)
|
|
{
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL ||
|
|
hdr->b_l1hdr.b_bufcnt > 0);
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
}
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
l2arc_dev_t *dev = hdr->b_l2hdr.b_dev;
|
|
boolean_t buflist_held = MUTEX_HELD(&dev->l2ad_mtx);
|
|
|
|
if (!buflist_held)
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Even though we checked this conditional above, we
|
|
* need to check this again now that we have the
|
|
* l2ad_mtx. This is because we could be racing with
|
|
* another thread calling l2arc_evict() which might have
|
|
* destroyed this header's L2 portion as we were waiting
|
|
* to acquire the l2ad_mtx. If that happens, we don't
|
|
* want to re-destroy the header's L2 portion.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
|
|
if (!buflist_held)
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
}
|
|
|
|
/*
|
|
* The header's identify can only be safely discarded once it is no
|
|
* longer discoverable. This requires removing it from the hash table
|
|
* and the l2arc header list. After this point the hash lock can not
|
|
* be used to protect the header.
|
|
*/
|
|
if (!HDR_EMPTY(hdr))
|
|
buf_discard_identity(hdr);
|
|
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
arc_cksum_free(hdr);
|
|
|
|
while (hdr->b_l1hdr.b_buf != NULL)
|
|
arc_buf_destroy_impl(hdr->b_l1hdr.b_buf);
|
|
|
|
if (hdr->b_l1hdr.b_pabd != NULL)
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
|
|
if (HDR_HAS_RABD(hdr))
|
|
arc_hdr_free_abd(hdr, B_TRUE);
|
|
}
|
|
|
|
ASSERT3P(hdr->b_hash_next, ==, NULL);
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL);
|
|
|
|
if (!HDR_PROTECTED(hdr)) {
|
|
kmem_cache_free(hdr_full_cache, hdr);
|
|
} else {
|
|
kmem_cache_free(hdr_full_crypt_cache, hdr);
|
|
}
|
|
} else {
|
|
kmem_cache_free(hdr_l2only_cache, hdr);
|
|
}
|
|
}
|
|
|
|
void
|
|
arc_buf_destroy(arc_buf_t *buf, void* tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1);
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
VERIFY0(remove_reference(hdr, NULL, tag));
|
|
arc_hdr_destroy(hdr);
|
|
return;
|
|
}
|
|
|
|
kmutex_t *hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
|
|
ASSERT3P(hdr, ==, buf->b_hdr);
|
|
ASSERT(hdr->b_l1hdr.b_bufcnt > 0);
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_state, !=, arc_anon);
|
|
ASSERT3P(buf->b_data, !=, NULL);
|
|
|
|
(void) remove_reference(hdr, hash_lock, tag);
|
|
arc_buf_destroy_impl(buf);
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
/*
|
|
* Evict the arc_buf_hdr that is provided as a parameter. The resultant
|
|
* state of the header is dependent on its state prior to entering this
|
|
* function. The following transitions are possible:
|
|
*
|
|
* - arc_mru -> arc_mru_ghost
|
|
* - arc_mfu -> arc_mfu_ghost
|
|
* - arc_mru_ghost -> arc_l2c_only
|
|
* - arc_mru_ghost -> deleted
|
|
* - arc_mfu_ghost -> arc_l2c_only
|
|
* - arc_mfu_ghost -> deleted
|
|
*/
|
|
static int64_t
|
|
arc_evict_hdr(arc_buf_hdr_t *hdr, kmutex_t *hash_lock)
|
|
{
|
|
arc_state_t *evicted_state, *state;
|
|
int64_t bytes_evicted = 0;
|
|
int min_lifetime = HDR_PRESCIENT_PREFETCH(hdr) ?
|
|
arc_min_prescient_prefetch_ms : arc_min_prefetch_ms;
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
state = hdr->b_l1hdr.b_state;
|
|
if (GHOST_STATE(state)) {
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
|
|
/*
|
|
* l2arc_write_buffers() relies on a header's L1 portion
|
|
* (i.e. its b_pabd field) during it's write phase.
|
|
* Thus, we cannot push a header onto the arc_l2c_only
|
|
* state (removing its L1 piece) until the header is
|
|
* done being written to the l2arc.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr) && HDR_L2_WRITING(hdr)) {
|
|
ARCSTAT_BUMP(arcstat_evict_l2_skip);
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_deleted);
|
|
bytes_evicted += HDR_GET_LSIZE(hdr);
|
|
|
|
DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, hdr);
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
ASSERT(hdr->b_l1hdr.b_pabd == NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
/*
|
|
* This buffer is cached on the 2nd Level ARC;
|
|
* don't destroy the header.
|
|
*/
|
|
arc_change_state(arc_l2c_only, hdr, hash_lock);
|
|
/*
|
|
* dropping from L1+L2 cached to L2-only,
|
|
* realloc to remove the L1 header.
|
|
*/
|
|
hdr = arc_hdr_realloc(hdr, hdr_full_cache,
|
|
hdr_l2only_cache);
|
|
} else {
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
arc_hdr_destroy(hdr);
|
|
}
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ASSERT(state == arc_mru || state == arc_mfu);
|
|
evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost;
|
|
|
|
/* prefetch buffers have a minimum lifespan */
|
|
if (HDR_IO_IN_PROGRESS(hdr) ||
|
|
((hdr->b_flags & (ARC_FLAG_PREFETCH | ARC_FLAG_INDIRECT)) &&
|
|
ddi_get_lbolt() - hdr->b_l1hdr.b_arc_access <
|
|
MSEC_TO_TICK(min_lifetime))) {
|
|
ARCSTAT_BUMP(arcstat_evict_skip);
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt));
|
|
while (hdr->b_l1hdr.b_buf) {
|
|
arc_buf_t *buf = hdr->b_l1hdr.b_buf;
|
|
if (!mutex_tryenter(&buf->b_evict_lock)) {
|
|
ARCSTAT_BUMP(arcstat_mutex_miss);
|
|
break;
|
|
}
|
|
if (buf->b_data != NULL)
|
|
bytes_evicted += HDR_GET_LSIZE(hdr);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
arc_buf_destroy_impl(buf);
|
|
}
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
ARCSTAT_INCR(arcstat_evict_l2_cached, HDR_GET_LSIZE(hdr));
|
|
} else {
|
|
if (l2arc_write_eligible(hdr->b_spa, hdr)) {
|
|
ARCSTAT_INCR(arcstat_evict_l2_eligible,
|
|
HDR_GET_LSIZE(hdr));
|
|
} else {
|
|
ARCSTAT_INCR(arcstat_evict_l2_ineligible,
|
|
HDR_GET_LSIZE(hdr));
|
|
}
|
|
}
|
|
|
|
if (hdr->b_l1hdr.b_bufcnt == 0) {
|
|
arc_cksum_free(hdr);
|
|
|
|
bytes_evicted += arc_hdr_size(hdr);
|
|
|
|
/*
|
|
* If this hdr is being evicted and has a compressed
|
|
* buffer then we discard it here before we change states.
|
|
* This ensures that the accounting is updated correctly
|
|
* in arc_free_data_impl().
|
|
*/
|
|
if (hdr->b_l1hdr.b_pabd != NULL)
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
|
|
if (HDR_HAS_RABD(hdr))
|
|
arc_hdr_free_abd(hdr, B_TRUE);
|
|
|
|
arc_change_state(evicted_state, hdr, hash_lock);
|
|
ASSERT(HDR_IN_HASH_TABLE(hdr));
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE);
|
|
DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, hdr);
|
|
}
|
|
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
static void
|
|
arc_set_need_free(void)
|
|
{
|
|
ASSERT(MUTEX_HELD(&arc_evict_lock));
|
|
int64_t remaining = arc_free_memory() - arc_sys_free / 2;
|
|
arc_evict_waiter_t *aw = list_tail(&arc_evict_waiters);
|
|
if (aw == NULL) {
|
|
arc_need_free = MAX(-remaining, 0);
|
|
} else {
|
|
arc_need_free =
|
|
MAX(-remaining, (int64_t)(aw->aew_count - arc_evict_count));
|
|
}
|
|
}
|
|
|
|
static uint64_t
|
|
arc_evict_state_impl(multilist_t *ml, int idx, arc_buf_hdr_t *marker,
|
|
uint64_t spa, int64_t bytes)
|
|
{
|
|
multilist_sublist_t *mls;
|
|
uint64_t bytes_evicted = 0;
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
int evict_count = 0;
|
|
|
|
ASSERT3P(marker, !=, NULL);
|
|
IMPLY(bytes < 0, bytes == ARC_EVICT_ALL);
|
|
|
|
mls = multilist_sublist_lock(ml, idx);
|
|
|
|
for (hdr = multilist_sublist_prev(mls, marker); hdr != NULL;
|
|
hdr = multilist_sublist_prev(mls, marker)) {
|
|
if ((bytes != ARC_EVICT_ALL && bytes_evicted >= bytes) ||
|
|
(evict_count >= zfs_arc_evict_batch_limit))
|
|
break;
|
|
|
|
/*
|
|
* To keep our iteration location, move the marker
|
|
* forward. Since we're not holding hdr's hash lock, we
|
|
* must be very careful and not remove 'hdr' from the
|
|
* sublist. Otherwise, other consumers might mistake the
|
|
* 'hdr' as not being on a sublist when they call the
|
|
* multilist_link_active() function (they all rely on
|
|
* the hash lock protecting concurrent insertions and
|
|
* removals). multilist_sublist_move_forward() was
|
|
* specifically implemented to ensure this is the case
|
|
* (only 'marker' will be removed and re-inserted).
|
|
*/
|
|
multilist_sublist_move_forward(mls, marker);
|
|
|
|
/*
|
|
* The only case where the b_spa field should ever be
|
|
* zero, is the marker headers inserted by
|
|
* arc_evict_state(). It's possible for multiple threads
|
|
* to be calling arc_evict_state() concurrently (e.g.
|
|
* dsl_pool_close() and zio_inject_fault()), so we must
|
|
* skip any markers we see from these other threads.
|
|
*/
|
|
if (hdr->b_spa == 0)
|
|
continue;
|
|
|
|
/* we're only interested in evicting buffers of a certain spa */
|
|
if (spa != 0 && hdr->b_spa != spa) {
|
|
ARCSTAT_BUMP(arcstat_evict_skip);
|
|
continue;
|
|
}
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We aren't calling this function from any code path
|
|
* that would already be holding a hash lock, so we're
|
|
* asserting on this assumption to be defensive in case
|
|
* this ever changes. Without this check, it would be
|
|
* possible to incorrectly increment arcstat_mutex_miss
|
|
* below (e.g. if the code changed such that we called
|
|
* this function with a hash lock held).
|
|
*/
|
|
ASSERT(!MUTEX_HELD(hash_lock));
|
|
|
|
if (mutex_tryenter(hash_lock)) {
|
|
uint64_t evicted = arc_evict_hdr(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
|
|
bytes_evicted += evicted;
|
|
|
|
/*
|
|
* If evicted is zero, arc_evict_hdr() must have
|
|
* decided to skip this header, don't increment
|
|
* evict_count in this case.
|
|
*/
|
|
if (evicted != 0)
|
|
evict_count++;
|
|
|
|
} else {
|
|
ARCSTAT_BUMP(arcstat_mutex_miss);
|
|
}
|
|
}
|
|
|
|
multilist_sublist_unlock(mls);
|
|
|
|
/*
|
|
* Increment the count of evicted bytes, and wake up any threads that
|
|
* are waiting for the count to reach this value. Since the list is
|
|
* ordered by ascending aew_count, we pop off the beginning of the
|
|
* list until we reach the end, or a waiter that's past the current
|
|
* "count". Doing this outside the loop reduces the number of times
|
|
* we need to acquire the global arc_evict_lock.
|
|
*
|
|
* Only wake when there's sufficient free memory in the system
|
|
* (specifically, arc_sys_free/2, which by default is a bit more than
|
|
* 1/64th of RAM). See the comments in arc_wait_for_eviction().
|
|
*/
|
|
mutex_enter(&arc_evict_lock);
|
|
arc_evict_count += bytes_evicted;
|
|
|
|
if ((int64_t)(arc_free_memory() - arc_sys_free / 2) > 0) {
|
|
arc_evict_waiter_t *aw;
|
|
while ((aw = list_head(&arc_evict_waiters)) != NULL &&
|
|
aw->aew_count <= arc_evict_count) {
|
|
list_remove(&arc_evict_waiters, aw);
|
|
cv_broadcast(&aw->aew_cv);
|
|
}
|
|
}
|
|
arc_set_need_free();
|
|
mutex_exit(&arc_evict_lock);
|
|
|
|
/*
|
|
* If the ARC size is reduced from arc_c_max to arc_c_min (especially
|
|
* if the average cached block is small), eviction can be on-CPU for
|
|
* many seconds. To ensure that other threads that may be bound to
|
|
* this CPU are able to make progress, make a voluntary preemption
|
|
* call here.
|
|
*/
|
|
cond_resched();
|
|
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the given arc state, until we've removed the
|
|
* specified number of bytes. Move the removed buffers to the
|
|
* appropriate evict state.
|
|
*
|
|
* This function makes a "best effort". It skips over any buffers
|
|
* it can't get a hash_lock on, and so, may not catch all candidates.
|
|
* It may also return without evicting as much space as requested.
|
|
*
|
|
* If bytes is specified using the special value ARC_EVICT_ALL, this
|
|
* will evict all available (i.e. unlocked and evictable) buffers from
|
|
* the given arc state; which is used by arc_flush().
|
|
*/
|
|
static uint64_t
|
|
arc_evict_state(arc_state_t *state, uint64_t spa, int64_t bytes,
|
|
arc_buf_contents_t type)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
multilist_t *ml = state->arcs_list[type];
|
|
int num_sublists;
|
|
arc_buf_hdr_t **markers;
|
|
|
|
IMPLY(bytes < 0, bytes == ARC_EVICT_ALL);
|
|
|
|
num_sublists = multilist_get_num_sublists(ml);
|
|
|
|
/*
|
|
* If we've tried to evict from each sublist, made some
|
|
* progress, but still have not hit the target number of bytes
|
|
* to evict, we want to keep trying. The markers allow us to
|
|
* pick up where we left off for each individual sublist, rather
|
|
* than starting from the tail each time.
|
|
*/
|
|
markers = kmem_zalloc(sizeof (*markers) * num_sublists, KM_SLEEP);
|
|
for (int i = 0; i < num_sublists; i++) {
|
|
multilist_sublist_t *mls;
|
|
|
|
markers[i] = kmem_cache_alloc(hdr_full_cache, KM_SLEEP);
|
|
|
|
/*
|
|
* A b_spa of 0 is used to indicate that this header is
|
|
* a marker. This fact is used in arc_evict_type() and
|
|
* arc_evict_state_impl().
|
|
*/
|
|
markers[i]->b_spa = 0;
|
|
|
|
mls = multilist_sublist_lock(ml, i);
|
|
multilist_sublist_insert_tail(mls, markers[i]);
|
|
multilist_sublist_unlock(mls);
|
|
}
|
|
|
|
/*
|
|
* While we haven't hit our target number of bytes to evict, or
|
|
* we're evicting all available buffers.
|
|
*/
|
|
while (total_evicted < bytes || bytes == ARC_EVICT_ALL) {
|
|
int sublist_idx = multilist_get_random_index(ml);
|
|
uint64_t scan_evicted = 0;
|
|
|
|
/*
|
|
* Try to reduce pinned dnodes with a floor of arc_dnode_limit.
|
|
* Request that 10% of the LRUs be scanned by the superblock
|
|
* shrinker.
|
|
*/
|
|
if (type == ARC_BUFC_DATA && aggsum_compare(&astat_dnode_size,
|
|
arc_dnode_size_limit) > 0) {
|
|
arc_prune_async((aggsum_upper_bound(&astat_dnode_size) -
|
|
arc_dnode_size_limit) / sizeof (dnode_t) /
|
|
zfs_arc_dnode_reduce_percent);
|
|
}
|
|
|
|
/*
|
|
* Start eviction using a randomly selected sublist,
|
|
* this is to try and evenly balance eviction across all
|
|
* sublists. Always starting at the same sublist
|
|
* (e.g. index 0) would cause evictions to favor certain
|
|
* sublists over others.
|
|
*/
|
|
for (int i = 0; i < num_sublists; i++) {
|
|
uint64_t bytes_remaining;
|
|
uint64_t bytes_evicted;
|
|
|
|
if (bytes == ARC_EVICT_ALL)
|
|
bytes_remaining = ARC_EVICT_ALL;
|
|
else if (total_evicted < bytes)
|
|
bytes_remaining = bytes - total_evicted;
|
|
else
|
|
break;
|
|
|
|
bytes_evicted = arc_evict_state_impl(ml, sublist_idx,
|
|
markers[sublist_idx], spa, bytes_remaining);
|
|
|
|
scan_evicted += bytes_evicted;
|
|
total_evicted += bytes_evicted;
|
|
|
|
/* we've reached the end, wrap to the beginning */
|
|
if (++sublist_idx >= num_sublists)
|
|
sublist_idx = 0;
|
|
}
|
|
|
|
/*
|
|
* If we didn't evict anything during this scan, we have
|
|
* no reason to believe we'll evict more during another
|
|
* scan, so break the loop.
|
|
*/
|
|
if (scan_evicted == 0) {
|
|
/* This isn't possible, let's make that obvious */
|
|
ASSERT3S(bytes, !=, 0);
|
|
|
|
/*
|
|
* When bytes is ARC_EVICT_ALL, the only way to
|
|
* break the loop is when scan_evicted is zero.
|
|
* In that case, we actually have evicted enough,
|
|
* so we don't want to increment the kstat.
|
|
*/
|
|
if (bytes != ARC_EVICT_ALL) {
|
|
ASSERT3S(total_evicted, <, bytes);
|
|
ARCSTAT_BUMP(arcstat_evict_not_enough);
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
for (int i = 0; i < num_sublists; i++) {
|
|
multilist_sublist_t *mls = multilist_sublist_lock(ml, i);
|
|
multilist_sublist_remove(mls, markers[i]);
|
|
multilist_sublist_unlock(mls);
|
|
|
|
kmem_cache_free(hdr_full_cache, markers[i]);
|
|
}
|
|
kmem_free(markers, sizeof (*markers) * num_sublists);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
/*
|
|
* Flush all "evictable" data of the given type from the arc state
|
|
* specified. This will not evict any "active" buffers (i.e. referenced).
|
|
*
|
|
* When 'retry' is set to B_FALSE, the function will make a single pass
|
|
* over the state and evict any buffers that it can. Since it doesn't
|
|
* continually retry the eviction, it might end up leaving some buffers
|
|
* in the ARC due to lock misses.
|
|
*
|
|
* When 'retry' is set to B_TRUE, the function will continually retry the
|
|
* eviction until *all* evictable buffers have been removed from the
|
|
* state. As a result, if concurrent insertions into the state are
|
|
* allowed (e.g. if the ARC isn't shutting down), this function might
|
|
* wind up in an infinite loop, continually trying to evict buffers.
|
|
*/
|
|
static uint64_t
|
|
arc_flush_state(arc_state_t *state, uint64_t spa, arc_buf_contents_t type,
|
|
boolean_t retry)
|
|
{
|
|
uint64_t evicted = 0;
|
|
|
|
while (zfs_refcount_count(&state->arcs_esize[type]) != 0) {
|
|
evicted += arc_evict_state(state, spa, ARC_EVICT_ALL, type);
|
|
|
|
if (!retry)
|
|
break;
|
|
}
|
|
|
|
return (evicted);
|
|
}
|
|
|
|
/*
|
|
* Evict the specified number of bytes from the state specified,
|
|
* restricting eviction to the spa and type given. This function
|
|
* prevents us from trying to evict more from a state's list than
|
|
* is "evictable", and to skip evicting altogether when passed a
|
|
* negative value for "bytes". In contrast, arc_evict_state() will
|
|
* evict everything it can, when passed a negative value for "bytes".
|
|
*/
|
|
static uint64_t
|
|
arc_evict_impl(arc_state_t *state, uint64_t spa, int64_t bytes,
|
|
arc_buf_contents_t type)
|
|
{
|
|
int64_t delta;
|
|
|
|
if (bytes > 0 && zfs_refcount_count(&state->arcs_esize[type]) > 0) {
|
|
delta = MIN(zfs_refcount_count(&state->arcs_esize[type]),
|
|
bytes);
|
|
return (arc_evict_state(state, spa, delta, type));
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* The goal of this function is to evict enough meta data buffers from the
|
|
* ARC in order to enforce the arc_meta_limit. Achieving this is slightly
|
|
* more complicated than it appears because it is common for data buffers
|
|
* to have holds on meta data buffers. In addition, dnode meta data buffers
|
|
* will be held by the dnodes in the block preventing them from being freed.
|
|
* This means we can't simply traverse the ARC and expect to always find
|
|
* enough unheld meta data buffer to release.
|
|
*
|
|
* Therefore, this function has been updated to make alternating passes
|
|
* over the ARC releasing data buffers and then newly unheld meta data
|
|
* buffers. This ensures forward progress is maintained and meta_used
|
|
* will decrease. Normally this is sufficient, but if required the ARC
|
|
* will call the registered prune callbacks causing dentry and inodes to
|
|
* be dropped from the VFS cache. This will make dnode meta data buffers
|
|
* available for reclaim.
|
|
*/
|
|
static uint64_t
|
|
arc_evict_meta_balanced(uint64_t meta_used)
|
|
{
|
|
int64_t delta, prune = 0, adjustmnt;
|
|
uint64_t total_evicted = 0;
|
|
arc_buf_contents_t type = ARC_BUFC_DATA;
|
|
int restarts = MAX(zfs_arc_meta_adjust_restarts, 0);
|
|
|
|
restart:
|
|
/*
|
|
* This slightly differs than the way we evict from the mru in
|
|
* arc_evict because we don't have a "target" value (i.e. no
|
|
* "meta" arc_p). As a result, I think we can completely
|
|
* cannibalize the metadata in the MRU before we evict the
|
|
* metadata from the MFU. I think we probably need to implement a
|
|
* "metadata arc_p" value to do this properly.
|
|
*/
|
|
adjustmnt = meta_used - arc_meta_limit;
|
|
|
|
if (adjustmnt > 0 &&
|
|
zfs_refcount_count(&arc_mru->arcs_esize[type]) > 0) {
|
|
delta = MIN(zfs_refcount_count(&arc_mru->arcs_esize[type]),
|
|
adjustmnt);
|
|
total_evicted += arc_evict_impl(arc_mru, 0, delta, type);
|
|
adjustmnt -= delta;
|
|
}
|
|
|
|
/*
|
|
* We can't afford to recalculate adjustmnt here. If we do,
|
|
* new metadata buffers can sneak into the MRU or ANON lists,
|
|
* thus penalize the MFU metadata. Although the fudge factor is
|
|
* small, it has been empirically shown to be significant for
|
|
* certain workloads (e.g. creating many empty directories). As
|
|
* such, we use the original calculation for adjustmnt, and
|
|
* simply decrement the amount of data evicted from the MRU.
|
|
*/
|
|
|
|
if (adjustmnt > 0 &&
|
|
zfs_refcount_count(&arc_mfu->arcs_esize[type]) > 0) {
|
|
delta = MIN(zfs_refcount_count(&arc_mfu->arcs_esize[type]),
|
|
adjustmnt);
|
|
total_evicted += arc_evict_impl(arc_mfu, 0, delta, type);
|
|
}
|
|
|
|
adjustmnt = meta_used - arc_meta_limit;
|
|
|
|
if (adjustmnt > 0 &&
|
|
zfs_refcount_count(&arc_mru_ghost->arcs_esize[type]) > 0) {
|
|
delta = MIN(adjustmnt,
|
|
zfs_refcount_count(&arc_mru_ghost->arcs_esize[type]));
|
|
total_evicted += arc_evict_impl(arc_mru_ghost, 0, delta, type);
|
|
adjustmnt -= delta;
|
|
}
|
|
|
|
if (adjustmnt > 0 &&
|
|
zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type]) > 0) {
|
|
delta = MIN(adjustmnt,
|
|
zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type]));
|
|
total_evicted += arc_evict_impl(arc_mfu_ghost, 0, delta, type);
|
|
}
|
|
|
|
/*
|
|
* If after attempting to make the requested adjustment to the ARC
|
|
* the meta limit is still being exceeded then request that the
|
|
* higher layers drop some cached objects which have holds on ARC
|
|
* meta buffers. Requests to the upper layers will be made with
|
|
* increasingly large scan sizes until the ARC is below the limit.
|
|
*/
|
|
if (meta_used > arc_meta_limit) {
|
|
if (type == ARC_BUFC_DATA) {
|
|
type = ARC_BUFC_METADATA;
|
|
} else {
|
|
type = ARC_BUFC_DATA;
|
|
|
|
if (zfs_arc_meta_prune) {
|
|
prune += zfs_arc_meta_prune;
|
|
arc_prune_async(prune);
|
|
}
|
|
}
|
|
|
|
if (restarts > 0) {
|
|
restarts--;
|
|
goto restart;
|
|
}
|
|
}
|
|
return (total_evicted);
|
|
}
|
|
|
|
/*
|
|
* Evict metadata buffers from the cache, such that arc_meta_used is
|
|
* capped by the arc_meta_limit tunable.
|
|
*/
|
|
static uint64_t
|
|
arc_evict_meta_only(uint64_t meta_used)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
int64_t target;
|
|
|
|
/*
|
|
* If we're over the meta limit, we want to evict enough
|
|
* metadata to get back under the meta limit. We don't want to
|
|
* evict so much that we drop the MRU below arc_p, though. If
|
|
* we're over the meta limit more than we're over arc_p, we
|
|
* evict some from the MRU here, and some from the MFU below.
|
|
*/
|
|
target = MIN((int64_t)(meta_used - arc_meta_limit),
|
|
(int64_t)(zfs_refcount_count(&arc_anon->arcs_size) +
|
|
zfs_refcount_count(&arc_mru->arcs_size) - arc_p));
|
|
|
|
total_evicted += arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
|
|
/*
|
|
* Similar to the above, we want to evict enough bytes to get us
|
|
* below the meta limit, but not so much as to drop us below the
|
|
* space allotted to the MFU (which is defined as arc_c - arc_p).
|
|
*/
|
|
target = MIN((int64_t)(meta_used - arc_meta_limit),
|
|
(int64_t)(zfs_refcount_count(&arc_mfu->arcs_size) -
|
|
(arc_c - arc_p)));
|
|
|
|
total_evicted += arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
static uint64_t
|
|
arc_evict_meta(uint64_t meta_used)
|
|
{
|
|
if (zfs_arc_meta_strategy == ARC_STRATEGY_META_ONLY)
|
|
return (arc_evict_meta_only(meta_used));
|
|
else
|
|
return (arc_evict_meta_balanced(meta_used));
|
|
}
|
|
|
|
/*
|
|
* Return the type of the oldest buffer in the given arc state
|
|
*
|
|
* This function will select a random sublist of type ARC_BUFC_DATA and
|
|
* a random sublist of type ARC_BUFC_METADATA. The tail of each sublist
|
|
* is compared, and the type which contains the "older" buffer will be
|
|
* returned.
|
|
*/
|
|
static arc_buf_contents_t
|
|
arc_evict_type(arc_state_t *state)
|
|
{
|
|
multilist_t *data_ml = state->arcs_list[ARC_BUFC_DATA];
|
|
multilist_t *meta_ml = state->arcs_list[ARC_BUFC_METADATA];
|
|
int data_idx = multilist_get_random_index(data_ml);
|
|
int meta_idx = multilist_get_random_index(meta_ml);
|
|
multilist_sublist_t *data_mls;
|
|
multilist_sublist_t *meta_mls;
|
|
arc_buf_contents_t type;
|
|
arc_buf_hdr_t *data_hdr;
|
|
arc_buf_hdr_t *meta_hdr;
|
|
|
|
/*
|
|
* We keep the sublist lock until we're finished, to prevent
|
|
* the headers from being destroyed via arc_evict_state().
|
|
*/
|
|
data_mls = multilist_sublist_lock(data_ml, data_idx);
|
|
meta_mls = multilist_sublist_lock(meta_ml, meta_idx);
|
|
|
|
/*
|
|
* These two loops are to ensure we skip any markers that
|
|
* might be at the tail of the lists due to arc_evict_state().
|
|
*/
|
|
|
|
for (data_hdr = multilist_sublist_tail(data_mls); data_hdr != NULL;
|
|
data_hdr = multilist_sublist_prev(data_mls, data_hdr)) {
|
|
if (data_hdr->b_spa != 0)
|
|
break;
|
|
}
|
|
|
|
for (meta_hdr = multilist_sublist_tail(meta_mls); meta_hdr != NULL;
|
|
meta_hdr = multilist_sublist_prev(meta_mls, meta_hdr)) {
|
|
if (meta_hdr->b_spa != 0)
|
|
break;
|
|
}
|
|
|
|
if (data_hdr == NULL && meta_hdr == NULL) {
|
|
type = ARC_BUFC_DATA;
|
|
} else if (data_hdr == NULL) {
|
|
ASSERT3P(meta_hdr, !=, NULL);
|
|
type = ARC_BUFC_METADATA;
|
|
} else if (meta_hdr == NULL) {
|
|
ASSERT3P(data_hdr, !=, NULL);
|
|
type = ARC_BUFC_DATA;
|
|
} else {
|
|
ASSERT3P(data_hdr, !=, NULL);
|
|
ASSERT3P(meta_hdr, !=, NULL);
|
|
|
|
/* The headers can't be on the sublist without an L1 header */
|
|
ASSERT(HDR_HAS_L1HDR(data_hdr));
|
|
ASSERT(HDR_HAS_L1HDR(meta_hdr));
|
|
|
|
if (data_hdr->b_l1hdr.b_arc_access <
|
|
meta_hdr->b_l1hdr.b_arc_access) {
|
|
type = ARC_BUFC_DATA;
|
|
} else {
|
|
type = ARC_BUFC_METADATA;
|
|
}
|
|
}
|
|
|
|
multilist_sublist_unlock(meta_mls);
|
|
multilist_sublist_unlock(data_mls);
|
|
|
|
return (type);
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the cache, such that arc_size is capped by arc_c.
|
|
*/
|
|
static uint64_t
|
|
arc_evict(void)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
uint64_t bytes;
|
|
int64_t target;
|
|
uint64_t asize = aggsum_value(&arc_size);
|
|
uint64_t ameta = aggsum_value(&arc_meta_used);
|
|
|
|
/*
|
|
* If we're over arc_meta_limit, we want to correct that before
|
|
* potentially evicting data buffers below.
|
|
*/
|
|
total_evicted += arc_evict_meta(ameta);
|
|
|
|
/*
|
|
* Adjust MRU size
|
|
*
|
|
* If we're over the target cache size, we want to evict enough
|
|
* from the list to get back to our target size. We don't want
|
|
* to evict too much from the MRU, such that it drops below
|
|
* arc_p. So, if we're over our target cache size more than
|
|
* the MRU is over arc_p, we'll evict enough to get back to
|
|
* arc_p here, and then evict more from the MFU below.
|
|
*/
|
|
target = MIN((int64_t)(asize - arc_c),
|
|
(int64_t)(zfs_refcount_count(&arc_anon->arcs_size) +
|
|
zfs_refcount_count(&arc_mru->arcs_size) + ameta - arc_p));
|
|
|
|
/*
|
|
* If we're below arc_meta_min, always prefer to evict data.
|
|
* Otherwise, try to satisfy the requested number of bytes to
|
|
* evict from the type which contains older buffers; in an
|
|
* effort to keep newer buffers in the cache regardless of their
|
|
* type. If we cannot satisfy the number of bytes from this
|
|
* type, spill over into the next type.
|
|
*/
|
|
if (arc_evict_type(arc_mru) == ARC_BUFC_METADATA &&
|
|
ameta > arc_meta_min) {
|
|
bytes = arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* metadata, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mru, 0, target, ARC_BUFC_DATA);
|
|
} else {
|
|
bytes = arc_evict_impl(arc_mru, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* data, we try to get the rest from metadata.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
}
|
|
|
|
/*
|
|
* Re-sum ARC stats after the first round of evictions.
|
|
*/
|
|
asize = aggsum_value(&arc_size);
|
|
ameta = aggsum_value(&arc_meta_used);
|
|
|
|
|
|
/*
|
|
* Adjust MFU size
|
|
*
|
|
* Now that we've tried to evict enough from the MRU to get its
|
|
* size back to arc_p, if we're still above the target cache
|
|
* size, we evict the rest from the MFU.
|
|
*/
|
|
target = asize - arc_c;
|
|
|
|
if (arc_evict_type(arc_mfu) == ARC_BUFC_METADATA &&
|
|
ameta > arc_meta_min) {
|
|
bytes = arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* metadata, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_DATA);
|
|
} else {
|
|
bytes = arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* data, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
}
|
|
|
|
/*
|
|
* Adjust ghost lists
|
|
*
|
|
* In addition to the above, the ARC also defines target values
|
|
* for the ghost lists. The sum of the mru list and mru ghost
|
|
* list should never exceed the target size of the cache, and
|
|
* the sum of the mru list, mfu list, mru ghost list, and mfu
|
|
* ghost list should never exceed twice the target size of the
|
|
* cache. The following logic enforces these limits on the ghost
|
|
* caches, and evicts from them as needed.
|
|
*/
|
|
target = zfs_refcount_count(&arc_mru->arcs_size) +
|
|
zfs_refcount_count(&arc_mru_ghost->arcs_size) - arc_c;
|
|
|
|
bytes = arc_evict_impl(arc_mru_ghost, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mru_ghost, 0, target, ARC_BUFC_METADATA);
|
|
|
|
/*
|
|
* We assume the sum of the mru list and mfu list is less than
|
|
* or equal to arc_c (we enforced this above), which means we
|
|
* can use the simpler of the two equations below:
|
|
*
|
|
* mru + mfu + mru ghost + mfu ghost <= 2 * arc_c
|
|
* mru ghost + mfu ghost <= arc_c
|
|
*/
|
|
target = zfs_refcount_count(&arc_mru_ghost->arcs_size) +
|
|
zfs_refcount_count(&arc_mfu_ghost->arcs_size) - arc_c;
|
|
|
|
bytes = arc_evict_impl(arc_mfu_ghost, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_evict_impl(arc_mfu_ghost, 0, target, ARC_BUFC_METADATA);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
void
|
|
arc_flush(spa_t *spa, boolean_t retry)
|
|
{
|
|
uint64_t guid = 0;
|
|
|
|
/*
|
|
* If retry is B_TRUE, a spa must not be specified since we have
|
|
* no good way to determine if all of a spa's buffers have been
|
|
* evicted from an arc state.
|
|
*/
|
|
ASSERT(!retry || spa == 0);
|
|
|
|
if (spa != NULL)
|
|
guid = spa_load_guid(spa);
|
|
|
|
(void) arc_flush_state(arc_mru, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mru, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mfu, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mfu, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry);
|
|
}
|
|
|
|
void
|
|
arc_reduce_target_size(int64_t to_free)
|
|
{
|
|
uint64_t asize = aggsum_value(&arc_size);
|
|
|
|
/*
|
|
* All callers want the ARC to actually evict (at least) this much
|
|
* memory. Therefore we reduce from the lower of the current size and
|
|
* the target size. This way, even if arc_c is much higher than
|
|
* arc_size (as can be the case after many calls to arc_freed(), we will
|
|
* immediately have arc_c < arc_size and therefore the arc_evict_zthr
|
|
* will evict.
|
|
*/
|
|
uint64_t c = MIN(arc_c, asize);
|
|
|
|
if (c > to_free && c - to_free > arc_c_min) {
|
|
arc_c = c - to_free;
|
|
atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift));
|
|
if (arc_p > arc_c)
|
|
arc_p = (arc_c >> 1);
|
|
ASSERT(arc_c >= arc_c_min);
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
} else {
|
|
arc_c = arc_c_min;
|
|
}
|
|
|
|
if (asize > arc_c) {
|
|
/* See comment in arc_evict_cb_check() on why lock+flag */
|
|
mutex_enter(&arc_evict_lock);
|
|
arc_evict_needed = B_TRUE;
|
|
mutex_exit(&arc_evict_lock);
|
|
zthr_wakeup(arc_evict_zthr);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Determine if the system is under memory pressure and is asking
|
|
* to reclaim memory. A return value of B_TRUE indicates that the system
|
|
* is under memory pressure and that the arc should adjust accordingly.
|
|
*/
|
|
boolean_t
|
|
arc_reclaim_needed(void)
|
|
{
|
|
return (arc_available_memory() < 0);
|
|
}
|
|
|
|
void
|
|
arc_kmem_reap_soon(void)
|
|
{
|
|
size_t i;
|
|
kmem_cache_t *prev_cache = NULL;
|
|
kmem_cache_t *prev_data_cache = NULL;
|
|
extern kmem_cache_t *zio_buf_cache[];
|
|
extern kmem_cache_t *zio_data_buf_cache[];
|
|
|
|
#ifdef _KERNEL
|
|
if ((aggsum_compare(&arc_meta_used, arc_meta_limit) >= 0) &&
|
|
zfs_arc_meta_prune) {
|
|
/*
|
|
* We are exceeding our meta-data cache limit.
|
|
* Prune some entries to release holds on meta-data.
|
|
*/
|
|
arc_prune_async(zfs_arc_meta_prune);
|
|
}
|
|
#if defined(_ILP32)
|
|
/*
|
|
* Reclaim unused memory from all kmem caches.
|
|
*/
|
|
kmem_reap();
|
|
#endif
|
|
#endif
|
|
|
|
for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) {
|
|
#if defined(_ILP32)
|
|
/* reach upper limit of cache size on 32-bit */
|
|
if (zio_buf_cache[i] == NULL)
|
|
break;
|
|
#endif
|
|
if (zio_buf_cache[i] != prev_cache) {
|
|
prev_cache = zio_buf_cache[i];
|
|
kmem_cache_reap_now(zio_buf_cache[i]);
|
|
}
|
|
if (zio_data_buf_cache[i] != prev_data_cache) {
|
|
prev_data_cache = zio_data_buf_cache[i];
|
|
kmem_cache_reap_now(zio_data_buf_cache[i]);
|
|
}
|
|
}
|
|
kmem_cache_reap_now(buf_cache);
|
|
kmem_cache_reap_now(hdr_full_cache);
|
|
kmem_cache_reap_now(hdr_l2only_cache);
|
|
kmem_cache_reap_now(zfs_btree_leaf_cache);
|
|
abd_cache_reap_now();
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static boolean_t
|
|
arc_evict_cb_check(void *arg, zthr_t *zthr)
|
|
{
|
|
/*
|
|
* This is necessary so that any changes which may have been made to
|
|
* many of the zfs_arc_* module parameters will be propagated to
|
|
* their actual internal variable counterparts. Without this,
|
|
* changing those module params at runtime would have no effect.
|
|
*/
|
|
arc_tuning_update(B_FALSE);
|
|
|
|
/*
|
|
* This is necessary in order to keep the kstat information
|
|
* up to date for tools that display kstat data such as the
|
|
* mdb ::arc dcmd and the Linux crash utility. These tools
|
|
* typically do not call kstat's update function, but simply
|
|
* dump out stats from the most recent update. Without
|
|
* this call, these commands may show stale stats for the
|
|
* anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even
|
|
* with this change, the data might be up to 1 second
|
|
* out of date(the arc_evict_zthr has a maximum sleep
|
|
* time of 1 second); but that should suffice. The
|
|
* arc_state_t structures can be queried directly if more
|
|
* accurate information is needed.
|
|
*/
|
|
if (arc_ksp != NULL)
|
|
arc_ksp->ks_update(arc_ksp, KSTAT_READ);
|
|
|
|
/*
|
|
* We have to rely on arc_wait_for_eviction() to tell us when to
|
|
* evict, rather than checking if we are overflowing here, so that we
|
|
* are sure to not leave arc_wait_for_eviction() waiting on aew_cv.
|
|
* If we have become "not overflowing" since arc_wait_for_eviction()
|
|
* checked, we need to wake it up. We could broadcast the CV here,
|
|
* but arc_wait_for_eviction() may have not yet gone to sleep. We
|
|
* would need to use a mutex to ensure that this function doesn't
|
|
* broadcast until arc_wait_for_eviction() has gone to sleep (e.g.
|
|
* the arc_evict_lock). However, the lock ordering of such a lock
|
|
* would necessarily be incorrect with respect to the zthr_lock,
|
|
* which is held before this function is called, and is held by
|
|
* arc_wait_for_eviction() when it calls zthr_wakeup().
|
|
*/
|
|
return (arc_evict_needed);
|
|
}
|
|
|
|
/*
|
|
* Keep arc_size under arc_c by running arc_evict which evicts data
|
|
* from the ARC.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_evict_cb(void *arg, zthr_t *zthr)
|
|
{
|
|
uint64_t evicted = 0;
|
|
fstrans_cookie_t cookie = spl_fstrans_mark();
|
|
|
|
/* Evict from cache */
|
|
evicted = arc_evict();
|
|
|
|
/*
|
|
* If evicted is zero, we couldn't evict anything
|
|
* via arc_evict(). This could be due to hash lock
|
|
* collisions, but more likely due to the majority of
|
|
* arc buffers being unevictable. Therefore, even if
|
|
* arc_size is above arc_c, another pass is unlikely to
|
|
* be helpful and could potentially cause us to enter an
|
|
* infinite loop. Additionally, zthr_iscancelled() is
|
|
* checked here so that if the arc is shutting down, the
|
|
* broadcast will wake any remaining arc evict waiters.
|
|
*/
|
|
mutex_enter(&arc_evict_lock);
|
|
arc_evict_needed = !zthr_iscancelled(arc_evict_zthr) &&
|
|
evicted > 0 && aggsum_compare(&arc_size, arc_c) > 0;
|
|
if (!arc_evict_needed) {
|
|
/*
|
|
* We're either no longer overflowing, or we
|
|
* can't evict anything more, so we should wake
|
|
* arc_get_data_impl() sooner.
|
|
*/
|
|
arc_evict_waiter_t *aw;
|
|
while ((aw = list_remove_head(&arc_evict_waiters)) != NULL) {
|
|
cv_broadcast(&aw->aew_cv);
|
|
}
|
|
arc_set_need_free();
|
|
}
|
|
mutex_exit(&arc_evict_lock);
|
|
spl_fstrans_unmark(cookie);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static boolean_t
|
|
arc_reap_cb_check(void *arg, zthr_t *zthr)
|
|
{
|
|
int64_t free_memory = arc_available_memory();
|
|
|
|
/*
|
|
* If a kmem reap is already active, don't schedule more. We must
|
|
* check for this because kmem_cache_reap_soon() won't actually
|
|
* block on the cache being reaped (this is to prevent callers from
|
|
* becoming implicitly blocked by a system-wide kmem reap -- which,
|
|
* on a system with many, many full magazines, can take minutes).
|
|
*/
|
|
if (!kmem_cache_reap_active() && free_memory < 0) {
|
|
|
|
arc_no_grow = B_TRUE;
|
|
arc_warm = B_TRUE;
|
|
/*
|
|
* Wait at least zfs_grow_retry (default 5) seconds
|
|
* before considering growing.
|
|
*/
|
|
arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry);
|
|
return (B_TRUE);
|
|
} else if (free_memory < arc_c >> arc_no_grow_shift) {
|
|
arc_no_grow = B_TRUE;
|
|
} else if (gethrtime() >= arc_growtime) {
|
|
arc_no_grow = B_FALSE;
|
|
}
|
|
|
|
return (B_FALSE);
|
|
}
|
|
|
|
/*
|
|
* Keep enough free memory in the system by reaping the ARC's kmem
|
|
* caches. To cause more slabs to be reapable, we may reduce the
|
|
* target size of the cache (arc_c), causing the arc_evict_cb()
|
|
* to free more buffers.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_reap_cb(void *arg, zthr_t *zthr)
|
|
{
|
|
int64_t free_memory;
|
|
fstrans_cookie_t cookie = spl_fstrans_mark();
|
|
|
|
/*
|
|
* Kick off asynchronous kmem_reap()'s of all our caches.
|
|
*/
|
|
arc_kmem_reap_soon();
|
|
|
|
/*
|
|
* Wait at least arc_kmem_cache_reap_retry_ms between
|
|
* arc_kmem_reap_soon() calls. Without this check it is possible to
|
|
* end up in a situation where we spend lots of time reaping
|
|
* caches, while we're near arc_c_min. Waiting here also gives the
|
|
* subsequent free memory check a chance of finding that the
|
|
* asynchronous reap has already freed enough memory, and we don't
|
|
* need to call arc_reduce_target_size().
|
|
*/
|
|
delay((hz * arc_kmem_cache_reap_retry_ms + 999) / 1000);
|
|
|
|
/*
|
|
* Reduce the target size as needed to maintain the amount of free
|
|
* memory in the system at a fraction of the arc_size (1/128th by
|
|
* default). If oversubscribed (free_memory < 0) then reduce the
|
|
* target arc_size by the deficit amount plus the fractional
|
|
* amount. If free memory is positive but less then the fractional
|
|
* amount, reduce by what is needed to hit the fractional amount.
|
|
*/
|
|
free_memory = arc_available_memory();
|
|
|
|
int64_t to_free =
|
|
(arc_c >> arc_shrink_shift) - free_memory;
|
|
if (to_free > 0) {
|
|
arc_reduce_target_size(to_free);
|
|
}
|
|
spl_fstrans_unmark(cookie);
|
|
}
|
|
|
|
#ifdef _KERNEL
|
|
/*
|
|
* Determine the amount of memory eligible for eviction contained in the
|
|
* ARC. All clean data reported by the ghost lists can always be safely
|
|
* evicted. Due to arc_c_min, the same does not hold for all clean data
|
|
* contained by the regular mru and mfu lists.
|
|
*
|
|
* In the case of the regular mru and mfu lists, we need to report as
|
|
* much clean data as possible, such that evicting that same reported
|
|
* data will not bring arc_size below arc_c_min. Thus, in certain
|
|
* circumstances, the total amount of clean data in the mru and mfu
|
|
* lists might not actually be evictable.
|
|
*
|
|
* The following two distinct cases are accounted for:
|
|
*
|
|
* 1. The sum of the amount of dirty data contained by both the mru and
|
|
* mfu lists, plus the ARC's other accounting (e.g. the anon list),
|
|
* is greater than or equal to arc_c_min.
|
|
* (i.e. amount of dirty data >= arc_c_min)
|
|
*
|
|
* This is the easy case; all clean data contained by the mru and mfu
|
|
* lists is evictable. Evicting all clean data can only drop arc_size
|
|
* to the amount of dirty data, which is greater than arc_c_min.
|
|
*
|
|
* 2. The sum of the amount of dirty data contained by both the mru and
|
|
* mfu lists, plus the ARC's other accounting (e.g. the anon list),
|
|
* is less than arc_c_min.
|
|
* (i.e. arc_c_min > amount of dirty data)
|
|
*
|
|
* 2.1. arc_size is greater than or equal arc_c_min.
|
|
* (i.e. arc_size >= arc_c_min > amount of dirty data)
|
|
*
|
|
* In this case, not all clean data from the regular mru and mfu
|
|
* lists is actually evictable; we must leave enough clean data
|
|
* to keep arc_size above arc_c_min. Thus, the maximum amount of
|
|
* evictable data from the two lists combined, is exactly the
|
|
* difference between arc_size and arc_c_min.
|
|
*
|
|
* 2.2. arc_size is less than arc_c_min
|
|
* (i.e. arc_c_min > arc_size > amount of dirty data)
|
|
*
|
|
* In this case, none of the data contained in the mru and mfu
|
|
* lists is evictable, even if it's clean. Since arc_size is
|
|
* already below arc_c_min, evicting any more would only
|
|
* increase this negative difference.
|
|
*/
|
|
|
|
#endif /* _KERNEL */
|
|
|
|
/*
|
|
* Adapt arc info given the number of bytes we are trying to add and
|
|
* the state that we are coming from. This function is only called
|
|
* when we are adding new content to the cache.
|
|
*/
|
|
static void
|
|
arc_adapt(int bytes, arc_state_t *state)
|
|
{
|
|
int mult;
|
|
uint64_t arc_p_min = (arc_c >> arc_p_min_shift);
|
|
int64_t mrug_size = zfs_refcount_count(&arc_mru_ghost->arcs_size);
|
|
int64_t mfug_size = zfs_refcount_count(&arc_mfu_ghost->arcs_size);
|
|
|
|
ASSERT(bytes > 0);
|
|
/*
|
|
* Adapt the target size of the MRU list:
|
|
* - if we just hit in the MRU ghost list, then increase
|
|
* the target size of the MRU list.
|
|
* - if we just hit in the MFU ghost list, then increase
|
|
* the target size of the MFU list by decreasing the
|
|
* target size of the MRU list.
|
|
*/
|
|
if (state == arc_mru_ghost) {
|
|
mult = (mrug_size >= mfug_size) ? 1 : (mfug_size / mrug_size);
|
|
if (!zfs_arc_p_dampener_disable)
|
|
mult = MIN(mult, 10); /* avoid wild arc_p adjustment */
|
|
|
|
arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult);
|
|
} else if (state == arc_mfu_ghost) {
|
|
uint64_t delta;
|
|
|
|
mult = (mfug_size >= mrug_size) ? 1 : (mrug_size / mfug_size);
|
|
if (!zfs_arc_p_dampener_disable)
|
|
mult = MIN(mult, 10);
|
|
|
|
delta = MIN(bytes * mult, arc_p);
|
|
arc_p = MAX(arc_p_min, arc_p - delta);
|
|
}
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
|
|
/*
|
|
* Wake reap thread if we do not have any available memory
|
|
*/
|
|
if (arc_reclaim_needed()) {
|
|
zthr_wakeup(arc_reap_zthr);
|
|
return;
|
|
}
|
|
|
|
if (arc_no_grow)
|
|
return;
|
|
|
|
if (arc_c >= arc_c_max)
|
|
return;
|
|
|
|
/*
|
|
* If we're within (2 * maxblocksize) bytes of the target
|
|
* cache size, increment the target cache size
|
|
*/
|
|
ASSERT3U(arc_c, >=, 2ULL << SPA_MAXBLOCKSHIFT);
|
|
if (aggsum_upper_bound(&arc_size) >=
|
|
arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) {
|
|
atomic_add_64(&arc_c, (int64_t)bytes);
|
|
if (arc_c > arc_c_max)
|
|
arc_c = arc_c_max;
|
|
else if (state == arc_anon)
|
|
atomic_add_64(&arc_p, (int64_t)bytes);
|
|
if (arc_p > arc_c)
|
|
arc_p = arc_c;
|
|
}
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
}
|
|
|
|
/*
|
|
* Check if arc_size has grown past our upper threshold, determined by
|
|
* zfs_arc_overflow_shift.
|
|
*/
|
|
boolean_t
|
|
arc_is_overflowing(void)
|
|
{
|
|
/* Always allow at least one block of overflow */
|
|
int64_t overflow = MAX(SPA_MAXBLOCKSIZE,
|
|
arc_c >> zfs_arc_overflow_shift);
|
|
|
|
/*
|
|
* We just compare the lower bound here for performance reasons. Our
|
|
* primary goals are to make sure that the arc never grows without
|
|
* bound, and that it can reach its maximum size. This check
|
|
* accomplishes both goals. The maximum amount we could run over by is
|
|
* 2 * aggsum_borrow_multiplier * NUM_CPUS * the average size of a block
|
|
* in the ARC. In practice, that's in the tens of MB, which is low
|
|
* enough to be safe.
|
|
*/
|
|
return (aggsum_lower_bound(&arc_size) >= (int64_t)arc_c + overflow);
|
|
}
|
|
|
|
static abd_t *
|
|
arc_get_data_abd(arc_buf_hdr_t *hdr, uint64_t size, void *tag,
|
|
boolean_t do_adapt)
|
|
{
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
arc_get_data_impl(hdr, size, tag, do_adapt);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
return (abd_alloc(size, B_TRUE));
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
return (abd_alloc(size, B_FALSE));
|
|
}
|
|
}
|
|
|
|
static void *
|
|
arc_get_data_buf(arc_buf_hdr_t *hdr, uint64_t size, void *tag)
|
|
{
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
arc_get_data_impl(hdr, size, tag, B_TRUE);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
return (zio_buf_alloc(size));
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
return (zio_data_buf_alloc(size));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wait for the specified amount of data (in bytes) to be evicted from the
|
|
* ARC, and for there to be sufficient free memory in the system. Waiting for
|
|
* eviction ensures that the memory used by the ARC decreases. Waiting for
|
|
* free memory ensures that the system won't run out of free pages, regardless
|
|
* of ARC behavior and settings. See arc_lowmem_init().
|
|
*/
|
|
void
|
|
arc_wait_for_eviction(uint64_t amount)
|
|
{
|
|
mutex_enter(&arc_evict_lock);
|
|
if (arc_is_overflowing()) {
|
|
arc_evict_needed = B_TRUE;
|
|
zthr_wakeup(arc_evict_zthr);
|
|
|
|
if (amount != 0) {
|
|
arc_evict_waiter_t aw;
|
|
list_link_init(&aw.aew_node);
|
|
cv_init(&aw.aew_cv, NULL, CV_DEFAULT, NULL);
|
|
|
|
arc_evict_waiter_t *last =
|
|
list_tail(&arc_evict_waiters);
|
|
if (last != NULL) {
|
|
ASSERT3U(last->aew_count, >, arc_evict_count);
|
|
aw.aew_count = last->aew_count + amount;
|
|
} else {
|
|
aw.aew_count = arc_evict_count + amount;
|
|
}
|
|
|
|
list_insert_tail(&arc_evict_waiters, &aw);
|
|
|
|
arc_set_need_free();
|
|
|
|
DTRACE_PROBE3(arc__wait__for__eviction,
|
|
uint64_t, amount,
|
|
uint64_t, arc_evict_count,
|
|
uint64_t, aw.aew_count);
|
|
|
|
/*
|
|
* We will be woken up either when arc_evict_count
|
|
* reaches aew_count, or when the ARC is no longer
|
|
* overflowing and eviction completes.
|
|
*/
|
|
cv_wait(&aw.aew_cv, &arc_evict_lock);
|
|
|
|
/*
|
|
* In case of "false" wakeup, we will still be on the
|
|
* list.
|
|
*/
|
|
if (list_link_active(&aw.aew_node))
|
|
list_remove(&arc_evict_waiters, &aw);
|
|
|
|
cv_destroy(&aw.aew_cv);
|
|
}
|
|
}
|
|
mutex_exit(&arc_evict_lock);
|
|
}
|
|
|
|
/*
|
|
* Allocate a block and return it to the caller. If we are hitting the
|
|
* hard limit for the cache size, we must sleep, waiting for the eviction
|
|
* thread to catch up. If we're past the target size but below the hard
|
|
* limit, we'll only signal the reclaim thread and continue on.
|
|
*/
|
|
static void
|
|
arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag,
|
|
boolean_t do_adapt)
|
|
{
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
if (do_adapt)
|
|
arc_adapt(size, state);
|
|
|
|
/*
|
|
* If arc_size is currently overflowing, we must be adding data
|
|
* faster than we are evicting. To ensure we don't compound the
|
|
* problem by adding more data and forcing arc_size to grow even
|
|
* further past it's target size, we wait for the eviction thread to
|
|
* make some progress. We also wait for there to be sufficient free
|
|
* memory in the system, as measured by arc_free_memory().
|
|
*
|
|
* Specifically, we wait for zfs_arc_eviction_pct percent of the
|
|
* requested size to be evicted. This should be more than 100%, to
|
|
* ensure that that progress is also made towards getting arc_size
|
|
* under arc_c. See the comment above zfs_arc_eviction_pct.
|
|
*
|
|
* We do the overflowing check without holding the arc_evict_lock to
|
|
* reduce lock contention in this hot path. Note that
|
|
* arc_wait_for_eviction() will acquire the lock and check again to
|
|
* ensure we are truly overflowing before blocking.
|
|
*/
|
|
if (arc_is_overflowing()) {
|
|
arc_wait_for_eviction(size *
|
|
zfs_arc_eviction_pct / 100);
|
|
}
|
|
|
|
VERIFY3U(hdr->b_type, ==, type);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
arc_space_consume(size, ARC_SPACE_META);
|
|
} else {
|
|
arc_space_consume(size, ARC_SPACE_DATA);
|
|
}
|
|
|
|
/*
|
|
* Update the state size. Note that ghost states have a
|
|
* "ghost size" and so don't need to be updated.
|
|
*/
|
|
if (!GHOST_STATE(state)) {
|
|
|
|
(void) zfs_refcount_add_many(&state->arcs_size, size, tag);
|
|
|
|
/*
|
|
* If this is reached via arc_read, the link is
|
|
* protected by the hash lock. If reached via
|
|
* arc_buf_alloc, the header should not be accessed by
|
|
* any other thread. And, if reached via arc_read_done,
|
|
* the hash lock will protect it if it's found in the
|
|
* hash table; otherwise no other thread should be
|
|
* trying to [add|remove]_reference it.
|
|
*/
|
|
if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) {
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
(void) zfs_refcount_add_many(&state->arcs_esize[type],
|
|
size, tag);
|
|
}
|
|
|
|
/*
|
|
* If we are growing the cache, and we are adding anonymous
|
|
* data, and we have outgrown arc_p, update arc_p
|
|
*/
|
|
if (aggsum_upper_bound(&arc_size) < arc_c &&
|
|
hdr->b_l1hdr.b_state == arc_anon &&
|
|
(zfs_refcount_count(&arc_anon->arcs_size) +
|
|
zfs_refcount_count(&arc_mru->arcs_size) > arc_p))
|
|
arc_p = MIN(arc_c, arc_p + size);
|
|
}
|
|
}
|
|
|
|
static void
|
|
arc_free_data_abd(arc_buf_hdr_t *hdr, abd_t *abd, uint64_t size, void *tag)
|
|
{
|
|
arc_free_data_impl(hdr, size, tag);
|
|
abd_free(abd);
|
|
}
|
|
|
|
static void
|
|
arc_free_data_buf(arc_buf_hdr_t *hdr, void *buf, uint64_t size, void *tag)
|
|
{
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
arc_free_data_impl(hdr, size, tag);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
zio_buf_free(buf, size);
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
zio_data_buf_free(buf, size);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Free the arc data buffer.
|
|
*/
|
|
static void
|
|
arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag)
|
|
{
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
/* protected by hash lock, if in the hash table */
|
|
if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) {
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT(state != arc_anon && state != arc_l2c_only);
|
|
|
|
(void) zfs_refcount_remove_many(&state->arcs_esize[type],
|
|
size, tag);
|
|
}
|
|
(void) zfs_refcount_remove_many(&state->arcs_size, size, tag);
|
|
|
|
VERIFY3U(hdr->b_type, ==, type);
|
|
if (type == ARC_BUFC_METADATA) {
|
|
arc_space_return(size, ARC_SPACE_META);
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
arc_space_return(size, ARC_SPACE_DATA);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This routine is called whenever a buffer is accessed.
|
|
* NOTE: the hash lock is dropped in this function.
|
|
*/
|
|
static void
|
|
arc_access(arc_buf_hdr_t *hdr, kmutex_t *hash_lock)
|
|
{
|
|
clock_t now;
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
/*
|
|
* This buffer is not in the cache, and does not
|
|
* appear in our "ghost" list. Add the new buffer
|
|
* to the MRU state.
|
|
*/
|
|
|
|
ASSERT0(hdr->b_l1hdr.b_arc_access);
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mru, hdr, hash_lock);
|
|
|
|
} else if (hdr->b_l1hdr.b_state == arc_mru) {
|
|
now = ddi_get_lbolt();
|
|
|
|
/*
|
|
* If this buffer is here because of a prefetch, then either:
|
|
* - clear the flag if this is a "referencing" read
|
|
* (any subsequent access will bump this into the MFU state).
|
|
* or
|
|
* - move the buffer to the head of the list if this is
|
|
* another prefetch (to make it less likely to be evicted).
|
|
*/
|
|
if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) {
|
|
if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) {
|
|
/* link protected by hash lock */
|
|
ASSERT(multilist_link_active(
|
|
&hdr->b_l1hdr.b_arc_node));
|
|
} else {
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_PREFETCH |
|
|
ARC_FLAG_PRESCIENT_PREFETCH);
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_hits);
|
|
}
|
|
hdr->b_l1hdr.b_arc_access = now;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* This buffer has been "accessed" only once so far,
|
|
* but it is still in the cache. Move it to the MFU
|
|
* state.
|
|
*/
|
|
if (ddi_time_after(now, hdr->b_l1hdr.b_arc_access +
|
|
ARC_MINTIME)) {
|
|
/*
|
|
* More than 125ms have passed since we
|
|
* instantiated this buffer. Move it to the
|
|
* most frequently used state.
|
|
*/
|
|
hdr->b_l1hdr.b_arc_access = now;
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mfu, hdr, hash_lock);
|
|
}
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_mru_ghost) {
|
|
arc_state_t *new_state;
|
|
/*
|
|
* This buffer has been "accessed" recently, but
|
|
* was evicted from the cache. Move it to the
|
|
* MFU state.
|
|
*/
|
|
|
|
if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) {
|
|
new_state = arc_mru;
|
|
if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) > 0) {
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_PREFETCH |
|
|
ARC_FLAG_PRESCIENT_PREFETCH);
|
|
}
|
|
DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr);
|
|
} else {
|
|
new_state = arc_mfu;
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
}
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
arc_change_state(new_state, hdr, hash_lock);
|
|
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_ghost_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_ghost_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_mfu) {
|
|
/*
|
|
* This buffer has been accessed more than once and is
|
|
* still in the cache. Keep it in the MFU state.
|
|
*
|
|
* NOTE: an add_reference() that occurred when we did
|
|
* the arc_read() will have kicked this off the list.
|
|
* If it was a prefetch, we will explicitly move it to
|
|
* the head of the list now.
|
|
*/
|
|
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mfu_hits);
|
|
ARCSTAT_BUMP(arcstat_mfu_hits);
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
} else if (hdr->b_l1hdr.b_state == arc_mfu_ghost) {
|
|
arc_state_t *new_state = arc_mfu;
|
|
/*
|
|
* This buffer has been accessed more than once but has
|
|
* been evicted from the cache. Move it back to the
|
|
* MFU state.
|
|
*/
|
|
|
|
if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) {
|
|
/*
|
|
* This is a prefetch access...
|
|
* move this block back to the MRU state.
|
|
*/
|
|
new_state = arc_mru;
|
|
}
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(new_state, hdr, hash_lock);
|
|
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mfu_ghost_hits);
|
|
ARCSTAT_BUMP(arcstat_mfu_ghost_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_l2c_only) {
|
|
/*
|
|
* This buffer is on the 2nd Level ARC.
|
|
*/
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mfu, hdr, hash_lock);
|
|
} else {
|
|
cmn_err(CE_PANIC, "invalid arc state 0x%p",
|
|
hdr->b_l1hdr.b_state);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This routine is called by dbuf_hold() to update the arc_access() state
|
|
* which otherwise would be skipped for entries in the dbuf cache.
|
|
*/
|
|
void
|
|
arc_buf_access(arc_buf_t *buf)
|
|
{
|
|
mutex_enter(&buf->b_evict_lock);
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
/*
|
|
* Avoid taking the hash_lock when possible as an optimization.
|
|
* The header must be checked again under the hash_lock in order
|
|
* to handle the case where it is concurrently being released.
|
|
*/
|
|
if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return;
|
|
}
|
|
|
|
kmutex_t *hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
|
|
if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) {
|
|
mutex_exit(hash_lock);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
ARCSTAT_BUMP(arcstat_access_skip);
|
|
return;
|
|
}
|
|
|
|
mutex_exit(&buf->b_evict_lock);
|
|
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
|
|
hdr->b_l1hdr.b_state == arc_mfu);
|
|
|
|
DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr);
|
|
arc_access(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
|
|
ARCSTAT_BUMP(arcstat_hits);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr) && !HDR_PRESCIENT_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, metadata, hits);
|
|
}
|
|
|
|
/* a generic arc_read_done_func_t which you can use */
|
|
/* ARGSUSED */
|
|
void
|
|
arc_bcopy_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
|
|
arc_buf_t *buf, void *arg)
|
|
{
|
|
if (buf == NULL)
|
|
return;
|
|
|
|
bcopy(buf->b_data, arg, arc_buf_size(buf));
|
|
arc_buf_destroy(buf, arg);
|
|
}
|
|
|
|
/* a generic arc_read_done_func_t */
|
|
/* ARGSUSED */
|
|
void
|
|
arc_getbuf_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
|
|
arc_buf_t *buf, void *arg)
|
|
{
|
|
arc_buf_t **bufp = arg;
|
|
|
|
if (buf == NULL) {
|
|
ASSERT(zio == NULL || zio->io_error != 0);
|
|
*bufp = NULL;
|
|
} else {
|
|
ASSERT(zio == NULL || zio->io_error == 0);
|
|
*bufp = buf;
|
|
ASSERT(buf->b_data != NULL);
|
|
}
|
|
}
|
|
|
|
static void
|
|
arc_hdr_verify(arc_buf_hdr_t *hdr, blkptr_t *bp)
|
|
{
|
|
if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) {
|
|
ASSERT3U(HDR_GET_PSIZE(hdr), ==, 0);
|
|
ASSERT3U(arc_hdr_get_compress(hdr), ==, ZIO_COMPRESS_OFF);
|
|
} else {
|
|
if (HDR_COMPRESSION_ENABLED(hdr)) {
|
|
ASSERT3U(arc_hdr_get_compress(hdr), ==,
|
|
BP_GET_COMPRESS(bp));
|
|
}
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp));
|
|
ASSERT3U(HDR_GET_PSIZE(hdr), ==, BP_GET_PSIZE(bp));
|
|
ASSERT3U(!!HDR_PROTECTED(hdr), ==, BP_IS_PROTECTED(bp));
|
|
}
|
|
}
|
|
|
|
static void
|
|
arc_read_done(zio_t *zio)
|
|
{
|
|
blkptr_t *bp = zio->io_bp;
|
|
arc_buf_hdr_t *hdr = zio->io_private;
|
|
kmutex_t *hash_lock = NULL;
|
|
arc_callback_t *callback_list;
|
|
arc_callback_t *acb;
|
|
boolean_t freeable = B_FALSE;
|
|
|
|
/*
|
|
* The hdr was inserted into hash-table and removed from lists
|
|
* prior to starting I/O. We should find this header, since
|
|
* it's in the hash table, and it should be legit since it's
|
|
* not possible to evict it during the I/O. The only possible
|
|
* reason for it not to be found is if we were freed during the
|
|
* read.
|
|
*/
|
|
if (HDR_IN_HASH_TABLE(hdr)) {
|
|
arc_buf_hdr_t *found;
|
|
|
|
ASSERT3U(hdr->b_birth, ==, BP_PHYSICAL_BIRTH(zio->io_bp));
|
|
ASSERT3U(hdr->b_dva.dva_word[0], ==,
|
|
BP_IDENTITY(zio->io_bp)->dva_word[0]);
|
|
ASSERT3U(hdr->b_dva.dva_word[1], ==,
|
|
BP_IDENTITY(zio->io_bp)->dva_word[1]);
|
|
|
|
found = buf_hash_find(hdr->b_spa, zio->io_bp, &hash_lock);
|
|
|
|
ASSERT((found == hdr &&
|
|
DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) ||
|
|
(found == hdr && HDR_L2_READING(hdr)));
|
|
ASSERT3P(hash_lock, !=, NULL);
|
|
}
|
|
|
|
if (BP_IS_PROTECTED(bp)) {
|
|
hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp);
|
|
hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset;
|
|
zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt,
|
|
hdr->b_crypt_hdr.b_iv);
|
|
|
|
if (BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG) {
|
|
void *tmpbuf;
|
|
|
|
tmpbuf = abd_borrow_buf_copy(zio->io_abd,
|
|
sizeof (zil_chain_t));
|
|
zio_crypt_decode_mac_zil(tmpbuf,
|
|
hdr->b_crypt_hdr.b_mac);
|
|
abd_return_buf(zio->io_abd, tmpbuf,
|
|
sizeof (zil_chain_t));
|
|
} else {
|
|
zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac);
|
|
}
|
|
}
|
|
|
|
if (zio->io_error == 0) {
|
|
/* byteswap if necessary */
|
|
if (BP_SHOULD_BYTESWAP(zio->io_bp)) {
|
|
if (BP_GET_LEVEL(zio->io_bp) > 0) {
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64;
|
|
} else {
|
|
hdr->b_l1hdr.b_byteswap =
|
|
DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp));
|
|
}
|
|
} else {
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS;
|
|
}
|
|
if (!HDR_L2_READING(hdr)) {
|
|
hdr->b_complevel = zio->io_prop.zp_complevel;
|
|
}
|
|
}
|
|
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_L2_EVICTED);
|
|
if (l2arc_noprefetch && HDR_PREFETCH(hdr))
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_L2CACHE);
|
|
|
|
callback_list = hdr->b_l1hdr.b_acb;
|
|
ASSERT3P(callback_list, !=, NULL);
|
|
|
|
if (hash_lock && zio->io_error == 0 &&
|
|
hdr->b_l1hdr.b_state == arc_anon) {
|
|
/*
|
|
* Only call arc_access on anonymous buffers. This is because
|
|
* if we've issued an I/O for an evicted buffer, we've already
|
|
* called arc_access (to prevent any simultaneous readers from
|
|
* getting confused).
|
|
*/
|
|
arc_access(hdr, hash_lock);
|
|
}
|
|
|
|
/*
|
|
* If a read request has a callback (i.e. acb_done is not NULL), then we
|
|
* make a buf containing the data according to the parameters which were
|
|
* passed in. The implementation of arc_buf_alloc_impl() ensures that we
|
|
* aren't needlessly decompressing the data multiple times.
|
|
*/
|
|
int callback_cnt = 0;
|
|
for (acb = callback_list; acb != NULL; acb = acb->acb_next) {
|
|
if (!acb->acb_done)
|
|
continue;
|
|
|
|
callback_cnt++;
|
|
|
|
if (zio->io_error != 0)
|
|
continue;
|
|
|
|
int error = arc_buf_alloc_impl(hdr, zio->io_spa,
|
|
&acb->acb_zb, acb->acb_private, acb->acb_encrypted,
|
|
acb->acb_compressed, acb->acb_noauth, B_TRUE,
|
|
&acb->acb_buf);
|
|
|
|
/*
|
|
* Assert non-speculative zios didn't fail because an
|
|
* encryption key wasn't loaded
|
|
*/
|
|
ASSERT((zio->io_flags & ZIO_FLAG_SPECULATIVE) ||
|
|
error != EACCES);
|
|
|
|
/*
|
|
* If we failed to decrypt, report an error now (as the zio
|
|
* layer would have done if it had done the transforms).
|
|
*/
|
|
if (error == ECKSUM) {
|
|
ASSERT(BP_IS_PROTECTED(bp));
|
|
error = SET_ERROR(EIO);
|
|
if ((zio->io_flags & ZIO_FLAG_SPECULATIVE) == 0) {
|
|
spa_log_error(zio->io_spa, &acb->acb_zb);
|
|
zfs_ereport_post(FM_EREPORT_ZFS_AUTHENTICATION,
|
|
zio->io_spa, NULL, &acb->acb_zb, zio, 0, 0);
|
|
}
|
|
}
|
|
|
|
if (error != 0) {
|
|
/*
|
|
* Decompression or decryption failed. Set
|
|
* io_error so that when we call acb_done
|
|
* (below), we will indicate that the read
|
|
* failed. Note that in the unusual case
|
|
* where one callback is compressed and another
|
|
* uncompressed, we will mark all of them
|
|
* as failed, even though the uncompressed
|
|
* one can't actually fail. In this case,
|
|
* the hdr will not be anonymous, because
|
|
* if there are multiple callbacks, it's
|
|
* because multiple threads found the same
|
|
* arc buf in the hash table.
|
|
*/
|
|
zio->io_error = error;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If there are multiple callbacks, we must have the hash lock,
|
|
* because the only way for multiple threads to find this hdr is
|
|
* in the hash table. This ensures that if there are multiple
|
|
* callbacks, the hdr is not anonymous. If it were anonymous,
|
|
* we couldn't use arc_buf_destroy() in the error case below.
|
|
*/
|
|
ASSERT(callback_cnt < 2 || hash_lock != NULL);
|
|
|
|
hdr->b_l1hdr.b_acb = NULL;
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS);
|
|
if (callback_cnt == 0)
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr));
|
|
|
|
ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt) ||
|
|
callback_list != NULL);
|
|
|
|
if (zio->io_error == 0) {
|
|
arc_hdr_verify(hdr, zio->io_bp);
|
|
} else {
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR);
|
|
if (hdr->b_l1hdr.b_state != arc_anon)
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
if (HDR_IN_HASH_TABLE(hdr))
|
|
buf_hash_remove(hdr);
|
|
freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt);
|
|
}
|
|
|
|
/*
|
|
* Broadcast before we drop the hash_lock to avoid the possibility
|
|
* that the hdr (and hence the cv) might be freed before we get to
|
|
* the cv_broadcast().
|
|
*/
|
|
cv_broadcast(&hdr->b_l1hdr.b_cv);
|
|
|
|
if (hash_lock != NULL) {
|
|
mutex_exit(hash_lock);
|
|
} else {
|
|
/*
|
|
* This block was freed while we waited for the read to
|
|
* complete. It has been removed from the hash table and
|
|
* moved to the anonymous state (so that it won't show up
|
|
* in the cache).
|
|
*/
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt);
|
|
}
|
|
|
|
/* execute each callback and free its structure */
|
|
while ((acb = callback_list) != NULL) {
|
|
if (acb->acb_done != NULL) {
|
|
if (zio->io_error != 0 && acb->acb_buf != NULL) {
|
|
/*
|
|
* If arc_buf_alloc_impl() fails during
|
|
* decompression, the buf will still be
|
|
* allocated, and needs to be freed here.
|
|
*/
|
|
arc_buf_destroy(acb->acb_buf,
|
|
acb->acb_private);
|
|
acb->acb_buf = NULL;
|
|
}
|
|
acb->acb_done(zio, &zio->io_bookmark, zio->io_bp,
|
|
acb->acb_buf, acb->acb_private);
|
|
}
|
|
|
|
if (acb->acb_zio_dummy != NULL) {
|
|
acb->acb_zio_dummy->io_error = zio->io_error;
|
|
zio_nowait(acb->acb_zio_dummy);
|
|
}
|
|
|
|
callback_list = acb->acb_next;
|
|
kmem_free(acb, sizeof (arc_callback_t));
|
|
}
|
|
|
|
if (freeable)
|
|
arc_hdr_destroy(hdr);
|
|
}
|
|
|
|
/*
|
|
* "Read" the block at the specified DVA (in bp) via the
|
|
* cache. If the block is found in the cache, invoke the provided
|
|
* callback immediately and return. Note that the `zio' parameter
|
|
* in the callback will be NULL in this case, since no IO was
|
|
* required. If the block is not in the cache pass the read request
|
|
* on to the spa with a substitute callback function, so that the
|
|
* requested block will be added to the cache.
|
|
*
|
|
* If a read request arrives for a block that has a read in-progress,
|
|
* either wait for the in-progress read to complete (and return the
|
|
* results); or, if this is a read with a "done" func, add a record
|
|
* to the read to invoke the "done" func when the read completes,
|
|
* and return; or just return.
|
|
*
|
|
* arc_read_done() will invoke all the requested "done" functions
|
|
* for readers of this block.
|
|
*/
|
|
int
|
|
arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
|
|
arc_read_done_func_t *done, void *private, zio_priority_t priority,
|
|
int zio_flags, arc_flags_t *arc_flags, const zbookmark_phys_t *zb)
|
|
{
|
|
arc_buf_hdr_t *hdr = NULL;
|
|
kmutex_t *hash_lock = NULL;
|
|
zio_t *rzio;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
boolean_t compressed_read = (zio_flags & ZIO_FLAG_RAW_COMPRESS) != 0;
|
|
boolean_t encrypted_read = BP_IS_ENCRYPTED(bp) &&
|
|
(zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0;
|
|
boolean_t noauth_read = BP_IS_AUTHENTICATED(bp) &&
|
|
(zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0;
|
|
boolean_t embedded_bp = !!BP_IS_EMBEDDED(bp);
|
|
int rc = 0;
|
|
|
|
ASSERT(!embedded_bp ||
|
|
BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);
|
|
ASSERT(!BP_IS_HOLE(bp));
|
|
ASSERT(!BP_IS_REDACTED(bp));
|
|
|
|
/*
|
|
* Normally SPL_FSTRANS will already be set since kernel threads which
|
|
* expect to call the DMU interfaces will set it when created. System
|
|
* calls are similarly handled by setting/cleaning the bit in the
|
|
* registered callback (module/os/.../zfs/zpl_*).
|
|
*
|
|
* External consumers such as Lustre which call the exported DMU
|
|
* interfaces may not have set SPL_FSTRANS. To avoid a deadlock
|
|
* on the hash_lock always set and clear the bit.
|
|
*/
|
|
fstrans_cookie_t cookie = spl_fstrans_mark();
|
|
top:
|
|
if (!embedded_bp) {
|
|
/*
|
|
* Embedded BP's have no DVA and require no I/O to "read".
|
|
* Create an anonymous arc buf to back it.
|
|
*/
|
|
hdr = buf_hash_find(guid, bp, &hash_lock);
|
|
}
|
|
|
|
/*
|
|
* Determine if we have an L1 cache hit or a cache miss. For simplicity
|
|
* we maintain encrypted data separately from compressed / uncompressed
|
|
* data. If the user is requesting raw encrypted data and we don't have
|
|
* that in the header we will read from disk to guarantee that we can
|
|
* get it even if the encryption keys aren't loaded.
|
|
*/
|
|
if (hdr != NULL && HDR_HAS_L1HDR(hdr) && (HDR_HAS_RABD(hdr) ||
|
|
(hdr->b_l1hdr.b_pabd != NULL && !encrypted_read))) {
|
|
arc_buf_t *buf = NULL;
|
|
*arc_flags |= ARC_FLAG_CACHED;
|
|
|
|
if (HDR_IO_IN_PROGRESS(hdr)) {
|
|
zio_t *head_zio = hdr->b_l1hdr.b_acb->acb_zio_head;
|
|
|
|
if (*arc_flags & ARC_FLAG_CACHED_ONLY) {
|
|
mutex_exit(hash_lock);
|
|
ARCSTAT_BUMP(arcstat_cached_only_in_progress);
|
|
rc = SET_ERROR(ENOENT);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT3P(head_zio, !=, NULL);
|
|
if ((hdr->b_flags & ARC_FLAG_PRIO_ASYNC_READ) &&
|
|
priority == ZIO_PRIORITY_SYNC_READ) {
|
|
/*
|
|
* This is a sync read that needs to wait for
|
|
* an in-flight async read. Request that the
|
|
* zio have its priority upgraded.
|
|
*/
|
|
zio_change_priority(head_zio, priority);
|
|
DTRACE_PROBE1(arc__async__upgrade__sync,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_async_upgrade_sync);
|
|
}
|
|
if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) {
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_PREDICTIVE_PREFETCH);
|
|
}
|
|
|
|
if (*arc_flags & ARC_FLAG_WAIT) {
|
|
cv_wait(&hdr->b_l1hdr.b_cv, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
ASSERT(*arc_flags & ARC_FLAG_NOWAIT);
|
|
|
|
if (done) {
|
|
arc_callback_t *acb = NULL;
|
|
|
|
acb = kmem_zalloc(sizeof (arc_callback_t),
|
|
KM_SLEEP);
|
|
acb->acb_done = done;
|
|
acb->acb_private = private;
|
|
acb->acb_compressed = compressed_read;
|
|
acb->acb_encrypted = encrypted_read;
|
|
acb->acb_noauth = noauth_read;
|
|
acb->acb_zb = *zb;
|
|
if (pio != NULL)
|
|
acb->acb_zio_dummy = zio_null(pio,
|
|
spa, NULL, NULL, NULL, zio_flags);
|
|
|
|
ASSERT3P(acb->acb_done, !=, NULL);
|
|
acb->acb_zio_head = head_zio;
|
|
acb->acb_next = hdr->b_l1hdr.b_acb;
|
|
hdr->b_l1hdr.b_acb = acb;
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
|
|
hdr->b_l1hdr.b_state == arc_mfu);
|
|
|
|
if (done) {
|
|
if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) {
|
|
/*
|
|
* This is a demand read which does not have to
|
|
* wait for i/o because we did a predictive
|
|
* prefetch i/o for it, which has completed.
|
|
*/
|
|
DTRACE_PROBE1(
|
|
arc__demand__hit__predictive__prefetch,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(
|
|
arcstat_demand_hit_predictive_prefetch);
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_PREDICTIVE_PREFETCH);
|
|
}
|
|
|
|
if (hdr->b_flags & ARC_FLAG_PRESCIENT_PREFETCH) {
|
|
ARCSTAT_BUMP(
|
|
arcstat_demand_hit_prescient_prefetch);
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_PRESCIENT_PREFETCH);
|
|
}
|
|
|
|
ASSERT(!embedded_bp || !BP_IS_HOLE(bp));
|
|
|
|
/* Get a buf with the desired data in it. */
|
|
rc = arc_buf_alloc_impl(hdr, spa, zb, private,
|
|
encrypted_read, compressed_read, noauth_read,
|
|
B_TRUE, &buf);
|
|
if (rc == ECKSUM) {
|
|
/*
|
|
* Convert authentication and decryption errors
|
|
* to EIO (and generate an ereport if needed)
|
|
* before leaving the ARC.
|
|
*/
|
|
rc = SET_ERROR(EIO);
|
|
if ((zio_flags & ZIO_FLAG_SPECULATIVE) == 0) {
|
|
spa_log_error(spa, zb);
|
|
zfs_ereport_post(
|
|
FM_EREPORT_ZFS_AUTHENTICATION,
|
|
spa, NULL, zb, NULL, 0, 0);
|
|
}
|
|
}
|
|
if (rc != 0) {
|
|
(void) remove_reference(hdr, hash_lock,
|
|
private);
|
|
arc_buf_destroy_impl(buf);
|
|
buf = NULL;
|
|
}
|
|
|
|
/* assert any errors weren't due to unloaded keys */
|
|
ASSERT((zio_flags & ZIO_FLAG_SPECULATIVE) ||
|
|
rc != EACCES);
|
|
} else if (*arc_flags & ARC_FLAG_PREFETCH &&
|
|
zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) {
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH);
|
|
}
|
|
DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr);
|
|
arc_access(hdr, hash_lock);
|
|
if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH);
|
|
if (*arc_flags & ARC_FLAG_L2CACHE)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE);
|
|
mutex_exit(hash_lock);
|
|
ARCSTAT_BUMP(arcstat_hits);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr),
|
|
data, metadata, hits);
|
|
|
|
if (done)
|
|
done(NULL, zb, bp, buf, private);
|
|
} else {
|
|
uint64_t lsize = BP_GET_LSIZE(bp);
|
|
uint64_t psize = BP_GET_PSIZE(bp);
|
|
arc_callback_t *acb;
|
|
vdev_t *vd = NULL;
|
|
uint64_t addr = 0;
|
|
boolean_t devw = B_FALSE;
|
|
uint64_t size;
|
|
abd_t *hdr_abd;
|
|
int alloc_flags = encrypted_read ? ARC_HDR_ALLOC_RDATA : 0;
|
|
|
|
if (*arc_flags & ARC_FLAG_CACHED_ONLY) {
|
|
rc = SET_ERROR(ENOENT);
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Gracefully handle a damaged logical block size as a
|
|
* checksum error.
|
|
*/
|
|
if (lsize > spa_maxblocksize(spa)) {
|
|
rc = SET_ERROR(ECKSUM);
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
|
|
if (hdr == NULL) {
|
|
/*
|
|
* This block is not in the cache or it has
|
|
* embedded data.
|
|
*/
|
|
arc_buf_hdr_t *exists = NULL;
|
|
arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp);
|
|
hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize,
|
|
BP_IS_PROTECTED(bp), BP_GET_COMPRESS(bp), 0, type,
|
|
encrypted_read);
|
|
|
|
if (!embedded_bp) {
|
|
hdr->b_dva = *BP_IDENTITY(bp);
|
|
hdr->b_birth = BP_PHYSICAL_BIRTH(bp);
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
}
|
|
if (exists != NULL) {
|
|
/* somebody beat us to the hash insert */
|
|
mutex_exit(hash_lock);
|
|
buf_discard_identity(hdr);
|
|
arc_hdr_destroy(hdr);
|
|
goto top; /* restart the IO request */
|
|
}
|
|
} else {
|
|
/*
|
|
* This block is in the ghost cache or encrypted data
|
|
* was requested and we didn't have it. If it was
|
|
* L2-only (and thus didn't have an L1 hdr),
|
|
* we realloc the header to add an L1 hdr.
|
|
*/
|
|
if (!HDR_HAS_L1HDR(hdr)) {
|
|
hdr = arc_hdr_realloc(hdr, hdr_l2only_cache,
|
|
hdr_full_cache);
|
|
}
|
|
|
|
if (GHOST_STATE(hdr->b_l1hdr.b_state)) {
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT0(zfs_refcount_count(
|
|
&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL);
|
|
} else if (HDR_IO_IN_PROGRESS(hdr)) {
|
|
/*
|
|
* If this header already had an IO in progress
|
|
* and we are performing another IO to fetch
|
|
* encrypted data we must wait until the first
|
|
* IO completes so as not to confuse
|
|
* arc_read_done(). This should be very rare
|
|
* and so the performance impact shouldn't
|
|
* matter.
|
|
*/
|
|
cv_wait(&hdr->b_l1hdr.b_cv, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
|
|
/*
|
|
* This is a delicate dance that we play here.
|
|
* This hdr might be in the ghost list so we access
|
|
* it to move it out of the ghost list before we
|
|
* initiate the read. If it's a prefetch then
|
|
* it won't have a callback so we'll remove the
|
|
* reference that arc_buf_alloc_impl() created. We
|
|
* do this after we've called arc_access() to
|
|
* avoid hitting an assert in remove_reference().
|
|
*/
|
|
arc_adapt(arc_hdr_size(hdr), hdr->b_l1hdr.b_state);
|
|
arc_access(hdr, hash_lock);
|
|
arc_hdr_alloc_abd(hdr, alloc_flags);
|
|
}
|
|
|
|
if (encrypted_read) {
|
|
ASSERT(HDR_HAS_RABD(hdr));
|
|
size = HDR_GET_PSIZE(hdr);
|
|
hdr_abd = hdr->b_crypt_hdr.b_rabd;
|
|
zio_flags |= ZIO_FLAG_RAW;
|
|
} else {
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
size = arc_hdr_size(hdr);
|
|
hdr_abd = hdr->b_l1hdr.b_pabd;
|
|
|
|
if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) {
|
|
zio_flags |= ZIO_FLAG_RAW_COMPRESS;
|
|
}
|
|
|
|
/*
|
|
* For authenticated bp's, we do not ask the ZIO layer
|
|
* to authenticate them since this will cause the entire
|
|
* IO to fail if the key isn't loaded. Instead, we
|
|
* defer authentication until arc_buf_fill(), which will
|
|
* verify the data when the key is available.
|
|
*/
|
|
if (BP_IS_AUTHENTICATED(bp))
|
|
zio_flags |= ZIO_FLAG_RAW_ENCRYPT;
|
|
}
|
|
|
|
if (*arc_flags & ARC_FLAG_PREFETCH &&
|
|
zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt))
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH);
|
|
if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH);
|
|
if (*arc_flags & ARC_FLAG_L2CACHE)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE);
|
|
if (BP_IS_AUTHENTICATED(bp))
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH);
|
|
if (BP_GET_LEVEL(bp) > 0)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_INDIRECT);
|
|
if (*arc_flags & ARC_FLAG_PREDICTIVE_PREFETCH)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PREDICTIVE_PREFETCH);
|
|
ASSERT(!GHOST_STATE(hdr->b_l1hdr.b_state));
|
|
|
|
acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP);
|
|
acb->acb_done = done;
|
|
acb->acb_private = private;
|
|
acb->acb_compressed = compressed_read;
|
|
acb->acb_encrypted = encrypted_read;
|
|
acb->acb_noauth = noauth_read;
|
|
acb->acb_zb = *zb;
|
|
|
|
ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL);
|
|
hdr->b_l1hdr.b_acb = acb;
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS);
|
|
|
|
if (HDR_HAS_L2HDR(hdr) &&
|
|
(vd = hdr->b_l2hdr.b_dev->l2ad_vdev) != NULL) {
|
|
devw = hdr->b_l2hdr.b_dev->l2ad_writing;
|
|
addr = hdr->b_l2hdr.b_daddr;
|
|
/*
|
|
* Lock out L2ARC device removal.
|
|
*/
|
|
if (vdev_is_dead(vd) ||
|
|
!spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER))
|
|
vd = NULL;
|
|
}
|
|
|
|
/*
|
|
* We count both async reads and scrub IOs as asynchronous so
|
|
* that both can be upgraded in the event of a cache hit while
|
|
* the read IO is still in-flight.
|
|
*/
|
|
if (priority == ZIO_PRIORITY_ASYNC_READ ||
|
|
priority == ZIO_PRIORITY_SCRUB)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ);
|
|
else
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ);
|
|
|
|
/*
|
|
* At this point, we have a level 1 cache miss or a blkptr
|
|
* with embedded data. Try again in L2ARC if possible.
|
|
*/
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), ==, lsize);
|
|
|
|
/*
|
|
* Skip ARC stat bump for block pointers with embedded
|
|
* data. The data are read from the blkptr itself via
|
|
* decode_embedded_bp_compressed().
|
|
*/
|
|
if (!embedded_bp) {
|
|
DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr,
|
|
blkptr_t *, bp, uint64_t, lsize,
|
|
zbookmark_phys_t *, zb);
|
|
ARCSTAT_BUMP(arcstat_misses);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data,
|
|
metadata, misses);
|
|
}
|
|
|
|
if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) {
|
|
/*
|
|
* Read from the L2ARC if the following are true:
|
|
* 1. The L2ARC vdev was previously cached.
|
|
* 2. This buffer still has L2ARC metadata.
|
|
* 3. This buffer isn't currently writing to the L2ARC.
|
|
* 4. The L2ARC entry wasn't evicted, which may
|
|
* also have invalidated the vdev.
|
|
* 5. This isn't prefetch and l2arc_noprefetch is set.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr) &&
|
|
!HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) &&
|
|
!(l2arc_noprefetch && HDR_PREFETCH(hdr))) {
|
|
l2arc_read_callback_t *cb;
|
|
abd_t *abd;
|
|
uint64_t asize;
|
|
|
|
DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_hits);
|
|
atomic_inc_32(&hdr->b_l2hdr.b_hits);
|
|
|
|
cb = kmem_zalloc(sizeof (l2arc_read_callback_t),
|
|
KM_SLEEP);
|
|
cb->l2rcb_hdr = hdr;
|
|
cb->l2rcb_bp = *bp;
|
|
cb->l2rcb_zb = *zb;
|
|
cb->l2rcb_flags = zio_flags;
|
|
|
|
/*
|
|
* When Compressed ARC is disabled, but the
|
|
* L2ARC block is compressed, arc_hdr_size()
|
|
* will have returned LSIZE rather than PSIZE.
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
|
|
!HDR_COMPRESSION_ENABLED(hdr) &&
|
|
HDR_GET_PSIZE(hdr) != 0) {
|
|
size = HDR_GET_PSIZE(hdr);
|
|
}
|
|
|
|
asize = vdev_psize_to_asize(vd, size);
|
|
if (asize != size) {
|
|
abd = abd_alloc_for_io(asize,
|
|
HDR_ISTYPE_METADATA(hdr));
|
|
cb->l2rcb_abd = abd;
|
|
} else {
|
|
abd = hdr_abd;
|
|
}
|
|
|
|
ASSERT(addr >= VDEV_LABEL_START_SIZE &&
|
|
addr + asize <= vd->vdev_psize -
|
|
VDEV_LABEL_END_SIZE);
|
|
|
|
/*
|
|
* l2arc read. The SCL_L2ARC lock will be
|
|
* released by l2arc_read_done().
|
|
* Issue a null zio if the underlying buffer
|
|
* was squashed to zero size by compression.
|
|
*/
|
|
ASSERT3U(arc_hdr_get_compress(hdr), !=,
|
|
ZIO_COMPRESS_EMPTY);
|
|
rzio = zio_read_phys(pio, vd, addr,
|
|
asize, abd,
|
|
ZIO_CHECKSUM_OFF,
|
|
l2arc_read_done, cb, priority,
|
|
zio_flags | ZIO_FLAG_DONT_CACHE |
|
|
ZIO_FLAG_CANFAIL |
|
|
ZIO_FLAG_DONT_PROPAGATE |
|
|
ZIO_FLAG_DONT_RETRY, B_FALSE);
|
|
acb->acb_zio_head = rzio;
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
DTRACE_PROBE2(l2arc__read, vdev_t *, vd,
|
|
zio_t *, rzio);
|
|
ARCSTAT_INCR(arcstat_l2_read_bytes,
|
|
HDR_GET_PSIZE(hdr));
|
|
|
|
if (*arc_flags & ARC_FLAG_NOWAIT) {
|
|
zio_nowait(rzio);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(*arc_flags & ARC_FLAG_WAIT);
|
|
if (zio_wait(rzio) == 0)
|
|
goto out;
|
|
|
|
/* l2arc read error; goto zio_read() */
|
|
if (hash_lock != NULL)
|
|
mutex_enter(hash_lock);
|
|
} else {
|
|
DTRACE_PROBE1(l2arc__miss,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_misses);
|
|
if (HDR_L2_WRITING(hdr))
|
|
ARCSTAT_BUMP(arcstat_l2_rw_clash);
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
}
|
|
} else {
|
|
if (vd != NULL)
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
/*
|
|
* Skip ARC stat bump for block pointers with
|
|
* embedded data. The data are read from the blkptr
|
|
* itself via decode_embedded_bp_compressed().
|
|
*/
|
|
if (l2arc_ndev != 0 && !embedded_bp) {
|
|
DTRACE_PROBE1(l2arc__miss,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_misses);
|
|
}
|
|
}
|
|
|
|
rzio = zio_read(pio, spa, bp, hdr_abd, size,
|
|
arc_read_done, hdr, priority, zio_flags, zb);
|
|
acb->acb_zio_head = rzio;
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
if (*arc_flags & ARC_FLAG_WAIT) {
|
|
rc = zio_wait(rzio);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(*arc_flags & ARC_FLAG_NOWAIT);
|
|
zio_nowait(rzio);
|
|
}
|
|
|
|
out:
|
|
/* embedded bps don't actually go to disk */
|
|
if (!embedded_bp)
|
|
spa_read_history_add(spa, zb, *arc_flags);
|
|
spl_fstrans_unmark(cookie);
|
|
return (rc);
|
|
}
|
|
|
|
arc_prune_t *
|
|
arc_add_prune_callback(arc_prune_func_t *func, void *private)
|
|
{
|
|
arc_prune_t *p;
|
|
|
|
p = kmem_alloc(sizeof (*p), KM_SLEEP);
|
|
p->p_pfunc = func;
|
|
p->p_private = private;
|
|
list_link_init(&p->p_node);
|
|
zfs_refcount_create(&p->p_refcnt);
|
|
|
|
mutex_enter(&arc_prune_mtx);
|
|
zfs_refcount_add(&p->p_refcnt, &arc_prune_list);
|
|
list_insert_head(&arc_prune_list, p);
|
|
mutex_exit(&arc_prune_mtx);
|
|
|
|
return (p);
|
|
}
|
|
|
|
void
|
|
arc_remove_prune_callback(arc_prune_t *p)
|
|
{
|
|
boolean_t wait = B_FALSE;
|
|
mutex_enter(&arc_prune_mtx);
|
|
list_remove(&arc_prune_list, p);
|
|
if (zfs_refcount_remove(&p->p_refcnt, &arc_prune_list) > 0)
|
|
wait = B_TRUE;
|
|
mutex_exit(&arc_prune_mtx);
|
|
|
|
/* wait for arc_prune_task to finish */
|
|
if (wait)
|
|
taskq_wait_outstanding(arc_prune_taskq, 0);
|
|
ASSERT0(zfs_refcount_count(&p->p_refcnt));
|
|
zfs_refcount_destroy(&p->p_refcnt);
|
|
kmem_free(p, sizeof (*p));
|
|
}
|
|
|
|
/*
|
|
* Notify the arc that a block was freed, and thus will never be used again.
|
|
*/
|
|
void
|
|
arc_freed(spa_t *spa, const blkptr_t *bp)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
|
|
ASSERT(!BP_IS_EMBEDDED(bp));
|
|
|
|
hdr = buf_hash_find(guid, bp, &hash_lock);
|
|
if (hdr == NULL)
|
|
return;
|
|
|
|
/*
|
|
* We might be trying to free a block that is still doing I/O
|
|
* (i.e. prefetch) or has a reference (i.e. a dedup-ed,
|
|
* dmu_sync-ed block). If this block is being prefetched, then it
|
|
* would still have the ARC_FLAG_IO_IN_PROGRESS flag set on the hdr
|
|
* until the I/O completes. A block may also have a reference if it is
|
|
* part of a dedup-ed, dmu_synced write. The dmu_sync() function would
|
|
* have written the new block to its final resting place on disk but
|
|
* without the dedup flag set. This would have left the hdr in the MRU
|
|
* state and discoverable. When the txg finally syncs it detects that
|
|
* the block was overridden in open context and issues an override I/O.
|
|
* Since this is a dedup block, the override I/O will determine if the
|
|
* block is already in the DDT. If so, then it will replace the io_bp
|
|
* with the bp from the DDT and allow the I/O to finish. When the I/O
|
|
* reaches the done callback, dbuf_write_override_done, it will
|
|
* check to see if the io_bp and io_bp_override are identical.
|
|
* If they are not, then it indicates that the bp was replaced with
|
|
* the bp in the DDT and the override bp is freed. This allows
|
|
* us to arrive here with a reference on a block that is being
|
|
* freed. So if we have an I/O in progress, or a reference to
|
|
* this hdr, then we don't destroy the hdr.
|
|
*/
|
|
if (!HDR_HAS_L1HDR(hdr) || (!HDR_IO_IN_PROGRESS(hdr) &&
|
|
zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt))) {
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
arc_hdr_destroy(hdr);
|
|
mutex_exit(hash_lock);
|
|
} else {
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
* Release this buffer from the cache, making it an anonymous buffer. This
|
|
* must be done after a read and prior to modifying the buffer contents.
|
|
* If the buffer has more than one reference, we must make
|
|
* a new hdr for the buffer.
|
|
*/
|
|
void
|
|
arc_release(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
/*
|
|
* It would be nice to assert that if its DMU metadata (level >
|
|
* 0 || it's the dnode file), then it must be syncing context.
|
|
* But we don't know that information at this level.
|
|
*/
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
/*
|
|
* We don't grab the hash lock prior to this check, because if
|
|
* the buffer's header is in the arc_anon state, it won't be
|
|
* linked into the hash table.
|
|
*/
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
ASSERT(!HDR_HAS_L2HDR(hdr));
|
|
ASSERT(HDR_EMPTY(hdr));
|
|
|
|
ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1);
|
|
ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), ==, 1);
|
|
ASSERT(!list_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
|
|
/*
|
|
* If the buf is being overridden then it may already
|
|
* have a hdr that is not empty.
|
|
*/
|
|
buf_discard_identity(hdr);
|
|
arc_buf_thaw(buf);
|
|
|
|
return;
|
|
}
|
|
|
|
kmutex_t *hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
|
|
/*
|
|
* This assignment is only valid as long as the hash_lock is
|
|
* held, we must be careful not to reference state or the
|
|
* b_state field after dropping the lock.
|
|
*/
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
ASSERT3P(state, !=, arc_anon);
|
|
|
|
/* this buffer is not on any list */
|
|
ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), >, 0);
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
mutex_enter(&hdr->b_l2hdr.b_dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We have to recheck this conditional again now that
|
|
* we're holding the l2ad_mtx to prevent a race with
|
|
* another thread which might be concurrently calling
|
|
* l2arc_evict(). In that case, l2arc_evict() might have
|
|
* destroyed the header's L2 portion as we were waiting
|
|
* to acquire the l2ad_mtx.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
|
|
mutex_exit(&hdr->b_l2hdr.b_dev->l2ad_mtx);
|
|
}
|
|
|
|
/*
|
|
* Do we have more than one buf?
|
|
*/
|
|
if (hdr->b_l1hdr.b_bufcnt > 1) {
|
|
arc_buf_hdr_t *nhdr;
|
|
uint64_t spa = hdr->b_spa;
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
uint64_t lsize = HDR_GET_LSIZE(hdr);
|
|
boolean_t protected = HDR_PROTECTED(hdr);
|
|
enum zio_compress compress = arc_hdr_get_compress(hdr);
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
VERIFY3U(hdr->b_type, ==, type);
|
|
|
|
ASSERT(hdr->b_l1hdr.b_buf != buf || buf->b_next != NULL);
|
|
(void) remove_reference(hdr, hash_lock, tag);
|
|
|
|
if (arc_buf_is_shared(buf) && !ARC_BUF_COMPRESSED(buf)) {
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf);
|
|
ASSERT(ARC_BUF_LAST(buf));
|
|
}
|
|
|
|
/*
|
|
* Pull the data off of this hdr and attach it to
|
|
* a new anonymous hdr. Also find the last buffer
|
|
* in the hdr's buffer list.
|
|
*/
|
|
arc_buf_t *lastbuf = arc_buf_remove(hdr, buf);
|
|
ASSERT3P(lastbuf, !=, NULL);
|
|
|
|
/*
|
|
* If the current arc_buf_t and the hdr are sharing their data
|
|
* buffer, then we must stop sharing that block.
|
|
*/
|
|
if (arc_buf_is_shared(buf)) {
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf);
|
|
VERIFY(!arc_buf_is_shared(lastbuf));
|
|
|
|
/*
|
|
* First, sever the block sharing relationship between
|
|
* buf and the arc_buf_hdr_t.
|
|
*/
|
|
arc_unshare_buf(hdr, buf);
|
|
|
|
/*
|
|
* Now we need to recreate the hdr's b_pabd. Since we
|
|
* have lastbuf handy, we try to share with it, but if
|
|
* we can't then we allocate a new b_pabd and copy the
|
|
* data from buf into it.
|
|
*/
|
|
if (arc_can_share(hdr, lastbuf)) {
|
|
arc_share_buf(hdr, lastbuf);
|
|
} else {
|
|
arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT);
|
|
abd_copy_from_buf(hdr->b_l1hdr.b_pabd,
|
|
buf->b_data, psize);
|
|
}
|
|
VERIFY3P(lastbuf->b_data, !=, NULL);
|
|
} else if (HDR_SHARED_DATA(hdr)) {
|
|
/*
|
|
* Uncompressed shared buffers are always at the end
|
|
* of the list. Compressed buffers don't have the
|
|
* same requirements. This makes it hard to
|
|
* simply assert that the lastbuf is shared so
|
|
* we rely on the hdr's compression flags to determine
|
|
* if we have a compressed, shared buffer.
|
|
*/
|
|
ASSERT(arc_buf_is_shared(lastbuf) ||
|
|
arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF);
|
|
ASSERT(!ARC_BUF_SHARED(buf));
|
|
}
|
|
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr));
|
|
ASSERT3P(state, !=, arc_l2c_only);
|
|
|
|
(void) zfs_refcount_remove_many(&state->arcs_size,
|
|
arc_buf_size(buf), buf);
|
|
|
|
if (zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) {
|
|
ASSERT3P(state, !=, arc_l2c_only);
|
|
(void) zfs_refcount_remove_many(
|
|
&state->arcs_esize[type],
|
|
arc_buf_size(buf), buf);
|
|
}
|
|
|
|
hdr->b_l1hdr.b_bufcnt -= 1;
|
|
if (ARC_BUF_ENCRYPTED(buf))
|
|
hdr->b_crypt_hdr.b_ebufcnt -= 1;
|
|
|
|
arc_cksum_verify(buf);
|
|
arc_buf_unwatch(buf);
|
|
|
|
/* if this is the last uncompressed buf free the checksum */
|
|
if (!arc_hdr_has_uncompressed_buf(hdr))
|
|
arc_cksum_free(hdr);
|
|
|
|
mutex_exit(hash_lock);
|
|
|
|
/*
|
|
* Allocate a new hdr. The new hdr will contain a b_pabd
|
|
* buffer which will be freed in arc_write().
|
|
*/
|
|
nhdr = arc_hdr_alloc(spa, psize, lsize, protected,
|
|
compress, hdr->b_complevel, type, HDR_HAS_RABD(hdr));
|
|
ASSERT3P(nhdr->b_l1hdr.b_buf, ==, NULL);
|
|
ASSERT0(nhdr->b_l1hdr.b_bufcnt);
|
|
ASSERT0(zfs_refcount_count(&nhdr->b_l1hdr.b_refcnt));
|
|
VERIFY3U(nhdr->b_type, ==, type);
|
|
ASSERT(!HDR_SHARED_DATA(nhdr));
|
|
|
|
nhdr->b_l1hdr.b_buf = buf;
|
|
nhdr->b_l1hdr.b_bufcnt = 1;
|
|
if (ARC_BUF_ENCRYPTED(buf))
|
|
nhdr->b_crypt_hdr.b_ebufcnt = 1;
|
|
nhdr->b_l1hdr.b_mru_hits = 0;
|
|
nhdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
nhdr->b_l1hdr.b_mfu_hits = 0;
|
|
nhdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
nhdr->b_l1hdr.b_l2_hits = 0;
|
|
(void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, tag);
|
|
buf->b_hdr = nhdr;
|
|
|
|
mutex_exit(&buf->b_evict_lock);
|
|
(void) zfs_refcount_add_many(&arc_anon->arcs_size,
|
|
arc_buf_size(buf), buf);
|
|
} else {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
ASSERT(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 1);
|
|
/* protected by hash lock, or hdr is on arc_anon */
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
hdr->b_l1hdr.b_mru_hits = 0;
|
|
hdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_l2_hits = 0;
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
|
|
mutex_exit(hash_lock);
|
|
buf_discard_identity(hdr);
|
|
arc_buf_thaw(buf);
|
|
}
|
|
}
|
|
|
|
int
|
|
arc_released(arc_buf_t *buf)
|
|
{
|
|
int released;
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
released = (buf->b_data != NULL &&
|
|
buf->b_hdr->b_l1hdr.b_state == arc_anon);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (released);
|
|
}
|
|
|
|
#ifdef ZFS_DEBUG
|
|
int
|
|
arc_referenced(arc_buf_t *buf)
|
|
{
|
|
int referenced;
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
referenced = (zfs_refcount_count(&buf->b_hdr->b_l1hdr.b_refcnt));
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (referenced);
|
|
}
|
|
#endif
|
|
|
|
static void
|
|
arc_write_ready(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *callback = zio->io_private;
|
|
arc_buf_t *buf = callback->awcb_buf;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
blkptr_t *bp = zio->io_bp;
|
|
uint64_t psize = BP_IS_HOLE(bp) ? 0 : BP_GET_PSIZE(bp);
|
|
fstrans_cookie_t cookie = spl_fstrans_mark();
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(!zfs_refcount_is_zero(&buf->b_hdr->b_l1hdr.b_refcnt));
|
|
ASSERT(hdr->b_l1hdr.b_bufcnt > 0);
|
|
|
|
/*
|
|
* If we're reexecuting this zio because the pool suspended, then
|
|
* cleanup any state that was previously set the first time the
|
|
* callback was invoked.
|
|
*/
|
|
if (zio->io_flags & ZIO_FLAG_REEXECUTED) {
|
|
arc_cksum_free(hdr);
|
|
arc_buf_unwatch(buf);
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
if (arc_buf_is_shared(buf)) {
|
|
arc_unshare_buf(hdr, buf);
|
|
} else {
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
}
|
|
}
|
|
|
|
if (HDR_HAS_RABD(hdr))
|
|
arc_hdr_free_abd(hdr, B_TRUE);
|
|
}
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
ASSERT(!HDR_HAS_RABD(hdr));
|
|
ASSERT(!HDR_SHARED_DATA(hdr));
|
|
ASSERT(!arc_buf_is_shared(buf));
|
|
|
|
callback->awcb_ready(zio, buf, callback->awcb_private);
|
|
|
|
if (HDR_IO_IN_PROGRESS(hdr))
|
|
ASSERT(zio->io_flags & ZIO_FLAG_REEXECUTED);
|
|
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS);
|
|
|
|
if (BP_IS_PROTECTED(bp) != !!HDR_PROTECTED(hdr))
|
|
hdr = arc_hdr_realloc_crypt(hdr, BP_IS_PROTECTED(bp));
|
|
|
|
if (BP_IS_PROTECTED(bp)) {
|
|
/* ZIL blocks are written through zio_rewrite */
|
|
ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG);
|
|
ASSERT(HDR_PROTECTED(hdr));
|
|
|
|
if (BP_SHOULD_BYTESWAP(bp)) {
|
|
if (BP_GET_LEVEL(bp) > 0) {
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64;
|
|
} else {
|
|
hdr->b_l1hdr.b_byteswap =
|
|
DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
|
|
}
|
|
} else {
|
|
hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS;
|
|
}
|
|
|
|
hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp);
|
|
hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset;
|
|
zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt,
|
|
hdr->b_crypt_hdr.b_iv);
|
|
zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac);
|
|
}
|
|
|
|
/*
|
|
* If this block was written for raw encryption but the zio layer
|
|
* ended up only authenticating it, adjust the buffer flags now.
|
|
*/
|
|
if (BP_IS_AUTHENTICATED(bp) && ARC_BUF_ENCRYPTED(buf)) {
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH);
|
|
buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED;
|
|
if (BP_GET_COMPRESS(bp) == ZIO_COMPRESS_OFF)
|
|
buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
|
|
} else if (BP_IS_HOLE(bp) && ARC_BUF_ENCRYPTED(buf)) {
|
|
buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED;
|
|
buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED;
|
|
}
|
|
|
|
/* this must be done after the buffer flags are adjusted */
|
|
arc_cksum_compute(buf);
|
|
|
|
enum zio_compress compress;
|
|
if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) {
|
|
compress = ZIO_COMPRESS_OFF;
|
|
} else {
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp));
|
|
compress = BP_GET_COMPRESS(bp);
|
|
}
|
|
HDR_SET_PSIZE(hdr, psize);
|
|
arc_hdr_set_compress(hdr, compress);
|
|
hdr->b_complevel = zio->io_prop.zp_complevel;
|
|
|
|
if (zio->io_error != 0 || psize == 0)
|
|
goto out;
|
|
|
|
/*
|
|
* Fill the hdr with data. If the buffer is encrypted we have no choice
|
|
* but to copy the data into b_radb. If the hdr is compressed, the data
|
|
* we want is available from the zio, otherwise we can take it from
|
|
* the buf.
|
|
*
|
|
* We might be able to share the buf's data with the hdr here. However,
|
|
* doing so would cause the ARC to be full of linear ABDs if we write a
|
|
* lot of shareable data. As a compromise, we check whether scattered
|
|
* ABDs are allowed, and assume that if they are then the user wants
|
|
* the ARC to be primarily filled with them regardless of the data being
|
|
* written. Therefore, if they're allowed then we allocate one and copy
|
|
* the data into it; otherwise, we share the data directly if we can.
|
|
*/
|
|
if (ARC_BUF_ENCRYPTED(buf)) {
|
|
ASSERT3U(psize, >, 0);
|
|
ASSERT(ARC_BUF_COMPRESSED(buf));
|
|
arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT|ARC_HDR_ALLOC_RDATA);
|
|
abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize);
|
|
} else if (zfs_abd_scatter_enabled || !arc_can_share(hdr, buf)) {
|
|
/*
|
|
* Ideally, we would always copy the io_abd into b_pabd, but the
|
|
* user may have disabled compressed ARC, thus we must check the
|
|
* hdr's compression setting rather than the io_bp's.
|
|
*/
|
|
if (BP_IS_ENCRYPTED(bp)) {
|
|
ASSERT3U(psize, >, 0);
|
|
arc_hdr_alloc_abd(hdr,
|
|
ARC_HDR_DO_ADAPT|ARC_HDR_ALLOC_RDATA);
|
|
abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize);
|
|
} else if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF &&
|
|
!ARC_BUF_COMPRESSED(buf)) {
|
|
ASSERT3U(psize, >, 0);
|
|
arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT);
|
|
abd_copy(hdr->b_l1hdr.b_pabd, zio->io_abd, psize);
|
|
} else {
|
|
ASSERT3U(zio->io_orig_size, ==, arc_hdr_size(hdr));
|
|
arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT);
|
|
abd_copy_from_buf(hdr->b_l1hdr.b_pabd, buf->b_data,
|
|
arc_buf_size(buf));
|
|
}
|
|
} else {
|
|
ASSERT3P(buf->b_data, ==, abd_to_buf(zio->io_orig_abd));
|
|
ASSERT3U(zio->io_orig_size, ==, arc_buf_size(buf));
|
|
ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1);
|
|
|
|
arc_share_buf(hdr, buf);
|
|
}
|
|
|
|
out:
|
|
arc_hdr_verify(hdr, bp);
|
|
spl_fstrans_unmark(cookie);
|
|
}
|
|
|
|
static void
|
|
arc_write_children_ready(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *callback = zio->io_private;
|
|
arc_buf_t *buf = callback->awcb_buf;
|
|
|
|
callback->awcb_children_ready(zio, buf, callback->awcb_private);
|
|
}
|
|
|
|
/*
|
|
* The SPA calls this callback for each physical write that happens on behalf
|
|
* of a logical write. See the comment in dbuf_write_physdone() for details.
|
|
*/
|
|
static void
|
|
arc_write_physdone(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *cb = zio->io_private;
|
|
if (cb->awcb_physdone != NULL)
|
|
cb->awcb_physdone(zio, cb->awcb_buf, cb->awcb_private);
|
|
}
|
|
|
|
static void
|
|
arc_write_done(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *callback = zio->io_private;
|
|
arc_buf_t *buf = callback->awcb_buf;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL);
|
|
|
|
if (zio->io_error == 0) {
|
|
arc_hdr_verify(hdr, zio->io_bp);
|
|
|
|
if (BP_IS_HOLE(zio->io_bp) || BP_IS_EMBEDDED(zio->io_bp)) {
|
|
buf_discard_identity(hdr);
|
|
} else {
|
|
hdr->b_dva = *BP_IDENTITY(zio->io_bp);
|
|
hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp);
|
|
}
|
|
} else {
|
|
ASSERT(HDR_EMPTY(hdr));
|
|
}
|
|
|
|
/*
|
|
* If the block to be written was all-zero or compressed enough to be
|
|
* embedded in the BP, no write was performed so there will be no
|
|
* dva/birth/checksum. The buffer must therefore remain anonymous
|
|
* (and uncached).
|
|
*/
|
|
if (!HDR_EMPTY(hdr)) {
|
|
arc_buf_hdr_t *exists;
|
|
kmutex_t *hash_lock;
|
|
|
|
ASSERT3U(zio->io_error, ==, 0);
|
|
|
|
arc_cksum_verify(buf);
|
|
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
if (exists != NULL) {
|
|
/*
|
|
* This can only happen if we overwrite for
|
|
* sync-to-convergence, because we remove
|
|
* buffers from the hash table when we arc_free().
|
|
*/
|
|
if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
|
|
if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp))
|
|
panic("bad overwrite, hdr=%p exists=%p",
|
|
(void *)hdr, (void *)exists);
|
|
ASSERT(zfs_refcount_is_zero(
|
|
&exists->b_l1hdr.b_refcnt));
|
|
arc_change_state(arc_anon, exists, hash_lock);
|
|
arc_hdr_destroy(exists);
|
|
mutex_exit(hash_lock);
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
ASSERT3P(exists, ==, NULL);
|
|
} else if (zio->io_flags & ZIO_FLAG_NOPWRITE) {
|
|
/* nopwrite */
|
|
ASSERT(zio->io_prop.zp_nopwrite);
|
|
if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp))
|
|
panic("bad nopwrite, hdr=%p exists=%p",
|
|
(void *)hdr, (void *)exists);
|
|
} else {
|
|
/* Dedup */
|
|
ASSERT(hdr->b_l1hdr.b_bufcnt == 1);
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_anon);
|
|
ASSERT(BP_GET_DEDUP(zio->io_bp));
|
|
ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
|
|
}
|
|
}
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS);
|
|
/* if it's not anon, we are doing a scrub */
|
|
if (exists == NULL && hdr->b_l1hdr.b_state == arc_anon)
|
|
arc_access(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
} else {
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS);
|
|
}
|
|
|
|
ASSERT(!zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
callback->awcb_done(zio, buf, callback->awcb_private);
|
|
|
|
abd_put(zio->io_abd);
|
|
kmem_free(callback, sizeof (arc_write_callback_t));
|
|
}
|
|
|
|
zio_t *
|
|
arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
|
|
blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc,
|
|
const zio_prop_t *zp, arc_write_done_func_t *ready,
|
|
arc_write_done_func_t *children_ready, arc_write_done_func_t *physdone,
|
|
arc_write_done_func_t *done, void *private, zio_priority_t priority,
|
|
int zio_flags, const zbookmark_phys_t *zb)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
arc_write_callback_t *callback;
|
|
zio_t *zio;
|
|
zio_prop_t localprop = *zp;
|
|
|
|
ASSERT3P(ready, !=, NULL);
|
|
ASSERT3P(done, !=, NULL);
|
|
ASSERT(!HDR_IO_ERROR(hdr));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL);
|
|
ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0);
|
|
if (l2arc)
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE);
|
|
|
|
if (ARC_BUF_ENCRYPTED(buf)) {
|
|
ASSERT(ARC_BUF_COMPRESSED(buf));
|
|
localprop.zp_encrypt = B_TRUE;
|
|
localprop.zp_compress = HDR_GET_COMPRESS(hdr);
|
|
localprop.zp_complevel = hdr->b_complevel;
|
|
localprop.zp_byteorder =
|
|
(hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ?
|
|
ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER;
|
|
bcopy(hdr->b_crypt_hdr.b_salt, localprop.zp_salt,
|
|
ZIO_DATA_SALT_LEN);
|
|
bcopy(hdr->b_crypt_hdr.b_iv, localprop.zp_iv,
|
|
ZIO_DATA_IV_LEN);
|
|
bcopy(hdr->b_crypt_hdr.b_mac, localprop.zp_mac,
|
|
ZIO_DATA_MAC_LEN);
|
|
if (DMU_OT_IS_ENCRYPTED(localprop.zp_type)) {
|
|
localprop.zp_nopwrite = B_FALSE;
|
|
localprop.zp_copies =
|
|
MIN(localprop.zp_copies, SPA_DVAS_PER_BP - 1);
|
|
}
|
|
zio_flags |= ZIO_FLAG_RAW;
|
|
} else if (ARC_BUF_COMPRESSED(buf)) {
|
|
ASSERT3U(HDR_GET_LSIZE(hdr), !=, arc_buf_size(buf));
|
|
localprop.zp_compress = HDR_GET_COMPRESS(hdr);
|
|
localprop.zp_complevel = hdr->b_complevel;
|
|
zio_flags |= ZIO_FLAG_RAW_COMPRESS;
|
|
}
|
|
callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP);
|
|
callback->awcb_ready = ready;
|
|
callback->awcb_children_ready = children_ready;
|
|
callback->awcb_physdone = physdone;
|
|
callback->awcb_done = done;
|
|
callback->awcb_private = private;
|
|
callback->awcb_buf = buf;
|
|
|
|
/*
|
|
* The hdr's b_pabd is now stale, free it now. A new data block
|
|
* will be allocated when the zio pipeline calls arc_write_ready().
|
|
*/
|
|
if (hdr->b_l1hdr.b_pabd != NULL) {
|
|
/*
|
|
* If the buf is currently sharing the data block with
|
|
* the hdr then we need to break that relationship here.
|
|
* The hdr will remain with a NULL data pointer and the
|
|
* buf will take sole ownership of the block.
|
|
*/
|
|
if (arc_buf_is_shared(buf)) {
|
|
arc_unshare_buf(hdr, buf);
|
|
} else {
|
|
arc_hdr_free_abd(hdr, B_FALSE);
|
|
}
|
|
VERIFY3P(buf->b_data, !=, NULL);
|
|
}
|
|
|
|
if (HDR_HAS_RABD(hdr))
|
|
arc_hdr_free_abd(hdr, B_TRUE);
|
|
|
|
if (!(zio_flags & ZIO_FLAG_RAW))
|
|
arc_hdr_set_compress(hdr, ZIO_COMPRESS_OFF);
|
|
|
|
ASSERT(!arc_buf_is_shared(buf));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL);
|
|
|
|
zio = zio_write(pio, spa, txg, bp,
|
|
abd_get_from_buf(buf->b_data, HDR_GET_LSIZE(hdr)),
|
|
HDR_GET_LSIZE(hdr), arc_buf_size(buf), &localprop, arc_write_ready,
|
|
(children_ready != NULL) ? arc_write_children_ready : NULL,
|
|
arc_write_physdone, arc_write_done, callback,
|
|
priority, zio_flags, zb);
|
|
|
|
return (zio);
|
|
}
|
|
|
|
void
|
|
arc_tempreserve_clear(uint64_t reserve)
|
|
{
|
|
atomic_add_64(&arc_tempreserve, -reserve);
|
|
ASSERT((int64_t)arc_tempreserve >= 0);
|
|
}
|
|
|
|
int
|
|
arc_tempreserve_space(spa_t *spa, uint64_t reserve, uint64_t txg)
|
|
{
|
|
int error;
|
|
uint64_t anon_size;
|
|
|
|
if (!arc_no_grow &&
|
|
reserve > arc_c/4 &&
|
|
reserve * 4 > (2ULL << SPA_MAXBLOCKSHIFT))
|
|
arc_c = MIN(arc_c_max, reserve * 4);
|
|
|
|
/*
|
|
* Throttle when the calculated memory footprint for the TXG
|
|
* exceeds the target ARC size.
|
|
*/
|
|
if (reserve > arc_c) {
|
|
DMU_TX_STAT_BUMP(dmu_tx_memory_reserve);
|
|
return (SET_ERROR(ERESTART));
|
|
}
|
|
|
|
/*
|
|
* Don't count loaned bufs as in flight dirty data to prevent long
|
|
* network delays from blocking transactions that are ready to be
|
|
* assigned to a txg.
|
|
*/
|
|
|
|
/* assert that it has not wrapped around */
|
|
ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0);
|
|
|
|
anon_size = MAX((int64_t)(zfs_refcount_count(&arc_anon->arcs_size) -
|
|
arc_loaned_bytes), 0);
|
|
|
|
/*
|
|
* Writes will, almost always, require additional memory allocations
|
|
* in order to compress/encrypt/etc the data. We therefore need to
|
|
* make sure that there is sufficient available memory for this.
|
|
*/
|
|
error = arc_memory_throttle(spa, reserve, txg);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
/*
|
|
* Throttle writes when the amount of dirty data in the cache
|
|
* gets too large. We try to keep the cache less than half full
|
|
* of dirty blocks so that our sync times don't grow too large.
|
|
*
|
|
* In the case of one pool being built on another pool, we want
|
|
* to make sure we don't end up throttling the lower (backing)
|
|
* pool when the upper pool is the majority contributor to dirty
|
|
* data. To insure we make forward progress during throttling, we
|
|
* also check the current pool's net dirty data and only throttle
|
|
* if it exceeds zfs_arc_pool_dirty_percent of the anonymous dirty
|
|
* data in the cache.
|
|
*
|
|
* Note: if two requests come in concurrently, we might let them
|
|
* both succeed, when one of them should fail. Not a huge deal.
|
|
*/
|
|
uint64_t total_dirty = reserve + arc_tempreserve + anon_size;
|
|
uint64_t spa_dirty_anon = spa_dirty_data(spa);
|
|
|
|
if (total_dirty > arc_c * zfs_arc_dirty_limit_percent / 100 &&
|
|
anon_size > arc_c * zfs_arc_anon_limit_percent / 100 &&
|
|
spa_dirty_anon > anon_size * zfs_arc_pool_dirty_percent / 100) {
|
|
#ifdef ZFS_DEBUG
|
|
uint64_t meta_esize = zfs_refcount_count(
|
|
&arc_anon->arcs_esize[ARC_BUFC_METADATA]);
|
|
uint64_t data_esize =
|
|
zfs_refcount_count(&arc_anon->arcs_esize[ARC_BUFC_DATA]);
|
|
dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK "
|
|
"anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n",
|
|
arc_tempreserve >> 10, meta_esize >> 10,
|
|
data_esize >> 10, reserve >> 10, arc_c >> 10);
|
|
#endif
|
|
DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle);
|
|
return (SET_ERROR(ERESTART));
|
|
}
|
|
atomic_add_64(&arc_tempreserve, reserve);
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
arc_kstat_update_state(arc_state_t *state, kstat_named_t *size,
|
|
kstat_named_t *evict_data, kstat_named_t *evict_metadata)
|
|
{
|
|
size->value.ui64 = zfs_refcount_count(&state->arcs_size);
|
|
evict_data->value.ui64 =
|
|
zfs_refcount_count(&state->arcs_esize[ARC_BUFC_DATA]);
|
|
evict_metadata->value.ui64 =
|
|
zfs_refcount_count(&state->arcs_esize[ARC_BUFC_METADATA]);
|
|
}
|
|
|
|
static int
|
|
arc_kstat_update(kstat_t *ksp, int rw)
|
|
{
|
|
arc_stats_t *as = ksp->ks_data;
|
|
|
|
if (rw == KSTAT_WRITE) {
|
|
return (SET_ERROR(EACCES));
|
|
} else {
|
|
arc_kstat_update_state(arc_anon,
|
|
&as->arcstat_anon_size,
|
|
&as->arcstat_anon_evictable_data,
|
|
&as->arcstat_anon_evictable_metadata);
|
|
arc_kstat_update_state(arc_mru,
|
|
&as->arcstat_mru_size,
|
|
&as->arcstat_mru_evictable_data,
|
|
&as->arcstat_mru_evictable_metadata);
|
|
arc_kstat_update_state(arc_mru_ghost,
|
|
&as->arcstat_mru_ghost_size,
|
|
&as->arcstat_mru_ghost_evictable_data,
|
|
&as->arcstat_mru_ghost_evictable_metadata);
|
|
arc_kstat_update_state(arc_mfu,
|
|
&as->arcstat_mfu_size,
|
|
&as->arcstat_mfu_evictable_data,
|
|
&as->arcstat_mfu_evictable_metadata);
|
|
arc_kstat_update_state(arc_mfu_ghost,
|
|
&as->arcstat_mfu_ghost_size,
|
|
&as->arcstat_mfu_ghost_evictable_data,
|
|
&as->arcstat_mfu_ghost_evictable_metadata);
|
|
|
|
ARCSTAT(arcstat_size) = aggsum_value(&arc_size);
|
|
ARCSTAT(arcstat_meta_used) = aggsum_value(&arc_meta_used);
|
|
ARCSTAT(arcstat_data_size) = aggsum_value(&astat_data_size);
|
|
ARCSTAT(arcstat_metadata_size) =
|
|
aggsum_value(&astat_metadata_size);
|
|
ARCSTAT(arcstat_hdr_size) = aggsum_value(&astat_hdr_size);
|
|
ARCSTAT(arcstat_l2_hdr_size) = aggsum_value(&astat_l2_hdr_size);
|
|
ARCSTAT(arcstat_dbuf_size) = aggsum_value(&astat_dbuf_size);
|
|
#if defined(COMPAT_FREEBSD11)
|
|
ARCSTAT(arcstat_other_size) = aggsum_value(&astat_bonus_size) +
|
|
aggsum_value(&astat_dnode_size) +
|
|
aggsum_value(&astat_dbuf_size);
|
|
#endif
|
|
ARCSTAT(arcstat_dnode_size) = aggsum_value(&astat_dnode_size);
|
|
ARCSTAT(arcstat_bonus_size) = aggsum_value(&astat_bonus_size);
|
|
ARCSTAT(arcstat_abd_chunk_waste_size) =
|
|
aggsum_value(&astat_abd_chunk_waste_size);
|
|
|
|
as->arcstat_memory_all_bytes.value.ui64 =
|
|
arc_all_memory();
|
|
as->arcstat_memory_free_bytes.value.ui64 =
|
|
arc_free_memory();
|
|
as->arcstat_memory_available_bytes.value.i64 =
|
|
arc_available_memory();
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* This function *must* return indices evenly distributed between all
|
|
* sublists of the multilist. This is needed due to how the ARC eviction
|
|
* code is laid out; arc_evict_state() assumes ARC buffers are evenly
|
|
* distributed between all sublists and uses this assumption when
|
|
* deciding which sublist to evict from and how much to evict from it.
|
|
*/
|
|
static unsigned int
|
|
arc_state_multilist_index_func(multilist_t *ml, void *obj)
|
|
{
|
|
arc_buf_hdr_t *hdr = obj;
|
|
|
|
/*
|
|
* We rely on b_dva to generate evenly distributed index
|
|
* numbers using buf_hash below. So, as an added precaution,
|
|
* let's make sure we never add empty buffers to the arc lists.
|
|
*/
|
|
ASSERT(!HDR_EMPTY(hdr));
|
|
|
|
/*
|
|
* The assumption here, is the hash value for a given
|
|
* arc_buf_hdr_t will remain constant throughout its lifetime
|
|
* (i.e. its b_spa, b_dva, and b_birth fields don't change).
|
|
* Thus, we don't need to store the header's sublist index
|
|
* on insertion, as this index can be recalculated on removal.
|
|
*
|
|
* Also, the low order bits of the hash value are thought to be
|
|
* distributed evenly. Otherwise, in the case that the multilist
|
|
* has a power of two number of sublists, each sublists' usage
|
|
* would not be evenly distributed.
|
|
*/
|
|
return (buf_hash(hdr->b_spa, &hdr->b_dva, hdr->b_birth) %
|
|
multilist_get_num_sublists(ml));
|
|
}
|
|
|
|
#define WARN_IF_TUNING_IGNORED(tuning, value, do_warn) do { \
|
|
if ((do_warn) && (tuning) && ((tuning) != (value))) { \
|
|
cmn_err(CE_WARN, \
|
|
"ignoring tunable %s (using %llu instead)", \
|
|
(#tuning), (value)); \
|
|
} \
|
|
} while (0)
|
|
|
|
/*
|
|
* Called during module initialization and periodically thereafter to
|
|
* apply reasonable changes to the exposed performance tunings. Can also be
|
|
* called explicitly by param_set_arc_*() functions when ARC tunables are
|
|
* updated manually. Non-zero zfs_* values which differ from the currently set
|
|
* values will be applied.
|
|
*/
|
|
void
|
|
arc_tuning_update(boolean_t verbose)
|
|
{
|
|
uint64_t allmem = arc_all_memory();
|
|
unsigned long limit;
|
|
|
|
/* Valid range: 32M - <arc_c_max> */
|
|
if ((zfs_arc_min) && (zfs_arc_min != arc_c_min) &&
|
|
(zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT) &&
|
|
(zfs_arc_min <= arc_c_max)) {
|
|
arc_c_min = zfs_arc_min;
|
|
arc_c = MAX(arc_c, arc_c_min);
|
|
}
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_min, arc_c_min, verbose);
|
|
|
|
/* Valid range: 64M - <all physical memory> */
|
|
if ((zfs_arc_max) && (zfs_arc_max != arc_c_max) &&
|
|
(zfs_arc_max >= 64 << 20) && (zfs_arc_max < allmem) &&
|
|
(zfs_arc_max > arc_c_min)) {
|
|
arc_c_max = zfs_arc_max;
|
|
arc_c = MIN(arc_c, arc_c_max);
|
|
arc_p = (arc_c >> 1);
|
|
if (arc_meta_limit > arc_c_max)
|
|
arc_meta_limit = arc_c_max;
|
|
if (arc_dnode_size_limit > arc_meta_limit)
|
|
arc_dnode_size_limit = arc_meta_limit;
|
|
}
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_max, arc_c_max, verbose);
|
|
|
|
/* Valid range: 16M - <arc_c_max> */
|
|
if ((zfs_arc_meta_min) && (zfs_arc_meta_min != arc_meta_min) &&
|
|
(zfs_arc_meta_min >= 1ULL << SPA_MAXBLOCKSHIFT) &&
|
|
(zfs_arc_meta_min <= arc_c_max)) {
|
|
arc_meta_min = zfs_arc_meta_min;
|
|
if (arc_meta_limit < arc_meta_min)
|
|
arc_meta_limit = arc_meta_min;
|
|
if (arc_dnode_size_limit < arc_meta_min)
|
|
arc_dnode_size_limit = arc_meta_min;
|
|
}
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_meta_min, arc_meta_min, verbose);
|
|
|
|
/* Valid range: <arc_meta_min> - <arc_c_max> */
|
|
limit = zfs_arc_meta_limit ? zfs_arc_meta_limit :
|
|
MIN(zfs_arc_meta_limit_percent, 100) * arc_c_max / 100;
|
|
if ((limit != arc_meta_limit) &&
|
|
(limit >= arc_meta_min) &&
|
|
(limit <= arc_c_max))
|
|
arc_meta_limit = limit;
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_meta_limit, arc_meta_limit, verbose);
|
|
|
|
/* Valid range: <arc_meta_min> - <arc_meta_limit> */
|
|
limit = zfs_arc_dnode_limit ? zfs_arc_dnode_limit :
|
|
MIN(zfs_arc_dnode_limit_percent, 100) * arc_meta_limit / 100;
|
|
if ((limit != arc_dnode_size_limit) &&
|
|
(limit >= arc_meta_min) &&
|
|
(limit <= arc_meta_limit))
|
|
arc_dnode_size_limit = limit;
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_dnode_limit, arc_dnode_size_limit,
|
|
verbose);
|
|
|
|
/* Valid range: 1 - N */
|
|
if (zfs_arc_grow_retry)
|
|
arc_grow_retry = zfs_arc_grow_retry;
|
|
|
|
/* Valid range: 1 - N */
|
|
if (zfs_arc_shrink_shift) {
|
|
arc_shrink_shift = zfs_arc_shrink_shift;
|
|
arc_no_grow_shift = MIN(arc_no_grow_shift, arc_shrink_shift -1);
|
|
}
|
|
|
|
/* Valid range: 1 - N */
|
|
if (zfs_arc_p_min_shift)
|
|
arc_p_min_shift = zfs_arc_p_min_shift;
|
|
|
|
/* Valid range: 1 - N ms */
|
|
if (zfs_arc_min_prefetch_ms)
|
|
arc_min_prefetch_ms = zfs_arc_min_prefetch_ms;
|
|
|
|
/* Valid range: 1 - N ms */
|
|
if (zfs_arc_min_prescient_prefetch_ms) {
|
|
arc_min_prescient_prefetch_ms =
|
|
zfs_arc_min_prescient_prefetch_ms;
|
|
}
|
|
|
|
/* Valid range: 0 - 100 */
|
|
if ((zfs_arc_lotsfree_percent >= 0) &&
|
|
(zfs_arc_lotsfree_percent <= 100))
|
|
arc_lotsfree_percent = zfs_arc_lotsfree_percent;
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_lotsfree_percent, arc_lotsfree_percent,
|
|
verbose);
|
|
|
|
/* Valid range: 0 - <all physical memory> */
|
|
if ((zfs_arc_sys_free) && (zfs_arc_sys_free != arc_sys_free))
|
|
arc_sys_free = MIN(MAX(zfs_arc_sys_free, 0), allmem);
|
|
WARN_IF_TUNING_IGNORED(zfs_arc_sys_free, arc_sys_free, verbose);
|
|
}
|
|
|
|
static void
|
|
arc_state_init(void)
|
|
{
|
|
arc_anon = &ARC_anon;
|
|
arc_mru = &ARC_mru;
|
|
arc_mru_ghost = &ARC_mru_ghost;
|
|
arc_mfu = &ARC_mfu;
|
|
arc_mfu_ghost = &ARC_mfu_ghost;
|
|
arc_l2c_only = &ARC_l2c_only;
|
|
|
|
arc_mru->arcs_list[ARC_BUFC_METADATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mru->arcs_list[ARC_BUFC_DATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mru_ghost->arcs_list[ARC_BUFC_METADATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mru_ghost->arcs_list[ARC_BUFC_DATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mfu->arcs_list[ARC_BUFC_METADATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mfu->arcs_list[ARC_BUFC_DATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_mfu_ghost->arcs_list[ARC_BUFC_DATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_l2c_only->arcs_list[ARC_BUFC_METADATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
arc_l2c_only->arcs_list[ARC_BUFC_DATA] =
|
|
multilist_create(sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
arc_state_multilist_index_func);
|
|
|
|
zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]);
|
|
|
|
zfs_refcount_create(&arc_anon->arcs_size);
|
|
zfs_refcount_create(&arc_mru->arcs_size);
|
|
zfs_refcount_create(&arc_mru_ghost->arcs_size);
|
|
zfs_refcount_create(&arc_mfu->arcs_size);
|
|
zfs_refcount_create(&arc_mfu_ghost->arcs_size);
|
|
zfs_refcount_create(&arc_l2c_only->arcs_size);
|
|
|
|
aggsum_init(&arc_meta_used, 0);
|
|
aggsum_init(&arc_size, 0);
|
|
aggsum_init(&astat_data_size, 0);
|
|
aggsum_init(&astat_metadata_size, 0);
|
|
aggsum_init(&astat_hdr_size, 0);
|
|
aggsum_init(&astat_l2_hdr_size, 0);
|
|
aggsum_init(&astat_bonus_size, 0);
|
|
aggsum_init(&astat_dnode_size, 0);
|
|
aggsum_init(&astat_dbuf_size, 0);
|
|
aggsum_init(&astat_abd_chunk_waste_size, 0);
|
|
|
|
arc_anon->arcs_state = ARC_STATE_ANON;
|
|
arc_mru->arcs_state = ARC_STATE_MRU;
|
|
arc_mru_ghost->arcs_state = ARC_STATE_MRU_GHOST;
|
|
arc_mfu->arcs_state = ARC_STATE_MFU;
|
|
arc_mfu_ghost->arcs_state = ARC_STATE_MFU_GHOST;
|
|
arc_l2c_only->arcs_state = ARC_STATE_L2C_ONLY;
|
|
}
|
|
|
|
static void
|
|
arc_state_fini(void)
|
|
{
|
|
zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]);
|
|
zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]);
|
|
zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]);
|
|
|
|
zfs_refcount_destroy(&arc_anon->arcs_size);
|
|
zfs_refcount_destroy(&arc_mru->arcs_size);
|
|
zfs_refcount_destroy(&arc_mru_ghost->arcs_size);
|
|
zfs_refcount_destroy(&arc_mfu->arcs_size);
|
|
zfs_refcount_destroy(&arc_mfu_ghost->arcs_size);
|
|
zfs_refcount_destroy(&arc_l2c_only->arcs_size);
|
|
|
|
multilist_destroy(arc_mru->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(arc_mfu->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(arc_mru->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(arc_mru_ghost->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(arc_mfu->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(arc_l2c_only->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(arc_l2c_only->arcs_list[ARC_BUFC_DATA]);
|
|
|
|
aggsum_fini(&arc_meta_used);
|
|
aggsum_fini(&arc_size);
|
|
aggsum_fini(&astat_data_size);
|
|
aggsum_fini(&astat_metadata_size);
|
|
aggsum_fini(&astat_hdr_size);
|
|
aggsum_fini(&astat_l2_hdr_size);
|
|
aggsum_fini(&astat_bonus_size);
|
|
aggsum_fini(&astat_dnode_size);
|
|
aggsum_fini(&astat_dbuf_size);
|
|
aggsum_fini(&astat_abd_chunk_waste_size);
|
|
}
|
|
|
|
uint64_t
|
|
arc_target_bytes(void)
|
|
{
|
|
return (arc_c);
|
|
}
|
|
|
|
void
|
|
arc_init(void)
|
|
{
|
|
uint64_t percent, allmem = arc_all_memory();
|
|
mutex_init(&arc_evict_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
list_create(&arc_evict_waiters, sizeof (arc_evict_waiter_t),
|
|
offsetof(arc_evict_waiter_t, aew_node));
|
|
|
|
arc_min_prefetch_ms = 1000;
|
|
arc_min_prescient_prefetch_ms = 6000;
|
|
|
|
#if defined(_KERNEL)
|
|
arc_lowmem_init();
|
|
#endif
|
|
|
|
/* Set min cache to 1/32 of all memory, or 32MB, whichever is more. */
|
|
arc_c_min = MAX(allmem / 32, 2ULL << SPA_MAXBLOCKSHIFT);
|
|
|
|
/* How to set default max varies by platform. */
|
|
arc_c_max = arc_default_max(arc_c_min, allmem);
|
|
|
|
#ifndef _KERNEL
|
|
/*
|
|
* In userland, there's only the memory pressure that we artificially
|
|
* create (see arc_available_memory()). Don't let arc_c get too
|
|
* small, because it can cause transactions to be larger than
|
|
* arc_c, causing arc_tempreserve_space() to fail.
|
|
*/
|
|
arc_c_min = MAX(arc_c_max / 2, 2ULL << SPA_MAXBLOCKSHIFT);
|
|
#endif
|
|
|
|
arc_c = arc_c_min;
|
|
arc_p = (arc_c >> 1);
|
|
|
|
/* Set min to 1/2 of arc_c_min */
|
|
arc_meta_min = 1ULL << SPA_MAXBLOCKSHIFT;
|
|
/* Initialize maximum observed usage to zero */
|
|
arc_meta_max = 0;
|
|
/*
|
|
* Set arc_meta_limit to a percent of arc_c_max with a floor of
|
|
* arc_meta_min, and a ceiling of arc_c_max.
|
|
*/
|
|
percent = MIN(zfs_arc_meta_limit_percent, 100);
|
|
arc_meta_limit = MAX(arc_meta_min, (percent * arc_c_max) / 100);
|
|
percent = MIN(zfs_arc_dnode_limit_percent, 100);
|
|
arc_dnode_size_limit = (percent * arc_meta_limit) / 100;
|
|
|
|
/* Apply user specified tunings */
|
|
arc_tuning_update(B_TRUE);
|
|
|
|
/* if kmem_flags are set, lets try to use less memory */
|
|
if (kmem_debugging())
|
|
arc_c = arc_c / 2;
|
|
if (arc_c < arc_c_min)
|
|
arc_c = arc_c_min;
|
|
|
|
arc_state_init();
|
|
|
|
buf_init();
|
|
|
|
list_create(&arc_prune_list, sizeof (arc_prune_t),
|
|
offsetof(arc_prune_t, p_node));
|
|
mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
|
|
arc_prune_taskq = taskq_create("arc_prune", boot_ncpus, defclsyspri,
|
|
boot_ncpus, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
|
|
|
|
arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED,
|
|
sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL);
|
|
|
|
if (arc_ksp != NULL) {
|
|
arc_ksp->ks_data = &arc_stats;
|
|
arc_ksp->ks_update = arc_kstat_update;
|
|
kstat_install(arc_ksp);
|
|
}
|
|
|
|
arc_evict_zthr = zthr_create_timer("arc_evict",
|
|
arc_evict_cb_check, arc_evict_cb, NULL, SEC2NSEC(1));
|
|
arc_reap_zthr = zthr_create_timer("arc_reap",
|
|
arc_reap_cb_check, arc_reap_cb, NULL, SEC2NSEC(1));
|
|
|
|
arc_warm = B_FALSE;
|
|
|
|
/*
|
|
* Calculate maximum amount of dirty data per pool.
|
|
*
|
|
* If it has been set by a module parameter, take that.
|
|
* Otherwise, use a percentage of physical memory defined by
|
|
* zfs_dirty_data_max_percent (default 10%) with a cap at
|
|
* zfs_dirty_data_max_max (default 4G or 25% of physical memory).
|
|
*/
|
|
#ifdef __LP64__
|
|
if (zfs_dirty_data_max_max == 0)
|
|
zfs_dirty_data_max_max = MIN(4ULL * 1024 * 1024 * 1024,
|
|
allmem * zfs_dirty_data_max_max_percent / 100);
|
|
#else
|
|
if (zfs_dirty_data_max_max == 0)
|
|
zfs_dirty_data_max_max = MIN(1ULL * 1024 * 1024 * 1024,
|
|
allmem * zfs_dirty_data_max_max_percent / 100);
|
|
#endif
|
|
|
|
if (zfs_dirty_data_max == 0) {
|
|
zfs_dirty_data_max = allmem *
|
|
zfs_dirty_data_max_percent / 100;
|
|
zfs_dirty_data_max = MIN(zfs_dirty_data_max,
|
|
zfs_dirty_data_max_max);
|
|
}
|
|
}
|
|
|
|
void
|
|
arc_fini(void)
|
|
{
|
|
arc_prune_t *p;
|
|
|
|
#ifdef _KERNEL
|
|
arc_lowmem_fini();
|
|
#endif /* _KERNEL */
|
|
|
|
/* Use B_TRUE to ensure *all* buffers are evicted */
|
|
arc_flush(NULL, B_TRUE);
|
|
|
|
if (arc_ksp != NULL) {
|
|
kstat_delete(arc_ksp);
|
|
arc_ksp = NULL;
|
|
}
|
|
|
|
taskq_wait(arc_prune_taskq);
|
|
taskq_destroy(arc_prune_taskq);
|
|
|
|
mutex_enter(&arc_prune_mtx);
|
|
while ((p = list_head(&arc_prune_list)) != NULL) {
|
|
list_remove(&arc_prune_list, p);
|
|
zfs_refcount_remove(&p->p_refcnt, &arc_prune_list);
|
|
zfs_refcount_destroy(&p->p_refcnt);
|
|
kmem_free(p, sizeof (*p));
|
|
}
|
|
mutex_exit(&arc_prune_mtx);
|
|
|
|
list_destroy(&arc_prune_list);
|
|
mutex_destroy(&arc_prune_mtx);
|
|
|
|
(void) zthr_cancel(arc_evict_zthr);
|
|
(void) zthr_cancel(arc_reap_zthr);
|
|
|
|
mutex_destroy(&arc_evict_lock);
|
|
list_destroy(&arc_evict_waiters);
|
|
|
|
/*
|
|
* Free any buffers that were tagged for destruction. This needs
|
|
* to occur before arc_state_fini() runs and destroys the aggsum
|
|
* values which are updated when freeing scatter ABDs.
|
|
*/
|
|
l2arc_do_free_on_write();
|
|
|
|
/*
|
|
* buf_fini() must proceed arc_state_fini() because buf_fin() may
|
|
* trigger the release of kmem magazines, which can callback to
|
|
* arc_space_return() which accesses aggsums freed in act_state_fini().
|
|
*/
|
|
buf_fini();
|
|
arc_state_fini();
|
|
|
|
/*
|
|
* We destroy the zthrs after all the ARC state has been
|
|
* torn down to avoid the case of them receiving any
|
|
* wakeup() signals after they are destroyed.
|
|
*/
|
|
zthr_destroy(arc_evict_zthr);
|
|
zthr_destroy(arc_reap_zthr);
|
|
|
|
ASSERT0(arc_loaned_bytes);
|
|
}
|
|
|
|
/*
|
|
* Level 2 ARC
|
|
*
|
|
* The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk.
|
|
* It uses dedicated storage devices to hold cached data, which are populated
|
|
* using large infrequent writes. The main role of this cache is to boost
|
|
* the performance of random read workloads. The intended L2ARC devices
|
|
* include short-stroked disks, solid state disks, and other media with
|
|
* substantially faster read latency than disk.
|
|
*
|
|
* +-----------------------+
|
|
* | ARC |
|
|
* +-----------------------+
|
|
* | ^ ^
|
|
* | | |
|
|
* l2arc_feed_thread() arc_read()
|
|
* | | |
|
|
* | l2arc read |
|
|
* V | |
|
|
* +---------------+ |
|
|
* | L2ARC | |
|
|
* +---------------+ |
|
|
* | ^ |
|
|
* l2arc_write() | |
|
|
* | | |
|
|
* V | |
|
|
* +-------+ +-------+
|
|
* | vdev | | vdev |
|
|
* | cache | | cache |
|
|
* +-------+ +-------+
|
|
* +=========+ .-----.
|
|
* : L2ARC : |-_____-|
|
|
* : devices : | Disks |
|
|
* +=========+ `-_____-'
|
|
*
|
|
* Read requests are satisfied from the following sources, in order:
|
|
*
|
|
* 1) ARC
|
|
* 2) vdev cache of L2ARC devices
|
|
* 3) L2ARC devices
|
|
* 4) vdev cache of disks
|
|
* 5) disks
|
|
*
|
|
* Some L2ARC device types exhibit extremely slow write performance.
|
|
* To accommodate for this there are some significant differences between
|
|
* the L2ARC and traditional cache design:
|
|
*
|
|
* 1. There is no eviction path from the ARC to the L2ARC. Evictions from
|
|
* the ARC behave as usual, freeing buffers and placing headers on ghost
|
|
* lists. The ARC does not send buffers to the L2ARC during eviction as
|
|
* this would add inflated write latencies for all ARC memory pressure.
|
|
*
|
|
* 2. The L2ARC attempts to cache data from the ARC before it is evicted.
|
|
* It does this by periodically scanning buffers from the eviction-end of
|
|
* the MFU and MRU ARC lists, copying them to the L2ARC devices if they are
|
|
* not already there. It scans until a headroom of buffers is satisfied,
|
|
* which itself is a buffer for ARC eviction. If a compressible buffer is
|
|
* found during scanning and selected for writing to an L2ARC device, we
|
|
* temporarily boost scanning headroom during the next scan cycle to make
|
|
* sure we adapt to compression effects (which might significantly reduce
|
|
* the data volume we write to L2ARC). The thread that does this is
|
|
* l2arc_feed_thread(), illustrated below; example sizes are included to
|
|
* provide a better sense of ratio than this diagram:
|
|
*
|
|
* head --> tail
|
|
* +---------------------+----------+
|
|
* ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC
|
|
* +---------------------+----------+ | o L2ARC eligible
|
|
* ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer
|
|
* +---------------------+----------+ |
|
|
* 15.9 Gbytes ^ 32 Mbytes |
|
|
* headroom |
|
|
* l2arc_feed_thread()
|
|
* |
|
|
* l2arc write hand <--[oooo]--'
|
|
* | 8 Mbyte
|
|
* | write max
|
|
* V
|
|
* +==============================+
|
|
* L2ARC dev |####|#|###|###| |####| ... |
|
|
* +==============================+
|
|
* 32 Gbytes
|
|
*
|
|
* 3. If an ARC buffer is copied to the L2ARC but then hit instead of
|
|
* evicted, then the L2ARC has cached a buffer much sooner than it probably
|
|
* needed to, potentially wasting L2ARC device bandwidth and storage. It is
|
|
* safe to say that this is an uncommon case, since buffers at the end of
|
|
* the ARC lists have moved there due to inactivity.
|
|
*
|
|
* 4. If the ARC evicts faster than the L2ARC can maintain a headroom,
|
|
* then the L2ARC simply misses copying some buffers. This serves as a
|
|
* pressure valve to prevent heavy read workloads from both stalling the ARC
|
|
* with waits and clogging the L2ARC with writes. This also helps prevent
|
|
* the potential for the L2ARC to churn if it attempts to cache content too
|
|
* quickly, such as during backups of the entire pool.
|
|
*
|
|
* 5. After system boot and before the ARC has filled main memory, there are
|
|
* no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru
|
|
* lists can remain mostly static. Instead of searching from tail of these
|
|
* lists as pictured, the l2arc_feed_thread() will search from the list heads
|
|
* for eligible buffers, greatly increasing its chance of finding them.
|
|
*
|
|
* The L2ARC device write speed is also boosted during this time so that
|
|
* the L2ARC warms up faster. Since there have been no ARC evictions yet,
|
|
* there are no L2ARC reads, and no fear of degrading read performance
|
|
* through increased writes.
|
|
*
|
|
* 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that
|
|
* the vdev queue can aggregate them into larger and fewer writes. Each
|
|
* device is written to in a rotor fashion, sweeping writes through
|
|
* available space then repeating.
|
|
*
|
|
* 7. The L2ARC does not store dirty content. It never needs to flush
|
|
* write buffers back to disk based storage.
|
|
*
|
|
* 8. If an ARC buffer is written (and dirtied) which also exists in the
|
|
* L2ARC, the now stale L2ARC buffer is immediately dropped.
|
|
*
|
|
* The performance of the L2ARC can be tweaked by a number of tunables, which
|
|
* may be necessary for different workloads:
|
|
*
|
|
* l2arc_write_max max write bytes per interval
|
|
* l2arc_write_boost extra write bytes during device warmup
|
|
* l2arc_noprefetch skip caching prefetched buffers
|
|
* l2arc_headroom number of max device writes to precache
|
|
* l2arc_headroom_boost when we find compressed buffers during ARC
|
|
* scanning, we multiply headroom by this
|
|
* percentage factor for the next scan cycle,
|
|
* since more compressed buffers are likely to
|
|
* be present
|
|
* l2arc_feed_secs seconds between L2ARC writing
|
|
*
|
|
* Tunables may be removed or added as future performance improvements are
|
|
* integrated, and also may become zpool properties.
|
|
*
|
|
* There are three key functions that control how the L2ARC warms up:
|
|
*
|
|
* l2arc_write_eligible() check if a buffer is eligible to cache
|
|
* l2arc_write_size() calculate how much to write
|
|
* l2arc_write_interval() calculate sleep delay between writes
|
|
*
|
|
* These three functions determine what to write, how much, and how quickly
|
|
* to send writes.
|
|
*
|
|
* L2ARC persistence:
|
|
*
|
|
* When writing buffers to L2ARC, we periodically add some metadata to
|
|
* make sure we can pick them up after reboot, thus dramatically reducing
|
|
* the impact that any downtime has on the performance of storage systems
|
|
* with large caches.
|
|
*
|
|
* The implementation works fairly simply by integrating the following two
|
|
* modifications:
|
|
*
|
|
* *) When writing to the L2ARC, we occasionally write a "l2arc log block",
|
|
* which is an additional piece of metadata which describes what's been
|
|
* written. This allows us to rebuild the arc_buf_hdr_t structures of the
|
|
* main ARC buffers. There are 2 linked-lists of log blocks headed by
|
|
* dh_start_lbps[2]. We alternate which chain we append to, so they are
|
|
* time-wise and offset-wise interleaved, but that is an optimization rather
|
|
* than for correctness. The log block also includes a pointer to the
|
|
* previous block in its chain.
|
|
*
|
|
* *) We reserve SPA_MINBLOCKSIZE of space at the start of each L2ARC device
|
|
* for our header bookkeeping purposes. This contains a device header,
|
|
* which contains our top-level reference structures. We update it each
|
|
* time we write a new log block, so that we're able to locate it in the
|
|
* L2ARC device. If this write results in an inconsistent device header
|
|
* (e.g. due to power failure), we detect this by verifying the header's
|
|
* checksum and simply fail to reconstruct the L2ARC after reboot.
|
|
*
|
|
* Implementation diagram:
|
|
*
|
|
* +=== L2ARC device (not to scale) ======================================+
|
|
* | ___two newest log block pointers__.__________ |
|
|
* | / \dh_start_lbps[1] |
|
|
* | / \ \dh_start_lbps[0]|
|
|
* |.___/__. V V |
|
|
* ||L2 dev|....|lb |bufs |lb |bufs |lb |bufs |lb |bufs |lb |---(empty)---|
|
|
* || hdr| ^ /^ /^ / / |
|
|
* |+------+ ...--\-------/ \-----/--\------/ / |
|
|
* | \--------------/ \--------------/ |
|
|
* +======================================================================+
|
|
*
|
|
* As can be seen on the diagram, rather than using a simple linked list,
|
|
* we use a pair of linked lists with alternating elements. This is a
|
|
* performance enhancement due to the fact that we only find out the
|
|
* address of the next log block access once the current block has been
|
|
* completely read in. Obviously, this hurts performance, because we'd be
|
|
* keeping the device's I/O queue at only a 1 operation deep, thus
|
|
* incurring a large amount of I/O round-trip latency. Having two lists
|
|
* allows us to fetch two log blocks ahead of where we are currently
|
|
* rebuilding L2ARC buffers.
|
|
*
|
|
* On-device data structures:
|
|
*
|
|
* L2ARC device header: l2arc_dev_hdr_phys_t
|
|
* L2ARC log block: l2arc_log_blk_phys_t
|
|
*
|
|
* L2ARC reconstruction:
|
|
*
|
|
* When writing data, we simply write in the standard rotary fashion,
|
|
* evicting buffers as we go and simply writing new data over them (writing
|
|
* a new log block every now and then). This obviously means that once we
|
|
* loop around the end of the device, we will start cutting into an already
|
|
* committed log block (and its referenced data buffers), like so:
|
|
*
|
|
* current write head__ __old tail
|
|
* \ /
|
|
* V V
|
|
* <--|bufs |lb |bufs |lb | |bufs |lb |bufs |lb |-->
|
|
* ^ ^^^^^^^^^___________________________________
|
|
* | \
|
|
* <<nextwrite>> may overwrite this blk and/or its bufs --'
|
|
*
|
|
* When importing the pool, we detect this situation and use it to stop
|
|
* our scanning process (see l2arc_rebuild).
|
|
*
|
|
* There is one significant caveat to consider when rebuilding ARC contents
|
|
* from an L2ARC device: what about invalidated buffers? Given the above
|
|
* construction, we cannot update blocks which we've already written to amend
|
|
* them to remove buffers which were invalidated. Thus, during reconstruction,
|
|
* we might be populating the cache with buffers for data that's not on the
|
|
* main pool anymore, or may have been overwritten!
|
|
*
|
|
* As it turns out, this isn't a problem. Every arc_read request includes
|
|
* both the DVA and, crucially, the birth TXG of the BP the caller is
|
|
* looking for. So even if the cache were populated by completely rotten
|
|
* blocks for data that had been long deleted and/or overwritten, we'll
|
|
* never actually return bad data from the cache, since the DVA with the
|
|
* birth TXG uniquely identify a block in space and time - once created,
|
|
* a block is immutable on disk. The worst thing we have done is wasted
|
|
* some time and memory at l2arc rebuild to reconstruct outdated ARC
|
|
* entries that will get dropped from the l2arc as it is being updated
|
|
* with new blocks.
|
|
*
|
|
* L2ARC buffers that have been evicted by l2arc_evict() ahead of the write
|
|
* hand are not restored. This is done by saving the offset (in bytes)
|
|
* l2arc_evict() has evicted to in the L2ARC device header and taking it
|
|
* into account when restoring buffers.
|
|
*/
|
|
|
|
static boolean_t
|
|
l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *hdr)
|
|
{
|
|
/*
|
|
* A buffer is *not* eligible for the L2ARC if it:
|
|
* 1. belongs to a different spa.
|
|
* 2. is already cached on the L2ARC.
|
|
* 3. has an I/O in progress (it may be an incomplete read).
|
|
* 4. is flagged not eligible (zfs property).
|
|
*/
|
|
if (hdr->b_spa != spa_guid || HDR_HAS_L2HDR(hdr) ||
|
|
HDR_IO_IN_PROGRESS(hdr) || !HDR_L2CACHE(hdr))
|
|
return (B_FALSE);
|
|
|
|
return (B_TRUE);
|
|
}
|
|
|
|
static uint64_t
|
|
l2arc_write_size(l2arc_dev_t *dev)
|
|
{
|
|
uint64_t size, dev_size, tsize;
|
|
|
|
/*
|
|
* Make sure our globals have meaningful values in case the user
|
|
* altered them.
|
|
*/
|
|
size = l2arc_write_max;
|
|
if (size == 0) {
|
|
cmn_err(CE_NOTE, "Bad value for l2arc_write_max, value must "
|
|
"be greater than zero, resetting it to the default (%d)",
|
|
L2ARC_WRITE_SIZE);
|
|
size = l2arc_write_max = L2ARC_WRITE_SIZE;
|
|
}
|
|
|
|
if (arc_warm == B_FALSE)
|
|
size += l2arc_write_boost;
|
|
|
|
/*
|
|
* Make sure the write size does not exceed the size of the cache
|
|
* device. This is important in l2arc_evict(), otherwise infinite
|
|
* iteration can occur.
|
|
*/
|
|
dev_size = dev->l2ad_end - dev->l2ad_start;
|
|
tsize = size + l2arc_log_blk_overhead(size, dev);
|
|
if (dev->l2ad_vdev->vdev_has_trim && l2arc_trim_ahead > 0)
|
|
tsize += MAX(64 * 1024 * 1024,
|
|
(tsize * l2arc_trim_ahead) / 100);
|
|
|
|
if (tsize >= dev_size) {
|
|
cmn_err(CE_NOTE, "l2arc_write_max or l2arc_write_boost "
|
|
"plus the overhead of log blocks (persistent L2ARC, "
|
|
"%llu bytes) exceeds the size of the cache device "
|
|
"(guid %llu), resetting them to the default (%d)",
|
|
l2arc_log_blk_overhead(size, dev),
|
|
dev->l2ad_vdev->vdev_guid, L2ARC_WRITE_SIZE);
|
|
size = l2arc_write_max = l2arc_write_boost = L2ARC_WRITE_SIZE;
|
|
|
|
if (arc_warm == B_FALSE)
|
|
size += l2arc_write_boost;
|
|
}
|
|
|
|
return (size);
|
|
|
|
}
|
|
|
|
static clock_t
|
|
l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote)
|
|
{
|
|
clock_t interval, next, now;
|
|
|
|
/*
|
|
* If the ARC lists are busy, increase our write rate; if the
|
|
* lists are stale, idle back. This is achieved by checking
|
|
* how much we previously wrote - if it was more than half of
|
|
* what we wanted, schedule the next write much sooner.
|
|
*/
|
|
if (l2arc_feed_again && wrote > (wanted / 2))
|
|
interval = (hz * l2arc_feed_min_ms) / 1000;
|
|
else
|
|
interval = hz * l2arc_feed_secs;
|
|
|
|
now = ddi_get_lbolt();
|
|
next = MAX(now, MIN(now + interval, began + interval));
|
|
|
|
return (next);
|
|
}
|
|
|
|
/*
|
|
* Cycle through L2ARC devices. This is how L2ARC load balances.
|
|
* If a device is returned, this also returns holding the spa config lock.
|
|
*/
|
|
static l2arc_dev_t *
|
|
l2arc_dev_get_next(void)
|
|
{
|
|
l2arc_dev_t *first, *next = NULL;
|
|
|
|
/*
|
|
* Lock out the removal of spas (spa_namespace_lock), then removal
|
|
* of cache devices (l2arc_dev_mtx). Once a device has been selected,
|
|
* both locks will be dropped and a spa config lock held instead.
|
|
*/
|
|
mutex_enter(&spa_namespace_lock);
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
|
|
/* if there are no vdevs, there is nothing to do */
|
|
if (l2arc_ndev == 0)
|
|
goto out;
|
|
|
|
first = NULL;
|
|
next = l2arc_dev_last;
|
|
do {
|
|
/* loop around the list looking for a non-faulted vdev */
|
|
if (next == NULL) {
|
|
next = list_head(l2arc_dev_list);
|
|
} else {
|
|
next = list_next(l2arc_dev_list, next);
|
|
if (next == NULL)
|
|
next = list_head(l2arc_dev_list);
|
|
}
|
|
|
|
/* if we have come back to the start, bail out */
|
|
if (first == NULL)
|
|
first = next;
|
|
else if (next == first)
|
|
break;
|
|
|
|
} while (vdev_is_dead(next->l2ad_vdev) || next->l2ad_rebuild ||
|
|
next->l2ad_trim_all);
|
|
|
|
/* if we were unable to find any usable vdevs, return NULL */
|
|
if (vdev_is_dead(next->l2ad_vdev) || next->l2ad_rebuild ||
|
|
next->l2ad_trim_all)
|
|
next = NULL;
|
|
|
|
l2arc_dev_last = next;
|
|
|
|
out:
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
/*
|
|
* Grab the config lock to prevent the 'next' device from being
|
|
* removed while we are writing to it.
|
|
*/
|
|
if (next != NULL)
|
|
spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER);
|
|
mutex_exit(&spa_namespace_lock);
|
|
|
|
return (next);
|
|
}
|
|
|
|
/*
|
|
* Free buffers that were tagged for destruction.
|
|
*/
|
|
static void
|
|
l2arc_do_free_on_write(void)
|
|
{
|
|
list_t *buflist;
|
|
l2arc_data_free_t *df, *df_prev;
|
|
|
|
mutex_enter(&l2arc_free_on_write_mtx);
|
|
buflist = l2arc_free_on_write;
|
|
|
|
for (df = list_tail(buflist); df; df = df_prev) {
|
|
df_prev = list_prev(buflist, df);
|
|
ASSERT3P(df->l2df_abd, !=, NULL);
|
|
abd_free(df->l2df_abd);
|
|
list_remove(buflist, df);
|
|
kmem_free(df, sizeof (l2arc_data_free_t));
|
|
}
|
|
|
|
mutex_exit(&l2arc_free_on_write_mtx);
|
|
}
|
|
|
|
/*
|
|
* A write to a cache device has completed. Update all headers to allow
|
|
* reads from these buffers to begin.
|
|
*/
|
|
static void
|
|
l2arc_write_done(zio_t *zio)
|
|
{
|
|
l2arc_write_callback_t *cb;
|
|
l2arc_lb_abd_buf_t *abd_buf;
|
|
l2arc_lb_ptr_buf_t *lb_ptr_buf;
|
|
l2arc_dev_t *dev;
|
|
l2arc_dev_hdr_phys_t *l2dhdr;
|
|
list_t *buflist;
|
|
arc_buf_hdr_t *head, *hdr, *hdr_prev;
|
|
kmutex_t *hash_lock;
|
|
int64_t bytes_dropped = 0;
|
|
|
|
cb = zio->io_private;
|
|
ASSERT3P(cb, !=, NULL);
|
|
dev = cb->l2wcb_dev;
|
|
l2dhdr = dev->l2ad_dev_hdr;
|
|
ASSERT3P(dev, !=, NULL);
|
|
head = cb->l2wcb_head;
|
|
ASSERT3P(head, !=, NULL);
|
|
buflist = &dev->l2ad_buflist;
|
|
ASSERT3P(buflist, !=, NULL);
|
|
DTRACE_PROBE2(l2arc__iodone, zio_t *, zio,
|
|
l2arc_write_callback_t *, cb);
|
|
|
|
if (zio->io_error != 0)
|
|
ARCSTAT_BUMP(arcstat_l2_writes_error);
|
|
|
|
/*
|
|
* All writes completed, or an error was hit.
|
|
*/
|
|
top:
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
for (hdr = list_prev(buflist, head); hdr; hdr = hdr_prev) {
|
|
hdr_prev = list_prev(buflist, hdr);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We cannot use mutex_enter or else we can deadlock
|
|
* with l2arc_write_buffers (due to swapping the order
|
|
* the hash lock and l2ad_mtx are taken).
|
|
*/
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Missed the hash lock. We must retry so we
|
|
* don't leave the ARC_FLAG_L2_WRITING bit set.
|
|
*/
|
|
ARCSTAT_BUMP(arcstat_l2_writes_lock_retry);
|
|
|
|
/*
|
|
* We don't want to rescan the headers we've
|
|
* already marked as having been written out, so
|
|
* we reinsert the head node so we can pick up
|
|
* where we left off.
|
|
*/
|
|
list_remove(buflist, head);
|
|
list_insert_after(buflist, hdr, head);
|
|
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We wait for the hash lock to become available
|
|
* to try and prevent busy waiting, and increase
|
|
* the chance we'll be able to acquire the lock
|
|
* the next time around.
|
|
*/
|
|
mutex_enter(hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
|
|
/*
|
|
* We could not have been moved into the arc_l2c_only
|
|
* state while in-flight due to our ARC_FLAG_L2_WRITING
|
|
* bit being set. Let's just ensure that's being enforced.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
/*
|
|
* Skipped - drop L2ARC entry and mark the header as no
|
|
* longer L2 eligibile.
|
|
*/
|
|
if (zio->io_error != 0) {
|
|
/*
|
|
* Error - drop L2ARC entry.
|
|
*/
|
|
list_remove(buflist, hdr);
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR);
|
|
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
ARCSTAT_INCR(arcstat_l2_psize, -psize);
|
|
ARCSTAT_INCR(arcstat_l2_lsize, -HDR_GET_LSIZE(hdr));
|
|
|
|
bytes_dropped +=
|
|
vdev_psize_to_asize(dev->l2ad_vdev, psize);
|
|
(void) zfs_refcount_remove_many(&dev->l2ad_alloc,
|
|
arc_hdr_size(hdr), hdr);
|
|
}
|
|
|
|
/*
|
|
* Allow ARC to begin reads and ghost list evictions to
|
|
* this L2ARC entry.
|
|
*/
|
|
arc_hdr_clear_flags(hdr, ARC_FLAG_L2_WRITING);
|
|
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
/*
|
|
* Free the allocated abd buffers for writing the log blocks.
|
|
* If the zio failed reclaim the allocated space and remove the
|
|
* pointers to these log blocks from the log block pointer list
|
|
* of the L2ARC device.
|
|
*/
|
|
while ((abd_buf = list_remove_tail(&cb->l2wcb_abd_list)) != NULL) {
|
|
abd_free(abd_buf->abd);
|
|
zio_buf_free(abd_buf, sizeof (*abd_buf));
|
|
if (zio->io_error != 0) {
|
|
lb_ptr_buf = list_remove_head(&dev->l2ad_lbptr_list);
|
|
/*
|
|
* L2BLK_GET_PSIZE returns aligned size for log
|
|
* blocks.
|
|
*/
|
|
uint64_t asize =
|
|
L2BLK_GET_PSIZE((lb_ptr_buf->lb_ptr)->lbp_prop);
|
|
bytes_dropped += asize;
|
|
ARCSTAT_INCR(arcstat_l2_log_blk_asize, -asize);
|
|
ARCSTAT_BUMPDOWN(arcstat_l2_log_blk_count);
|
|
zfs_refcount_remove_many(&dev->l2ad_lb_asize, asize,
|
|
lb_ptr_buf);
|
|
zfs_refcount_remove(&dev->l2ad_lb_count, lb_ptr_buf);
|
|
kmem_free(lb_ptr_buf->lb_ptr,
|
|
sizeof (l2arc_log_blkptr_t));
|
|
kmem_free(lb_ptr_buf, sizeof (l2arc_lb_ptr_buf_t));
|
|
}
|
|
}
|
|
list_destroy(&cb->l2wcb_abd_list);
|
|
|
|
if (zio->io_error != 0) {
|
|
/*
|
|
* Restore the lbps array in the header to its previous state.
|
|
* If the list of log block pointers is empty, zero out the
|
|
* log block pointers in the device header.
|
|
*/
|
|
lb_ptr_buf = list_head(&dev->l2ad_lbptr_list);
|
|
for (int i = 0; i < 2; i++) {
|
|
if (lb_ptr_buf == NULL) {
|
|
/*
|
|
* If the list is empty zero out the device
|
|
* header. Otherwise zero out the second log
|
|
* block pointer in the header.
|
|
*/
|
|
if (i == 0) {
|
|
bzero(l2dhdr, dev->l2ad_dev_hdr_asize);
|
|
} else {
|
|
bzero(&l2dhdr->dh_start_lbps[i],
|
|
sizeof (l2arc_log_blkptr_t));
|
|
}
|
|
break;
|
|
}
|
|
bcopy(lb_ptr_buf->lb_ptr, &l2dhdr->dh_start_lbps[i],
|
|
sizeof (l2arc_log_blkptr_t));
|
|
lb_ptr_buf = list_next(&dev->l2ad_lbptr_list,
|
|
lb_ptr_buf);
|
|
}
|
|
}
|
|
|
|
atomic_inc_64(&l2arc_writes_done);
|
|
list_remove(buflist, head);
|
|
ASSERT(!HDR_HAS_L1HDR(head));
|
|
kmem_cache_free(hdr_l2only_cache, head);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
ASSERT(dev->l2ad_vdev != NULL);
|
|
vdev_space_update(dev->l2ad_vdev, -bytes_dropped, 0, 0);
|
|
|
|
l2arc_do_free_on_write();
|
|
|
|
kmem_free(cb, sizeof (l2arc_write_callback_t));
|
|
}
|
|
|
|
static int
|
|
l2arc_untransform(zio_t *zio, l2arc_read_callback_t *cb)
|
|
{
|
|
int ret;
|
|
spa_t *spa = zio->io_spa;
|
|
arc_buf_hdr_t *hdr = cb->l2rcb_hdr;
|
|
blkptr_t *bp = zio->io_bp;
|
|
uint8_t salt[ZIO_DATA_SALT_LEN];
|
|
uint8_t iv[ZIO_DATA_IV_LEN];
|
|
uint8_t mac[ZIO_DATA_MAC_LEN];
|
|
boolean_t no_crypt = B_FALSE;
|
|
|
|
/*
|
|
* ZIL data is never be written to the L2ARC, so we don't need
|
|
* special handling for its unique MAC storage.
|
|
*/
|
|
ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG);
|
|
ASSERT(MUTEX_HELD(HDR_LOCK(hdr)));
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
|
|
/*
|
|
* If the data was encrypted, decrypt it now. Note that
|
|
* we must check the bp here and not the hdr, since the
|
|
* hdr does not have its encryption parameters updated
|
|
* until arc_read_done().
|
|
*/
|
|
if (BP_IS_ENCRYPTED(bp)) {
|
|
abd_t *eabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr,
|
|
B_TRUE);
|
|
|
|
zio_crypt_decode_params_bp(bp, salt, iv);
|
|
zio_crypt_decode_mac_bp(bp, mac);
|
|
|
|
ret = spa_do_crypt_abd(B_FALSE, spa, &cb->l2rcb_zb,
|
|
BP_GET_TYPE(bp), BP_GET_DEDUP(bp), BP_SHOULD_BYTESWAP(bp),
|
|
salt, iv, mac, HDR_GET_PSIZE(hdr), eabd,
|
|
hdr->b_l1hdr.b_pabd, &no_crypt);
|
|
if (ret != 0) {
|
|
arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr);
|
|
goto error;
|
|
}
|
|
|
|
/*
|
|
* If we actually performed decryption, replace b_pabd
|
|
* with the decrypted data. Otherwise we can just throw
|
|
* our decryption buffer away.
|
|
*/
|
|
if (!no_crypt) {
|
|
arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd,
|
|
arc_hdr_size(hdr), hdr);
|
|
hdr->b_l1hdr.b_pabd = eabd;
|
|
zio->io_abd = eabd;
|
|
} else {
|
|
arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the L2ARC block was compressed, but ARC compression
|
|
* is disabled we decompress the data into a new buffer and
|
|
* replace the existing data.
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
|
|
!HDR_COMPRESSION_ENABLED(hdr)) {
|
|
abd_t *cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr,
|
|
B_TRUE);
|
|
void *tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr));
|
|
|
|
ret = zio_decompress_data(HDR_GET_COMPRESS(hdr),
|
|
hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr),
|
|
HDR_GET_LSIZE(hdr), &hdr->b_complevel);
|
|
if (ret != 0) {
|
|
abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr));
|
|
arc_free_data_abd(hdr, cabd, arc_hdr_size(hdr), hdr);
|
|
goto error;
|
|
}
|
|
|
|
abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr));
|
|
arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd,
|
|
arc_hdr_size(hdr), hdr);
|
|
hdr->b_l1hdr.b_pabd = cabd;
|
|
zio->io_abd = cabd;
|
|
zio->io_size = HDR_GET_LSIZE(hdr);
|
|
}
|
|
|
|
return (0);
|
|
|
|
error:
|
|
return (ret);
|
|
}
|
|
|
|
|
|
/*
|
|
* A read to a cache device completed. Validate buffer contents before
|
|
* handing over to the regular ARC routines.
|
|
*/
|
|
static void
|
|
l2arc_read_done(zio_t *zio)
|
|
{
|
|
int tfm_error = 0;
|
|
l2arc_read_callback_t *cb = zio->io_private;
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
boolean_t valid_cksum;
|
|
boolean_t using_rdata = (BP_IS_ENCRYPTED(&cb->l2rcb_bp) &&
|
|
(cb->l2rcb_flags & ZIO_FLAG_RAW_ENCRYPT));
|
|
|
|
ASSERT3P(zio->io_vd, !=, NULL);
|
|
ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE);
|
|
|
|
spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd);
|
|
|
|
ASSERT3P(cb, !=, NULL);
|
|
hdr = cb->l2rcb_hdr;
|
|
ASSERT3P(hdr, !=, NULL);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
|
|
/*
|
|
* If the data was read into a temporary buffer,
|
|
* move it and free the buffer.
|
|
*/
|
|
if (cb->l2rcb_abd != NULL) {
|
|
ASSERT3U(arc_hdr_size(hdr), <, zio->io_size);
|
|
if (zio->io_error == 0) {
|
|
if (using_rdata) {
|
|
abd_copy(hdr->b_crypt_hdr.b_rabd,
|
|
cb->l2rcb_abd, arc_hdr_size(hdr));
|
|
} else {
|
|
abd_copy(hdr->b_l1hdr.b_pabd,
|
|
cb->l2rcb_abd, arc_hdr_size(hdr));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The following must be done regardless of whether
|
|
* there was an error:
|
|
* - free the temporary buffer
|
|
* - point zio to the real ARC buffer
|
|
* - set zio size accordingly
|
|
* These are required because zio is either re-used for
|
|
* an I/O of the block in the case of the error
|
|
* or the zio is passed to arc_read_done() and it
|
|
* needs real data.
|
|
*/
|
|
abd_free(cb->l2rcb_abd);
|
|
zio->io_size = zio->io_orig_size = arc_hdr_size(hdr);
|
|
|
|
if (using_rdata) {
|
|
ASSERT(HDR_HAS_RABD(hdr));
|
|
zio->io_abd = zio->io_orig_abd =
|
|
hdr->b_crypt_hdr.b_rabd;
|
|
} else {
|
|
ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL);
|
|
zio->io_abd = zio->io_orig_abd = hdr->b_l1hdr.b_pabd;
|
|
}
|
|
}
|
|
|
|
ASSERT3P(zio->io_abd, !=, NULL);
|
|
|
|
/*
|
|
* Check this survived the L2ARC journey.
|
|
*/
|
|
ASSERT(zio->io_abd == hdr->b_l1hdr.b_pabd ||
|
|
(HDR_HAS_RABD(hdr) && zio->io_abd == hdr->b_crypt_hdr.b_rabd));
|
|
zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */
|
|
zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */
|
|
zio->io_prop.zp_complevel = hdr->b_complevel;
|
|
|
|
valid_cksum = arc_cksum_is_equal(hdr, zio);
|
|
|
|
/*
|
|
* b_rabd will always match the data as it exists on disk if it is
|
|
* being used. Therefore if we are reading into b_rabd we do not
|
|
* attempt to untransform the data.
|
|
*/
|
|
if (valid_cksum && !using_rdata)
|
|
tfm_error = l2arc_untransform(zio, cb);
|
|
|
|
if (valid_cksum && tfm_error == 0 && zio->io_error == 0 &&
|
|
!HDR_L2_EVICTED(hdr)) {
|
|
mutex_exit(hash_lock);
|
|
zio->io_private = hdr;
|
|
arc_read_done(zio);
|
|
} else {
|
|
/*
|
|
* Buffer didn't survive caching. Increment stats and
|
|
* reissue to the original storage device.
|
|
*/
|
|
if (zio->io_error != 0) {
|
|
ARCSTAT_BUMP(arcstat_l2_io_error);
|
|
} else {
|
|
zio->io_error = SET_ERROR(EIO);
|
|
}
|
|
if (!valid_cksum || tfm_error != 0)
|
|
ARCSTAT_BUMP(arcstat_l2_cksum_bad);
|
|
|
|
/*
|
|
* If there's no waiter, issue an async i/o to the primary
|
|
* storage now. If there *is* a waiter, the caller must
|
|
* issue the i/o in a context where it's OK to block.
|
|
*/
|
|
if (zio->io_waiter == NULL) {
|
|
zio_t *pio = zio_unique_parent(zio);
|
|
void *abd = (using_rdata) ?
|
|
hdr->b_crypt_hdr.b_rabd : hdr->b_l1hdr.b_pabd;
|
|
|
|
ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL);
|
|
|
|
zio = zio_read(pio, zio->io_spa, zio->io_bp,
|
|
abd, zio->io_size, arc_read_done,
|
|
hdr, zio->io_priority, cb->l2rcb_flags,
|
|
&cb->l2rcb_zb);
|
|
|
|
/*
|
|
* Original ZIO will be freed, so we need to update
|
|
* ARC header with the new ZIO pointer to be used
|
|
* by zio_change_priority() in arc_read().
|
|
*/
|
|
for (struct arc_callback *acb = hdr->b_l1hdr.b_acb;
|
|
acb != NULL; acb = acb->acb_next)
|
|
acb->acb_zio_head = zio;
|
|
|
|
mutex_exit(hash_lock);
|
|
zio_nowait(zio);
|
|
} else {
|
|
mutex_exit(hash_lock);
|
|
}
|
|
}
|
|
|
|
kmem_free(cb, sizeof (l2arc_read_callback_t));
|
|
}
|
|
|
|
/*
|
|
* This is the list priority from which the L2ARC will search for pages to
|
|
* cache. This is used within loops (0..3) to cycle through lists in the
|
|
* desired order. This order can have a significant effect on cache
|
|
* performance.
|
|
*
|
|
* Currently the metadata lists are hit first, MFU then MRU, followed by
|
|
* the data lists. This function returns a locked list, and also returns
|
|
* the lock pointer.
|
|
*/
|
|
static multilist_sublist_t *
|
|
l2arc_sublist_lock(int list_num)
|
|
{
|
|
multilist_t *ml = NULL;
|
|
unsigned int idx;
|
|
|
|
ASSERT(list_num >= 0 && list_num < L2ARC_FEED_TYPES);
|
|
|
|
switch (list_num) {
|
|
case 0:
|
|
ml = arc_mfu->arcs_list[ARC_BUFC_METADATA];
|
|
break;
|
|
case 1:
|
|
ml = arc_mru->arcs_list[ARC_BUFC_METADATA];
|
|
break;
|
|
case 2:
|
|
ml = arc_mfu->arcs_list[ARC_BUFC_DATA];
|
|
break;
|
|
case 3:
|
|
ml = arc_mru->arcs_list[ARC_BUFC_DATA];
|
|
break;
|
|
default:
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Return a randomly-selected sublist. This is acceptable
|
|
* because the caller feeds only a little bit of data for each
|
|
* call (8MB). Subsequent calls will result in different
|
|
* sublists being selected.
|
|
*/
|
|
idx = multilist_get_random_index(ml);
|
|
return (multilist_sublist_lock(ml, idx));
|
|
}
|
|
|
|
/*
|
|
* Calculates the maximum overhead of L2ARC metadata log blocks for a given
|
|
* L2ARC write size. l2arc_evict and l2arc_write_size need to include this
|
|
* overhead in processing to make sure there is enough headroom available
|
|
* when writing buffers.
|
|
*/
|
|
static inline uint64_t
|
|
l2arc_log_blk_overhead(uint64_t write_sz, l2arc_dev_t *dev)
|
|
{
|
|
if (dev->l2ad_log_entries == 0) {
|
|
return (0);
|
|
} else {
|
|
uint64_t log_entries = write_sz >> SPA_MINBLOCKSHIFT;
|
|
|
|
uint64_t log_blocks = (log_entries +
|
|
dev->l2ad_log_entries - 1) /
|
|
dev->l2ad_log_entries;
|
|
|
|
return (vdev_psize_to_asize(dev->l2ad_vdev,
|
|
sizeof (l2arc_log_blk_phys_t)) * log_blocks);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the device write hand to the distance specified in
|
|
* bytes. This distance may span populated buffers, it may span nothing.
|
|
* This is clearing a region on the L2ARC device ready for writing.
|
|
* If the 'all' boolean is set, every buffer is evicted.
|
|
*/
|
|
static void
|
|
l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all)
|
|
{
|
|
list_t *buflist;
|
|
arc_buf_hdr_t *hdr, *hdr_prev;
|
|
kmutex_t *hash_lock;
|
|
uint64_t taddr;
|
|
l2arc_lb_ptr_buf_t *lb_ptr_buf, *lb_ptr_buf_prev;
|
|
vdev_t *vd = dev->l2ad_vdev;
|
|
boolean_t rerun;
|
|
|
|
buflist = &dev->l2ad_buflist;
|
|
|
|
/*
|
|
* We need to add in the worst case scenario of log block overhead.
|
|
*/
|
|
distance += l2arc_log_blk_overhead(distance, dev);
|
|
if (vd->vdev_has_trim && l2arc_trim_ahead > 0) {
|
|
/*
|
|
* Trim ahead of the write size 64MB or (l2arc_trim_ahead/100)
|
|
* times the write size, whichever is greater.
|
|
*/
|
|
distance += MAX(64 * 1024 * 1024,
|
|
(distance * l2arc_trim_ahead) / 100);
|
|
}
|
|
|
|
top:
|
|
rerun = B_FALSE;
|
|
if (dev->l2ad_hand >= (dev->l2ad_end - distance)) {
|
|
/*
|
|
* When there is no space to accommodate upcoming writes,
|
|
* evict to the end. Then bump the write and evict hands
|
|
* to the start and iterate. This iteration does not
|
|
* happen indefinitely as we make sure in
|
|
* l2arc_write_size() that when the write hand is reset,
|
|
* the write size does not exceed the end of the device.
|
|
*/
|
|
rerun = B_TRUE;
|
|
taddr = dev->l2ad_end;
|
|
} else {
|
|
taddr = dev->l2ad_hand + distance;
|
|
}
|
|
DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist,
|
|
uint64_t, taddr, boolean_t, all);
|
|
|
|
if (!all) {
|
|
/*
|
|
* This check has to be placed after deciding whether to
|
|
* iterate (rerun).
|
|
*/
|
|
if (dev->l2ad_first) {
|
|
/*
|
|
* This is the first sweep through the device. There is
|
|
* nothing to evict. We have already trimmmed the
|
|
* whole device.
|
|
*/
|
|
goto out;
|
|
} else {
|
|
/*
|
|
* Trim the space to be evicted.
|
|
*/
|
|
if (vd->vdev_has_trim && dev->l2ad_evict < taddr &&
|
|
l2arc_trim_ahead > 0) {
|
|
/*
|
|
* We have to drop the spa_config lock because
|
|
* vdev_trim_range() will acquire it.
|
|
* l2ad_evict already accounts for the label
|
|
* size. To prevent vdev_trim_ranges() from
|
|
* adding it again, we subtract it from
|
|
* l2ad_evict.
|
|
*/
|
|
spa_config_exit(dev->l2ad_spa, SCL_L2ARC, dev);
|
|
vdev_trim_simple(vd,
|
|
dev->l2ad_evict - VDEV_LABEL_START_SIZE,
|
|
taddr - dev->l2ad_evict);
|
|
spa_config_enter(dev->l2ad_spa, SCL_L2ARC, dev,
|
|
RW_READER);
|
|
}
|
|
|
|
/*
|
|
* When rebuilding L2ARC we retrieve the evict hand
|
|
* from the header of the device. Of note, l2arc_evict()
|
|
* does not actually delete buffers from the cache
|
|
* device, but trimming may do so depending on the
|
|
* hardware implementation. Thus keeping track of the
|
|
* evict hand is useful.
|
|
*/
|
|
dev->l2ad_evict = MAX(dev->l2ad_evict, taddr);
|
|
}
|
|
}
|
|
|
|
retry:
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
/*
|
|
* We have to account for evicted log blocks. Run vdev_space_update()
|
|
* on log blocks whose offset (in bytes) is before the evicted offset
|
|
* (in bytes) by searching in the list of pointers to log blocks
|
|
* present in the L2ARC device.
|
|
*/
|
|
for (lb_ptr_buf = list_tail(&dev->l2ad_lbptr_list); lb_ptr_buf;
|
|
lb_ptr_buf = lb_ptr_buf_prev) {
|
|
|
|
lb_ptr_buf_prev = list_prev(&dev->l2ad_lbptr_list, lb_ptr_buf);
|
|
|
|
/* L2BLK_GET_PSIZE returns aligned size for log blocks */
|
|
uint64_t asize = L2BLK_GET_PSIZE(
|
|
(lb_ptr_buf->lb_ptr)->lbp_prop);
|
|
|
|
/*
|
|
* We don't worry about log blocks left behind (ie
|
|
* lbp_payload_start < l2ad_hand) because l2arc_write_buffers()
|
|
* will never write more than l2arc_evict() evicts.
|
|
*/
|
|
if (!all && l2arc_log_blkptr_valid(dev, lb_ptr_buf->lb_ptr)) {
|
|
break;
|
|
} else {
|
|
vdev_space_update(vd, -asize, 0, 0);
|
|
ARCSTAT_INCR(arcstat_l2_log_blk_asize, -asize);
|
|
ARCSTAT_BUMPDOWN(arcstat_l2_log_blk_count);
|
|
zfs_refcount_remove_many(&dev->l2ad_lb_asize, asize,
|
|
lb_ptr_buf);
|
|
zfs_refcount_remove(&dev->l2ad_lb_count, lb_ptr_buf);
|
|
list_remove(&dev->l2ad_lbptr_list, lb_ptr_buf);
|
|
kmem_free(lb_ptr_buf->lb_ptr,
|
|
sizeof (l2arc_log_blkptr_t));
|
|
kmem_free(lb_ptr_buf, sizeof (l2arc_lb_ptr_buf_t));
|
|
}
|
|
}
|
|
|
|
for (hdr = list_tail(buflist); hdr; hdr = hdr_prev) {
|
|
hdr_prev = list_prev(buflist, hdr);
|
|
|
|
ASSERT(!HDR_EMPTY(hdr));
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We cannot use mutex_enter or else we can deadlock
|
|
* with l2arc_write_buffers (due to swapping the order
|
|
* the hash lock and l2ad_mtx are taken).
|
|
*/
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Missed the hash lock. Retry.
|
|
*/
|
|
ARCSTAT_BUMP(arcstat_l2_evict_lock_retry);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
mutex_enter(hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto retry;
|
|
}
|
|
|
|
/*
|
|
* A header can't be on this list if it doesn't have L2 header.
|
|
*/
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
/* Ensure this header has finished being written. */
|
|
ASSERT(!HDR_L2_WRITING(hdr));
|
|
ASSERT(!HDR_L2_WRITE_HEAD(hdr));
|
|
|
|
if (!all && (hdr->b_l2hdr.b_daddr >= dev->l2ad_evict ||
|
|
hdr->b_l2hdr.b_daddr < dev->l2ad_hand)) {
|
|
/*
|
|
* We've evicted to the target address,
|
|
* or the end of the device.
|
|
*/
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
if (!HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(!HDR_L2_READING(hdr));
|
|
/*
|
|
* This doesn't exist in the ARC. Destroy.
|
|
* arc_hdr_destroy() will call list_remove()
|
|
* and decrement arcstat_l2_lsize.
|
|
*/
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
arc_hdr_destroy(hdr);
|
|
} else {
|
|
ASSERT(hdr->b_l1hdr.b_state != arc_l2c_only);
|
|
ARCSTAT_BUMP(arcstat_l2_evict_l1cached);
|
|
/*
|
|
* Invalidate issued or about to be issued
|
|
* reads, since we may be about to write
|
|
* over this location.
|
|
*/
|
|
if (HDR_L2_READING(hdr)) {
|
|
ARCSTAT_BUMP(arcstat_l2_evict_reading);
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_L2_EVICTED);
|
|
}
|
|
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
}
|
|
mutex_exit(hash_lock);
|
|
}
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
out:
|
|
/*
|
|
* We need to check if we evict all buffers, otherwise we may iterate
|
|
* unnecessarily.
|
|
*/
|
|
if (!all && rerun) {
|
|
/*
|
|
* Bump device hand to the device start if it is approaching the
|
|
* end. l2arc_evict() has already evicted ahead for this case.
|
|
*/
|
|
dev->l2ad_hand = dev->l2ad_start;
|
|
dev->l2ad_evict = dev->l2ad_start;
|
|
dev->l2ad_first = B_FALSE;
|
|
goto top;
|
|
}
|
|
|
|
ASSERT3U(dev->l2ad_hand + distance, <, dev->l2ad_end);
|
|
if (!dev->l2ad_first)
|
|
ASSERT3U(dev->l2ad_hand, <, dev->l2ad_evict);
|
|
}
|
|
|
|
/*
|
|
* Handle any abd transforms that might be required for writing to the L2ARC.
|
|
* If successful, this function will always return an abd with the data
|
|
* transformed as it is on disk in a new abd of asize bytes.
|
|
*/
|
|
static int
|
|
l2arc_apply_transforms(spa_t *spa, arc_buf_hdr_t *hdr, uint64_t asize,
|
|
abd_t **abd_out)
|
|
{
|
|
int ret;
|
|
void *tmp = NULL;
|
|
abd_t *cabd = NULL, *eabd = NULL, *to_write = hdr->b_l1hdr.b_pabd;
|
|
enum zio_compress compress = HDR_GET_COMPRESS(hdr);
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
uint64_t size = arc_hdr_size(hdr);
|
|
boolean_t ismd = HDR_ISTYPE_METADATA(hdr);
|
|
boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS);
|
|
dsl_crypto_key_t *dck = NULL;
|
|
uint8_t mac[ZIO_DATA_MAC_LEN] = { 0 };
|
|
boolean_t no_crypt = B_FALSE;
|
|
|
|
ASSERT((HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
|
|
!HDR_COMPRESSION_ENABLED(hdr)) ||
|
|
HDR_ENCRYPTED(hdr) || HDR_SHARED_DATA(hdr) || psize != asize);
|
|
ASSERT3U(psize, <=, asize);
|
|
|
|
/*
|
|
* If this data simply needs its own buffer, we simply allocate it
|
|
* and copy the data. This may be done to eliminate a dependency on a
|
|
* shared buffer or to reallocate the buffer to match asize.
|
|
*/
|
|
if (HDR_HAS_RABD(hdr) && asize != psize) {
|
|
ASSERT3U(asize, >=, psize);
|
|
to_write = abd_alloc_for_io(asize, ismd);
|
|
abd_copy(to_write, hdr->b_crypt_hdr.b_rabd, psize);
|
|
if (psize != asize)
|
|
abd_zero_off(to_write, psize, asize - psize);
|
|
goto out;
|
|
}
|
|
|
|
if ((compress == ZIO_COMPRESS_OFF || HDR_COMPRESSION_ENABLED(hdr)) &&
|
|
!HDR_ENCRYPTED(hdr)) {
|
|
ASSERT3U(size, ==, psize);
|
|
to_write = abd_alloc_for_io(asize, ismd);
|
|
abd_copy(to_write, hdr->b_l1hdr.b_pabd, size);
|
|
if (size != asize)
|
|
abd_zero_off(to_write, size, asize - size);
|
|
goto out;
|
|
}
|
|
|
|
if (compress != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) {
|
|
cabd = abd_alloc_for_io(asize, ismd);
|
|
tmp = abd_borrow_buf(cabd, asize);
|
|
|
|
psize = zio_compress_data(compress, to_write, tmp, size,
|
|
hdr->b_complevel);
|
|
|
|
if (psize >= size) {
|
|
abd_return_buf(cabd, tmp, asize);
|
|
HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_OFF);
|
|
to_write = cabd;
|
|
abd_copy(to_write, hdr->b_l1hdr.b_pabd, size);
|
|
if (size != asize)
|
|
abd_zero_off(to_write, size, asize - size);
|
|
goto encrypt;
|
|
}
|
|
ASSERT3U(psize, <=, HDR_GET_PSIZE(hdr));
|
|
if (psize < asize)
|
|
bzero((char *)tmp + psize, asize - psize);
|
|
psize = HDR_GET_PSIZE(hdr);
|
|
abd_return_buf_copy(cabd, tmp, asize);
|
|
to_write = cabd;
|
|
}
|
|
|
|
encrypt:
|
|
if (HDR_ENCRYPTED(hdr)) {
|
|
eabd = abd_alloc_for_io(asize, ismd);
|
|
|
|
/*
|
|
* If the dataset was disowned before the buffer
|
|
* made it to this point, the key to re-encrypt
|
|
* it won't be available. In this case we simply
|
|
* won't write the buffer to the L2ARC.
|
|
*/
|
|
ret = spa_keystore_lookup_key(spa, hdr->b_crypt_hdr.b_dsobj,
|
|
FTAG, &dck);
|
|
if (ret != 0)
|
|
goto error;
|
|
|
|
ret = zio_do_crypt_abd(B_TRUE, &dck->dck_key,
|
|
hdr->b_crypt_hdr.b_ot, bswap, hdr->b_crypt_hdr.b_salt,
|
|
hdr->b_crypt_hdr.b_iv, mac, psize, to_write, eabd,
|
|
&no_crypt);
|
|
if (ret != 0)
|
|
goto error;
|
|
|
|
if (no_crypt)
|
|
abd_copy(eabd, to_write, psize);
|
|
|
|
if (psize != asize)
|
|
abd_zero_off(eabd, psize, asize - psize);
|
|
|
|
/* assert that the MAC we got here matches the one we saved */
|
|
ASSERT0(bcmp(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN));
|
|
spa_keystore_dsl_key_rele(spa, dck, FTAG);
|
|
|
|
if (to_write == cabd)
|
|
abd_free(cabd);
|
|
|
|
to_write = eabd;
|
|
}
|
|
|
|
out:
|
|
ASSERT3P(to_write, !=, hdr->b_l1hdr.b_pabd);
|
|
*abd_out = to_write;
|
|
return (0);
|
|
|
|
error:
|
|
if (dck != NULL)
|
|
spa_keystore_dsl_key_rele(spa, dck, FTAG);
|
|
if (cabd != NULL)
|
|
abd_free(cabd);
|
|
if (eabd != NULL)
|
|
abd_free(eabd);
|
|
|
|
*abd_out = NULL;
|
|
return (ret);
|
|
}
|
|
|
|
static void
|
|
l2arc_blk_fetch_done(zio_t *zio)
|
|
{
|
|
l2arc_read_callback_t *cb;
|
|
|
|
cb = zio->io_private;
|
|
if (cb->l2rcb_abd != NULL)
|
|
abd_put(cb->l2rcb_abd);
|
|
kmem_free(cb, sizeof (l2arc_read_callback_t));
|
|
}
|
|
|
|
/*
|
|
* Find and write ARC buffers to the L2ARC device.
|
|
*
|
|
* An ARC_FLAG_L2_WRITING flag is set so that the L2ARC buffers are not valid
|
|
* for reading until they have completed writing.
|
|
* The headroom_boost is an in-out parameter used to maintain headroom boost
|
|
* state between calls to this function.
|
|
*
|
|
* Returns the number of bytes actually written (which may be smaller than
|
|
* the delta by which the device hand has changed due to alignment and the
|
|
* writing of log blocks).
|
|
*/
|
|
static uint64_t
|
|
l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
|
|
{
|
|
arc_buf_hdr_t *hdr, *hdr_prev, *head;
|
|
uint64_t write_asize, write_psize, write_lsize, headroom;
|
|
boolean_t full;
|
|
l2arc_write_callback_t *cb = NULL;
|
|
zio_t *pio, *wzio;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
|
|
ASSERT3P(dev->l2ad_vdev, !=, NULL);
|
|
|
|
pio = NULL;
|
|
write_lsize = write_asize = write_psize = 0;
|
|
full = B_FALSE;
|
|
head = kmem_cache_alloc(hdr_l2only_cache, KM_PUSHPAGE);
|
|
arc_hdr_set_flags(head, ARC_FLAG_L2_WRITE_HEAD | ARC_FLAG_HAS_L2HDR);
|
|
|
|
/*
|
|
* Copy buffers for L2ARC writing.
|
|
*/
|
|
for (int try = 0; try < L2ARC_FEED_TYPES; try++) {
|
|
multilist_sublist_t *mls = l2arc_sublist_lock(try);
|
|
uint64_t passed_sz = 0;
|
|
|
|
VERIFY3P(mls, !=, NULL);
|
|
|
|
/*
|
|
* L2ARC fast warmup.
|
|
*
|
|
* Until the ARC is warm and starts to evict, read from the
|
|
* head of the ARC lists rather than the tail.
|
|
*/
|
|
if (arc_warm == B_FALSE)
|
|
hdr = multilist_sublist_head(mls);
|
|
else
|
|
hdr = multilist_sublist_tail(mls);
|
|
|
|
headroom = target_sz * l2arc_headroom;
|
|
if (zfs_compressed_arc_enabled)
|
|
headroom = (headroom * l2arc_headroom_boost) / 100;
|
|
|
|
for (; hdr; hdr = hdr_prev) {
|
|
kmutex_t *hash_lock;
|
|
abd_t *to_write = NULL;
|
|
|
|
if (arc_warm == B_FALSE)
|
|
hdr_prev = multilist_sublist_next(mls, hdr);
|
|
else
|
|
hdr_prev = multilist_sublist_prev(mls, hdr);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Skip this buffer rather than waiting.
|
|
*/
|
|
continue;
|
|
}
|
|
|
|
passed_sz += HDR_GET_LSIZE(hdr);
|
|
if (l2arc_headroom != 0 && passed_sz > headroom) {
|
|
/*
|
|
* Searched too far.
|
|
*/
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
if (!l2arc_write_eligible(guid, hdr)) {
|
|
mutex_exit(hash_lock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* We rely on the L1 portion of the header below, so
|
|
* it's invalid for this header to have been evicted out
|
|
* of the ghost cache, prior to being written out. The
|
|
* ARC_FLAG_L2_WRITING bit ensures this won't happen.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
ASSERT3U(HDR_GET_PSIZE(hdr), >, 0);
|
|
ASSERT3U(arc_hdr_size(hdr), >, 0);
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL ||
|
|
HDR_HAS_RABD(hdr));
|
|
uint64_t psize = HDR_GET_PSIZE(hdr);
|
|
uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev,
|
|
psize);
|
|
|
|
if ((write_asize + asize) > target_sz) {
|
|
full = B_TRUE;
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We rely on the L1 portion of the header below, so
|
|
* it's invalid for this header to have been evicted out
|
|
* of the ghost cache, prior to being written out. The
|
|
* ARC_FLAG_L2_WRITING bit ensures this won't happen.
|
|
*/
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_L2_WRITING);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
ASSERT3U(HDR_GET_PSIZE(hdr), >, 0);
|
|
ASSERT(hdr->b_l1hdr.b_pabd != NULL ||
|
|
HDR_HAS_RABD(hdr));
|
|
ASSERT3U(arc_hdr_size(hdr), >, 0);
|
|
|
|
/*
|
|
* If this header has b_rabd, we can use this since it
|
|
* must always match the data exactly as it exists on
|
|
* disk. Otherwise, the L2ARC can normally use the
|
|
* hdr's data, but if we're sharing data between the
|
|
* hdr and one of its bufs, L2ARC needs its own copy of
|
|
* the data so that the ZIO below can't race with the
|
|
* buf consumer. To ensure that this copy will be
|
|
* available for the lifetime of the ZIO and be cleaned
|
|
* up afterwards, we add it to the l2arc_free_on_write
|
|
* queue. If we need to apply any transforms to the
|
|
* data (compression, encryption) we will also need the
|
|
* extra buffer.
|
|
*/
|
|
if (HDR_HAS_RABD(hdr) && psize == asize) {
|
|
to_write = hdr->b_crypt_hdr.b_rabd;
|
|
} else if ((HDR_COMPRESSION_ENABLED(hdr) ||
|
|
HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF) &&
|
|
!HDR_ENCRYPTED(hdr) && !HDR_SHARED_DATA(hdr) &&
|
|
psize == asize) {
|
|
to_write = hdr->b_l1hdr.b_pabd;
|
|
} else {
|
|
int ret;
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
|
|
ret = l2arc_apply_transforms(spa, hdr, asize,
|
|
&to_write);
|
|
if (ret != 0) {
|
|
arc_hdr_clear_flags(hdr,
|
|
ARC_FLAG_L2_WRITING);
|
|
mutex_exit(hash_lock);
|
|
continue;
|
|
}
|
|
|
|
l2arc_free_abd_on_write(to_write, asize, type);
|
|
}
|
|
|
|
if (pio == NULL) {
|
|
/*
|
|
* Insert a dummy header on the buflist so
|
|
* l2arc_write_done() can find where the
|
|
* write buffers begin without searching.
|
|
*/
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_head(&dev->l2ad_buflist, head);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
cb = kmem_alloc(
|
|
sizeof (l2arc_write_callback_t), KM_SLEEP);
|
|
cb->l2wcb_dev = dev;
|
|
cb->l2wcb_head = head;
|
|
/*
|
|
* Create a list to save allocated abd buffers
|
|
* for l2arc_log_blk_commit().
|
|
*/
|
|
list_create(&cb->l2wcb_abd_list,
|
|
sizeof (l2arc_lb_abd_buf_t),
|
|
offsetof(l2arc_lb_abd_buf_t, node));
|
|
pio = zio_root(spa, l2arc_write_done, cb,
|
|
ZIO_FLAG_CANFAIL);
|
|
}
|
|
|
|
hdr->b_l2hdr.b_dev = dev;
|
|
hdr->b_l2hdr.b_hits = 0;
|
|
|
|
hdr->b_l2hdr.b_daddr = dev->l2ad_hand;
|
|
arc_hdr_set_flags(hdr, ARC_FLAG_HAS_L2HDR);
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_head(&dev->l2ad_buflist, hdr);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
(void) zfs_refcount_add_many(&dev->l2ad_alloc,
|
|
arc_hdr_size(hdr), hdr);
|
|
|
|
wzio = zio_write_phys(pio, dev->l2ad_vdev,
|
|
hdr->b_l2hdr.b_daddr, asize, to_write,
|
|
ZIO_CHECKSUM_OFF, NULL, hdr,
|
|
ZIO_PRIORITY_ASYNC_WRITE,
|
|
ZIO_FLAG_CANFAIL, B_FALSE);
|
|
|
|
write_lsize += HDR_GET_LSIZE(hdr);
|
|
DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev,
|
|
zio_t *, wzio);
|
|
|
|
write_psize += psize;
|
|
write_asize += asize;
|
|
dev->l2ad_hand += asize;
|
|
vdev_space_update(dev->l2ad_vdev, asize, 0, 0);
|
|
|
|
mutex_exit(hash_lock);
|
|
|
|
/*
|
|
* Append buf info to current log and commit if full.
|
|
* arcstat_l2_{size,asize} kstats are updated
|
|
* internally.
|
|
*/
|
|
if (l2arc_log_blk_insert(dev, hdr))
|
|
l2arc_log_blk_commit(dev, pio, cb);
|
|
|
|
zio_nowait(wzio);
|
|
}
|
|
|
|
multilist_sublist_unlock(mls);
|
|
|
|
if (full == B_TRUE)
|
|
break;
|
|
}
|
|
|
|
/* No buffers selected for writing? */
|
|
if (pio == NULL) {
|
|
ASSERT0(write_lsize);
|
|
ASSERT(!HDR_HAS_L1HDR(head));
|
|
kmem_cache_free(hdr_l2only_cache, head);
|
|
|
|
/*
|
|
* Although we did not write any buffers l2ad_evict may
|
|
* have advanced.
|
|
*/
|
|
l2arc_dev_hdr_update(dev);
|
|
|
|
return (0);
|
|
}
|
|
|
|
if (!dev->l2ad_first)
|
|
ASSERT3U(dev->l2ad_hand, <=, dev->l2ad_evict);
|
|
|
|
ASSERT3U(write_asize, <=, target_sz);
|
|
ARCSTAT_BUMP(arcstat_l2_writes_sent);
|
|
ARCSTAT_INCR(arcstat_l2_write_bytes, write_psize);
|
|
ARCSTAT_INCR(arcstat_l2_lsize, write_lsize);
|
|
ARCSTAT_INCR(arcstat_l2_psize, write_psize);
|
|
|
|
dev->l2ad_writing = B_TRUE;
|
|
(void) zio_wait(pio);
|
|
dev->l2ad_writing = B_FALSE;
|
|
|
|
/*
|
|
* Update the device header after the zio completes as
|
|
* l2arc_write_done() may have updated the memory holding the log block
|
|
* pointers in the device header.
|
|
*/
|
|
l2arc_dev_hdr_update(dev);
|
|
|
|
return (write_asize);
|
|
}
|
|
|
|
static boolean_t
|
|
l2arc_hdr_limit_reached(void)
|
|
{
|
|
int64_t s = aggsum_upper_bound(&astat_l2_hdr_size);
|
|
|
|
return (arc_reclaim_needed() || (s > arc_meta_limit * 3 / 4) ||
|
|
(s > (arc_warm ? arc_c : arc_c_max) * l2arc_meta_percent / 100));
|
|
}
|
|
|
|
/*
|
|
* This thread feeds the L2ARC at regular intervals. This is the beating
|
|
* heart of the L2ARC.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
l2arc_feed_thread(void *unused)
|
|
{
|
|
callb_cpr_t cpr;
|
|
l2arc_dev_t *dev;
|
|
spa_t *spa;
|
|
uint64_t size, wrote;
|
|
clock_t begin, next = ddi_get_lbolt();
|
|
fstrans_cookie_t cookie;
|
|
|
|
CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG);
|
|
|
|
mutex_enter(&l2arc_feed_thr_lock);
|
|
|
|
cookie = spl_fstrans_mark();
|
|
while (l2arc_thread_exit == 0) {
|
|
CALLB_CPR_SAFE_BEGIN(&cpr);
|
|
(void) cv_timedwait_sig(&l2arc_feed_thr_cv,
|
|
&l2arc_feed_thr_lock, next);
|
|
CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock);
|
|
next = ddi_get_lbolt() + hz;
|
|
|
|
/*
|
|
* Quick check for L2ARC devices.
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
if (l2arc_ndev == 0) {
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
continue;
|
|
}
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
begin = ddi_get_lbolt();
|
|
|
|
/*
|
|
* This selects the next l2arc device to write to, and in
|
|
* doing so the next spa to feed from: dev->l2ad_spa. This
|
|
* will return NULL if there are now no l2arc devices or if
|
|
* they are all faulted.
|
|
*
|
|
* If a device is returned, its spa's config lock is also
|
|
* held to prevent device removal. l2arc_dev_get_next()
|
|
* will grab and release l2arc_dev_mtx.
|
|
*/
|
|
if ((dev = l2arc_dev_get_next()) == NULL)
|
|
continue;
|
|
|
|
spa = dev->l2ad_spa;
|
|
ASSERT3P(spa, !=, NULL);
|
|
|
|
/*
|
|
* If the pool is read-only then force the feed thread to
|
|
* sleep a little longer.
|
|
*/
|
|
if (!spa_writeable(spa)) {
|
|
next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz;
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Avoid contributing to memory pressure.
|
|
*/
|
|
if (l2arc_hdr_limit_reached()) {
|
|
ARCSTAT_BUMP(arcstat_l2_abort_lowmem);
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
continue;
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_l2_feeds);
|
|
|
|
size = l2arc_write_size(dev);
|
|
|
|
/*
|
|
* Evict L2ARC buffers that will be overwritten.
|
|
*/
|
|
l2arc_evict(dev, size, B_FALSE);
|
|
|
|
/*
|
|
* Write ARC buffers.
|
|
*/
|
|
wrote = l2arc_write_buffers(spa, dev, size);
|
|
|
|
/*
|
|
* Calculate interval between writes.
|
|
*/
|
|
next = l2arc_write_interval(begin, size, wrote);
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
}
|
|
spl_fstrans_unmark(cookie);
|
|
|
|
l2arc_thread_exit = 0;
|
|
cv_broadcast(&l2arc_feed_thr_cv);
|
|
CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */
|
|
thread_exit();
|
|
}
|
|
|
|
boolean_t
|
|
l2arc_vdev_present(vdev_t *vd)
|
|
{
|
|
return (l2arc_vdev_get(vd) != NULL);
|
|
}
|
|
|
|
/*
|
|
* Returns the l2arc_dev_t associated with a particular vdev_t or NULL if
|
|
* the vdev_t isn't an L2ARC device.
|
|
*/
|
|
l2arc_dev_t *
|
|
l2arc_vdev_get(vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *dev;
|
|
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
for (dev = list_head(l2arc_dev_list); dev != NULL;
|
|
dev = list_next(l2arc_dev_list, dev)) {
|
|
if (dev->l2ad_vdev == vd)
|
|
break;
|
|
}
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
return (dev);
|
|
}
|
|
|
|
/*
|
|
* Add a vdev for use by the L2ARC. By this point the spa has already
|
|
* validated the vdev and opened it.
|
|
*/
|
|
void
|
|
l2arc_add_vdev(spa_t *spa, vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *adddev;
|
|
uint64_t l2dhdr_asize;
|
|
|
|
ASSERT(!l2arc_vdev_present(vd));
|
|
|
|
vdev_ashift_optimize(vd);
|
|
|
|
/*
|
|
* Create a new l2arc device entry.
|
|
*/
|
|
adddev = vmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP);
|
|
adddev->l2ad_spa = spa;
|
|
adddev->l2ad_vdev = vd;
|
|
/* leave extra size for an l2arc device header */
|
|
l2dhdr_asize = adddev->l2ad_dev_hdr_asize =
|
|
MAX(sizeof (*adddev->l2ad_dev_hdr), 1 << vd->vdev_ashift);
|
|
adddev->l2ad_start = VDEV_LABEL_START_SIZE + l2dhdr_asize;
|
|
adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd);
|
|
ASSERT3U(adddev->l2ad_start, <, adddev->l2ad_end);
|
|
adddev->l2ad_hand = adddev->l2ad_start;
|
|
adddev->l2ad_evict = adddev->l2ad_start;
|
|
adddev->l2ad_first = B_TRUE;
|
|
adddev->l2ad_writing = B_FALSE;
|
|
adddev->l2ad_trim_all = B_FALSE;
|
|
list_link_init(&adddev->l2ad_node);
|
|
adddev->l2ad_dev_hdr = kmem_zalloc(l2dhdr_asize, KM_SLEEP);
|
|
|
|
mutex_init(&adddev->l2ad_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
/*
|
|
* This is a list of all ARC buffers that are still valid on the
|
|
* device.
|
|
*/
|
|
list_create(&adddev->l2ad_buflist, sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l2hdr.b_l2node));
|
|
|
|
/*
|
|
* This is a list of pointers to log blocks that are still present
|
|
* on the device.
|
|
*/
|
|
list_create(&adddev->l2ad_lbptr_list, sizeof (l2arc_lb_ptr_buf_t),
|
|
offsetof(l2arc_lb_ptr_buf_t, node));
|
|
|
|
vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand);
|
|
zfs_refcount_create(&adddev->l2ad_alloc);
|
|
zfs_refcount_create(&adddev->l2ad_lb_asize);
|
|
zfs_refcount_create(&adddev->l2ad_lb_count);
|
|
|
|
/*
|
|
* Add device to global list
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
list_insert_head(l2arc_dev_list, adddev);
|
|
atomic_inc_64(&l2arc_ndev);
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
/*
|
|
* Decide if vdev is eligible for L2ARC rebuild
|
|
*/
|
|
l2arc_rebuild_vdev(adddev->l2ad_vdev, B_FALSE);
|
|
}
|
|
|
|
void
|
|
l2arc_rebuild_vdev(vdev_t *vd, boolean_t reopen)
|
|
{
|
|
l2arc_dev_t *dev = NULL;
|
|
l2arc_dev_hdr_phys_t *l2dhdr;
|
|
uint64_t l2dhdr_asize;
|
|
spa_t *spa;
|
|
int err;
|
|
boolean_t l2dhdr_valid = B_TRUE;
|
|
|
|
dev = l2arc_vdev_get(vd);
|
|
ASSERT3P(dev, !=, NULL);
|
|
spa = dev->l2ad_spa;
|
|
l2dhdr = dev->l2ad_dev_hdr;
|
|
l2dhdr_asize = dev->l2ad_dev_hdr_asize;
|
|
|
|
/*
|
|
* The L2ARC has to hold at least the payload of one log block for
|
|
* them to be restored (persistent L2ARC). The payload of a log block
|
|
* depends on the amount of its log entries. We always write log blocks
|
|
* with 1022 entries. How many of them are committed or restored depends
|
|
* on the size of the L2ARC device. Thus the maximum payload of
|
|
* one log block is 1022 * SPA_MAXBLOCKSIZE = 16GB. If the L2ARC device
|
|
* is less than that, we reduce the amount of committed and restored
|
|
* log entries per block so as to enable persistence.
|
|
*/
|
|
if (dev->l2ad_end < l2arc_rebuild_blocks_min_l2size) {
|
|
dev->l2ad_log_entries = 0;
|
|
} else {
|
|
dev->l2ad_log_entries = MIN((dev->l2ad_end -
|
|
dev->l2ad_start) >> SPA_MAXBLOCKSHIFT,
|
|
L2ARC_LOG_BLK_MAX_ENTRIES);
|
|
}
|
|
|
|
/*
|
|
* Read the device header, if an error is returned do not rebuild L2ARC.
|
|
*/
|
|
if ((err = l2arc_dev_hdr_read(dev)) != 0)
|
|
l2dhdr_valid = B_FALSE;
|
|
|
|
if (l2dhdr_valid && dev->l2ad_log_entries > 0) {
|
|
/*
|
|
* If we are onlining a cache device (vdev_reopen) that was
|
|
* still present (l2arc_vdev_present()) and rebuild is enabled,
|
|
* we should evict all ARC buffers and pointers to log blocks
|
|
* and reclaim their space before restoring its contents to
|
|
* L2ARC.
|
|
*/
|
|
if (reopen) {
|
|
if (!l2arc_rebuild_enabled) {
|
|
return;
|
|
} else {
|
|
l2arc_evict(dev, 0, B_TRUE);
|
|
/* start a new log block */
|
|
dev->l2ad_log_ent_idx = 0;
|
|
dev->l2ad_log_blk_payload_asize = 0;
|
|
dev->l2ad_log_blk_payload_start = 0;
|
|
}
|
|
}
|
|
/*
|
|
* Just mark the device as pending for a rebuild. We won't
|
|
* be starting a rebuild in line here as it would block pool
|
|
* import. Instead spa_load_impl will hand that off to an
|
|
* async task which will call l2arc_spa_rebuild_start.
|
|
*/
|
|
dev->l2ad_rebuild = B_TRUE;
|
|
} else if (spa_writeable(spa)) {
|
|
/*
|
|
* In this case TRIM the whole device if l2arc_trim_ahead > 0,
|
|
* otherwise create a new header. We zero out the memory holding
|
|
* the header to reset dh_start_lbps. If we TRIM the whole
|
|
* device the new header will be written by
|
|
* vdev_trim_l2arc_thread() at the end of the TRIM to update the
|
|
* trim_state in the header too. When reading the header, if
|
|
* trim_state is not VDEV_TRIM_COMPLETE and l2arc_trim_ahead > 0
|
|
* we opt to TRIM the whole device again.
|
|
*/
|
|
if (l2arc_trim_ahead > 0) {
|
|
dev->l2ad_trim_all = B_TRUE;
|
|
} else {
|
|
bzero(l2dhdr, l2dhdr_asize);
|
|
l2arc_dev_hdr_update(dev);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove a vdev from the L2ARC.
|
|
*/
|
|
void
|
|
l2arc_remove_vdev(vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *remdev = NULL;
|
|
|
|
/*
|
|
* Find the device by vdev
|
|
*/
|
|
remdev = l2arc_vdev_get(vd);
|
|
ASSERT3P(remdev, !=, NULL);
|
|
|
|
/*
|
|
* Cancel any ongoing or scheduled rebuild.
|
|
*/
|
|
mutex_enter(&l2arc_rebuild_thr_lock);
|
|
if (remdev->l2ad_rebuild_began == B_TRUE) {
|
|
remdev->l2ad_rebuild_cancel = B_TRUE;
|
|
while (remdev->l2ad_rebuild == B_TRUE)
|
|
cv_wait(&l2arc_rebuild_thr_cv, &l2arc_rebuild_thr_lock);
|
|
}
|
|
mutex_exit(&l2arc_rebuild_thr_lock);
|
|
|
|
/*
|
|
* Remove device from global list
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
list_remove(l2arc_dev_list, remdev);
|
|
l2arc_dev_last = NULL; /* may have been invalidated */
|
|
atomic_dec_64(&l2arc_ndev);
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
/*
|
|
* Clear all buflists and ARC references. L2ARC device flush.
|
|
*/
|
|
l2arc_evict(remdev, 0, B_TRUE);
|
|
list_destroy(&remdev->l2ad_buflist);
|
|
ASSERT(list_is_empty(&remdev->l2ad_lbptr_list));
|
|
list_destroy(&remdev->l2ad_lbptr_list);
|
|
mutex_destroy(&remdev->l2ad_mtx);
|
|
zfs_refcount_destroy(&remdev->l2ad_alloc);
|
|
zfs_refcount_destroy(&remdev->l2ad_lb_asize);
|
|
zfs_refcount_destroy(&remdev->l2ad_lb_count);
|
|
kmem_free(remdev->l2ad_dev_hdr, remdev->l2ad_dev_hdr_asize);
|
|
vmem_free(remdev, sizeof (l2arc_dev_t));
|
|
}
|
|
|
|
void
|
|
l2arc_init(void)
|
|
{
|
|
l2arc_thread_exit = 0;
|
|
l2arc_ndev = 0;
|
|
l2arc_writes_sent = 0;
|
|
l2arc_writes_done = 0;
|
|
|
|
mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL);
|
|
mutex_init(&l2arc_rebuild_thr_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
cv_init(&l2arc_rebuild_thr_cv, NULL, CV_DEFAULT, NULL);
|
|
mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
|
|
l2arc_dev_list = &L2ARC_dev_list;
|
|
l2arc_free_on_write = &L2ARC_free_on_write;
|
|
list_create(l2arc_dev_list, sizeof (l2arc_dev_t),
|
|
offsetof(l2arc_dev_t, l2ad_node));
|
|
list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t),
|
|
offsetof(l2arc_data_free_t, l2df_list_node));
|
|
}
|
|
|
|
void
|
|
l2arc_fini(void)
|
|
{
|
|
mutex_destroy(&l2arc_feed_thr_lock);
|
|
cv_destroy(&l2arc_feed_thr_cv);
|
|
mutex_destroy(&l2arc_rebuild_thr_lock);
|
|
cv_destroy(&l2arc_rebuild_thr_cv);
|
|
mutex_destroy(&l2arc_dev_mtx);
|
|
mutex_destroy(&l2arc_free_on_write_mtx);
|
|
|
|
list_destroy(l2arc_dev_list);
|
|
list_destroy(l2arc_free_on_write);
|
|
}
|
|
|
|
void
|
|
l2arc_start(void)
|
|
{
|
|
if (!(spa_mode_global & SPA_MODE_WRITE))
|
|
return;
|
|
|
|
(void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0,
|
|
TS_RUN, defclsyspri);
|
|
}
|
|
|
|
void
|
|
l2arc_stop(void)
|
|
{
|
|
if (!(spa_mode_global & SPA_MODE_WRITE))
|
|
return;
|
|
|
|
mutex_enter(&l2arc_feed_thr_lock);
|
|
cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */
|
|
l2arc_thread_exit = 1;
|
|
while (l2arc_thread_exit != 0)
|
|
cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock);
|
|
mutex_exit(&l2arc_feed_thr_lock);
|
|
}
|
|
|
|
/*
|
|
* Punches out rebuild threads for the L2ARC devices in a spa. This should
|
|
* be called after pool import from the spa async thread, since starting
|
|
* these threads directly from spa_import() will make them part of the
|
|
* "zpool import" context and delay process exit (and thus pool import).
|
|
*/
|
|
void
|
|
l2arc_spa_rebuild_start(spa_t *spa)
|
|
{
|
|
ASSERT(MUTEX_HELD(&spa_namespace_lock));
|
|
|
|
/*
|
|
* Locate the spa's l2arc devices and kick off rebuild threads.
|
|
*/
|
|
for (int i = 0; i < spa->spa_l2cache.sav_count; i++) {
|
|
l2arc_dev_t *dev =
|
|
l2arc_vdev_get(spa->spa_l2cache.sav_vdevs[i]);
|
|
if (dev == NULL) {
|
|
/* Don't attempt a rebuild if the vdev is UNAVAIL */
|
|
continue;
|
|
}
|
|
mutex_enter(&l2arc_rebuild_thr_lock);
|
|
if (dev->l2ad_rebuild && !dev->l2ad_rebuild_cancel) {
|
|
dev->l2ad_rebuild_began = B_TRUE;
|
|
(void) thread_create(NULL, 0, l2arc_dev_rebuild_thread,
|
|
dev, 0, &p0, TS_RUN, minclsyspri);
|
|
}
|
|
mutex_exit(&l2arc_rebuild_thr_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Main entry point for L2ARC rebuilding.
|
|
*/
|
|
static void
|
|
l2arc_dev_rebuild_thread(void *arg)
|
|
{
|
|
l2arc_dev_t *dev = arg;
|
|
|
|
VERIFY(!dev->l2ad_rebuild_cancel);
|
|
VERIFY(dev->l2ad_rebuild);
|
|
(void) l2arc_rebuild(dev);
|
|
mutex_enter(&l2arc_rebuild_thr_lock);
|
|
dev->l2ad_rebuild_began = B_FALSE;
|
|
dev->l2ad_rebuild = B_FALSE;
|
|
mutex_exit(&l2arc_rebuild_thr_lock);
|
|
|
|
thread_exit();
|
|
}
|
|
|
|
/*
|
|
* This function implements the actual L2ARC metadata rebuild. It:
|
|
* starts reading the log block chain and restores each block's contents
|
|
* to memory (reconstructing arc_buf_hdr_t's).
|
|
*
|
|
* Operation stops under any of the following conditions:
|
|
*
|
|
* 1) We reach the end of the log block chain.
|
|
* 2) We encounter *any* error condition (cksum errors, io errors)
|
|
*/
|
|
static int
|
|
l2arc_rebuild(l2arc_dev_t *dev)
|
|
{
|
|
vdev_t *vd = dev->l2ad_vdev;
|
|
spa_t *spa = vd->vdev_spa;
|
|
int err = 0;
|
|
l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr;
|
|
l2arc_log_blk_phys_t *this_lb, *next_lb;
|
|
zio_t *this_io = NULL, *next_io = NULL;
|
|
l2arc_log_blkptr_t lbps[2];
|
|
l2arc_lb_ptr_buf_t *lb_ptr_buf;
|
|
boolean_t lock_held;
|
|
|
|
this_lb = vmem_zalloc(sizeof (*this_lb), KM_SLEEP);
|
|
next_lb = vmem_zalloc(sizeof (*next_lb), KM_SLEEP);
|
|
|
|
/*
|
|
* We prevent device removal while issuing reads to the device,
|
|
* then during the rebuilding phases we drop this lock again so
|
|
* that a spa_unload or device remove can be initiated - this is
|
|
* safe, because the spa will signal us to stop before removing
|
|
* our device and wait for us to stop.
|
|
*/
|
|
spa_config_enter(spa, SCL_L2ARC, vd, RW_READER);
|
|
lock_held = B_TRUE;
|
|
|
|
/*
|
|
* Retrieve the persistent L2ARC device state.
|
|
* L2BLK_GET_PSIZE returns aligned size for log blocks.
|
|
*/
|
|
dev->l2ad_evict = MAX(l2dhdr->dh_evict, dev->l2ad_start);
|
|
dev->l2ad_hand = MAX(l2dhdr->dh_start_lbps[0].lbp_daddr +
|
|
L2BLK_GET_PSIZE((&l2dhdr->dh_start_lbps[0])->lbp_prop),
|
|
dev->l2ad_start);
|
|
dev->l2ad_first = !!(l2dhdr->dh_flags & L2ARC_DEV_HDR_EVICT_FIRST);
|
|
|
|
vd->vdev_trim_action_time = l2dhdr->dh_trim_action_time;
|
|
vd->vdev_trim_state = l2dhdr->dh_trim_state;
|
|
|
|
/*
|
|
* In case the zfs module parameter l2arc_rebuild_enabled is false
|
|
* we do not start the rebuild process.
|
|
*/
|
|
if (!l2arc_rebuild_enabled)
|
|
goto out;
|
|
|
|
/* Prepare the rebuild process */
|
|
bcopy(l2dhdr->dh_start_lbps, lbps, sizeof (lbps));
|
|
|
|
/* Start the rebuild process */
|
|
for (;;) {
|
|
if (!l2arc_log_blkptr_valid(dev, &lbps[0]))
|
|
break;
|
|
|
|
if ((err = l2arc_log_blk_read(dev, &lbps[0], &lbps[1],
|
|
this_lb, next_lb, this_io, &next_io)) != 0)
|
|
goto out;
|
|
|
|
/*
|
|
* Our memory pressure valve. If the system is running low
|
|
* on memory, rather than swamping memory with new ARC buf
|
|
* hdrs, we opt not to rebuild the L2ARC. At this point,
|
|
* however, we have already set up our L2ARC dev to chain in
|
|
* new metadata log blocks, so the user may choose to offline/
|
|
* online the L2ARC dev at a later time (or re-import the pool)
|
|
* to reconstruct it (when there's less memory pressure).
|
|
*/
|
|
if (l2arc_hdr_limit_reached()) {
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_abort_lowmem);
|
|
cmn_err(CE_NOTE, "System running low on memory, "
|
|
"aborting L2ARC rebuild.");
|
|
err = SET_ERROR(ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
lock_held = B_FALSE;
|
|
|
|
/*
|
|
* Now that we know that the next_lb checks out alright, we
|
|
* can start reconstruction from this log block.
|
|
* L2BLK_GET_PSIZE returns aligned size for log blocks.
|
|
*/
|
|
uint64_t asize = L2BLK_GET_PSIZE((&lbps[0])->lbp_prop);
|
|
l2arc_log_blk_restore(dev, this_lb, asize, lbps[0].lbp_daddr);
|
|
|
|
/*
|
|
* log block restored, include its pointer in the list of
|
|
* pointers to log blocks present in the L2ARC device.
|
|
*/
|
|
lb_ptr_buf = kmem_zalloc(sizeof (l2arc_lb_ptr_buf_t), KM_SLEEP);
|
|
lb_ptr_buf->lb_ptr = kmem_zalloc(sizeof (l2arc_log_blkptr_t),
|
|
KM_SLEEP);
|
|
bcopy(&lbps[0], lb_ptr_buf->lb_ptr,
|
|
sizeof (l2arc_log_blkptr_t));
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_tail(&dev->l2ad_lbptr_list, lb_ptr_buf);
|
|
ARCSTAT_INCR(arcstat_l2_log_blk_asize, asize);
|
|
ARCSTAT_BUMP(arcstat_l2_log_blk_count);
|
|
zfs_refcount_add_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf);
|
|
zfs_refcount_add(&dev->l2ad_lb_count, lb_ptr_buf);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
vdev_space_update(vd, asize, 0, 0);
|
|
|
|
/*
|
|
* Protection against loops of log blocks:
|
|
*
|
|
* l2ad_hand l2ad_evict
|
|
* V V
|
|
* l2ad_start |=======================================| l2ad_end
|
|
* -----|||----|||---|||----|||
|
|
* (3) (2) (1) (0)
|
|
* ---|||---|||----|||---|||
|
|
* (7) (6) (5) (4)
|
|
*
|
|
* In this situation the pointer of log block (4) passes
|
|
* l2arc_log_blkptr_valid() but the log block should not be
|
|
* restored as it is overwritten by the payload of log block
|
|
* (0). Only log blocks (0)-(3) should be restored. We check
|
|
* whether l2ad_evict lies in between the payload starting
|
|
* offset of the next log block (lbps[1].lbp_payload_start)
|
|
* and the payload starting offset of the present log block
|
|
* (lbps[0].lbp_payload_start). If true and this isn't the
|
|
* first pass, we are looping from the beginning and we should
|
|
* stop.
|
|
*/
|
|
if (l2arc_range_check_overlap(lbps[1].lbp_payload_start,
|
|
lbps[0].lbp_payload_start, dev->l2ad_evict) &&
|
|
!dev->l2ad_first)
|
|
goto out;
|
|
|
|
for (;;) {
|
|
mutex_enter(&l2arc_rebuild_thr_lock);
|
|
if (dev->l2ad_rebuild_cancel) {
|
|
dev->l2ad_rebuild = B_FALSE;
|
|
cv_signal(&l2arc_rebuild_thr_cv);
|
|
mutex_exit(&l2arc_rebuild_thr_lock);
|
|
err = SET_ERROR(ECANCELED);
|
|
goto out;
|
|
}
|
|
mutex_exit(&l2arc_rebuild_thr_lock);
|
|
if (spa_config_tryenter(spa, SCL_L2ARC, vd,
|
|
RW_READER)) {
|
|
lock_held = B_TRUE;
|
|
break;
|
|
}
|
|
/*
|
|
* L2ARC config lock held by somebody in writer,
|
|
* possibly due to them trying to remove us. They'll
|
|
* likely to want us to shut down, so after a little
|
|
* delay, we check l2ad_rebuild_cancel and retry
|
|
* the lock again.
|
|
*/
|
|
delay(1);
|
|
}
|
|
|
|
/*
|
|
* Continue with the next log block.
|
|
*/
|
|
lbps[0] = lbps[1];
|
|
lbps[1] = this_lb->lb_prev_lbp;
|
|
PTR_SWAP(this_lb, next_lb);
|
|
this_io = next_io;
|
|
next_io = NULL;
|
|
}
|
|
|
|
if (this_io != NULL)
|
|
l2arc_log_blk_fetch_abort(this_io);
|
|
out:
|
|
if (next_io != NULL)
|
|
l2arc_log_blk_fetch_abort(next_io);
|
|
vmem_free(this_lb, sizeof (*this_lb));
|
|
vmem_free(next_lb, sizeof (*next_lb));
|
|
|
|
if (!l2arc_rebuild_enabled) {
|
|
spa_history_log_internal(spa, "L2ARC rebuild", NULL,
|
|
"disabled");
|
|
} else if (err == 0 && zfs_refcount_count(&dev->l2ad_lb_count) > 0) {
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_success);
|
|
spa_history_log_internal(spa, "L2ARC rebuild", NULL,
|
|
"successful, restored %llu blocks",
|
|
(u_longlong_t)zfs_refcount_count(&dev->l2ad_lb_count));
|
|
} else if (err == 0 && zfs_refcount_count(&dev->l2ad_lb_count) == 0) {
|
|
/*
|
|
* No error but also nothing restored, meaning the lbps array
|
|
* in the device header points to invalid/non-present log
|
|
* blocks. Reset the header.
|
|
*/
|
|
spa_history_log_internal(spa, "L2ARC rebuild", NULL,
|
|
"no valid log blocks");
|
|
bzero(l2dhdr, dev->l2ad_dev_hdr_asize);
|
|
l2arc_dev_hdr_update(dev);
|
|
} else if (err == ECANCELED) {
|
|
/*
|
|
* In case the rebuild was canceled do not log to spa history
|
|
* log as the pool may be in the process of being removed.
|
|
*/
|
|
zfs_dbgmsg("L2ARC rebuild aborted, restored %llu blocks",
|
|
zfs_refcount_count(&dev->l2ad_lb_count));
|
|
} else if (err != 0) {
|
|
spa_history_log_internal(spa, "L2ARC rebuild", NULL,
|
|
"aborted, restored %llu blocks",
|
|
(u_longlong_t)zfs_refcount_count(&dev->l2ad_lb_count));
|
|
}
|
|
|
|
if (lock_held)
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
|
|
return (err);
|
|
}
|
|
|
|
/*
|
|
* Attempts to read the device header on the provided L2ARC device and writes
|
|
* it to `hdr'. On success, this function returns 0, otherwise the appropriate
|
|
* error code is returned.
|
|
*/
|
|
static int
|
|
l2arc_dev_hdr_read(l2arc_dev_t *dev)
|
|
{
|
|
int err;
|
|
uint64_t guid;
|
|
l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr;
|
|
const uint64_t l2dhdr_asize = dev->l2ad_dev_hdr_asize;
|
|
abd_t *abd;
|
|
|
|
guid = spa_guid(dev->l2ad_vdev->vdev_spa);
|
|
|
|
abd = abd_get_from_buf(l2dhdr, l2dhdr_asize);
|
|
|
|
err = zio_wait(zio_read_phys(NULL, dev->l2ad_vdev,
|
|
VDEV_LABEL_START_SIZE, l2dhdr_asize, abd,
|
|
ZIO_CHECKSUM_LABEL, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
|
|
ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL |
|
|
ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY |
|
|
ZIO_FLAG_SPECULATIVE, B_FALSE));
|
|
|
|
abd_put(abd);
|
|
|
|
if (err != 0) {
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_abort_dh_errors);
|
|
zfs_dbgmsg("L2ARC IO error (%d) while reading device header, "
|
|
"vdev guid: %llu", err, dev->l2ad_vdev->vdev_guid);
|
|
return (err);
|
|
}
|
|
|
|
if (l2dhdr->dh_magic == BSWAP_64(L2ARC_DEV_HDR_MAGIC))
|
|
byteswap_uint64_array(l2dhdr, sizeof (*l2dhdr));
|
|
|
|
if (l2dhdr->dh_magic != L2ARC_DEV_HDR_MAGIC ||
|
|
l2dhdr->dh_spa_guid != guid ||
|
|
l2dhdr->dh_vdev_guid != dev->l2ad_vdev->vdev_guid ||
|
|
l2dhdr->dh_version != L2ARC_PERSISTENT_VERSION ||
|
|
l2dhdr->dh_log_entries != dev->l2ad_log_entries ||
|
|
l2dhdr->dh_end != dev->l2ad_end ||
|
|
!l2arc_range_check_overlap(dev->l2ad_start, dev->l2ad_end,
|
|
l2dhdr->dh_evict) ||
|
|
(l2dhdr->dh_trim_state != VDEV_TRIM_COMPLETE &&
|
|
l2arc_trim_ahead > 0)) {
|
|
/*
|
|
* Attempt to rebuild a device containing no actual dev hdr
|
|
* or containing a header from some other pool or from another
|
|
* version of persistent L2ARC.
|
|
*/
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_abort_unsupported);
|
|
return (SET_ERROR(ENOTSUP));
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Reads L2ARC log blocks from storage and validates their contents.
|
|
*
|
|
* This function implements a simple fetcher to make sure that while
|
|
* we're processing one buffer the L2ARC is already fetching the next
|
|
* one in the chain.
|
|
*
|
|
* The arguments this_lp and next_lp point to the current and next log block
|
|
* address in the block chain. Similarly, this_lb and next_lb hold the
|
|
* l2arc_log_blk_phys_t's of the current and next L2ARC blk.
|
|
*
|
|
* The `this_io' and `next_io' arguments are used for block fetching.
|
|
* When issuing the first blk IO during rebuild, you should pass NULL for
|
|
* `this_io'. This function will then issue a sync IO to read the block and
|
|
* also issue an async IO to fetch the next block in the block chain. The
|
|
* fetched IO is returned in `next_io'. On subsequent calls to this
|
|
* function, pass the value returned in `next_io' from the previous call
|
|
* as `this_io' and a fresh `next_io' pointer to hold the next fetch IO.
|
|
* Prior to the call, you should initialize your `next_io' pointer to be
|
|
* NULL. If no fetch IO was issued, the pointer is left set at NULL.
|
|
*
|
|
* On success, this function returns 0, otherwise it returns an appropriate
|
|
* error code. On error the fetching IO is aborted and cleared before
|
|
* returning from this function. Therefore, if we return `success', the
|
|
* caller can assume that we have taken care of cleanup of fetch IOs.
|
|
*/
|
|
static int
|
|
l2arc_log_blk_read(l2arc_dev_t *dev,
|
|
const l2arc_log_blkptr_t *this_lbp, const l2arc_log_blkptr_t *next_lbp,
|
|
l2arc_log_blk_phys_t *this_lb, l2arc_log_blk_phys_t *next_lb,
|
|
zio_t *this_io, zio_t **next_io)
|
|
{
|
|
int err = 0;
|
|
zio_cksum_t cksum;
|
|
abd_t *abd = NULL;
|
|
uint64_t asize;
|
|
|
|
ASSERT(this_lbp != NULL && next_lbp != NULL);
|
|
ASSERT(this_lb != NULL && next_lb != NULL);
|
|
ASSERT(next_io != NULL && *next_io == NULL);
|
|
ASSERT(l2arc_log_blkptr_valid(dev, this_lbp));
|
|
|
|
/*
|
|
* Check to see if we have issued the IO for this log block in a
|
|
* previous run. If not, this is the first call, so issue it now.
|
|
*/
|
|
if (this_io == NULL) {
|
|
this_io = l2arc_log_blk_fetch(dev->l2ad_vdev, this_lbp,
|
|
this_lb);
|
|
}
|
|
|
|
/*
|
|
* Peek to see if we can start issuing the next IO immediately.
|
|
*/
|
|
if (l2arc_log_blkptr_valid(dev, next_lbp)) {
|
|
/*
|
|
* Start issuing IO for the next log block early - this
|
|
* should help keep the L2ARC device busy while we
|
|
* decompress and restore this log block.
|
|
*/
|
|
*next_io = l2arc_log_blk_fetch(dev->l2ad_vdev, next_lbp,
|
|
next_lb);
|
|
}
|
|
|
|
/* Wait for the IO to read this log block to complete */
|
|
if ((err = zio_wait(this_io)) != 0) {
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_abort_io_errors);
|
|
zfs_dbgmsg("L2ARC IO error (%d) while reading log block, "
|
|
"offset: %llu, vdev guid: %llu", err, this_lbp->lbp_daddr,
|
|
dev->l2ad_vdev->vdev_guid);
|
|
goto cleanup;
|
|
}
|
|
|
|
/*
|
|
* Make sure the buffer checks out.
|
|
* L2BLK_GET_PSIZE returns aligned size for log blocks.
|
|
*/
|
|
asize = L2BLK_GET_PSIZE((this_lbp)->lbp_prop);
|
|
fletcher_4_native(this_lb, asize, NULL, &cksum);
|
|
if (!ZIO_CHECKSUM_EQUAL(cksum, this_lbp->lbp_cksum)) {
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_abort_cksum_lb_errors);
|
|
zfs_dbgmsg("L2ARC log block cksum failed, offset: %llu, "
|
|
"vdev guid: %llu, l2ad_hand: %llu, l2ad_evict: %llu",
|
|
this_lbp->lbp_daddr, dev->l2ad_vdev->vdev_guid,
|
|
dev->l2ad_hand, dev->l2ad_evict);
|
|
err = SET_ERROR(ECKSUM);
|
|
goto cleanup;
|
|
}
|
|
|
|
/* Now we can take our time decoding this buffer */
|
|
switch (L2BLK_GET_COMPRESS((this_lbp)->lbp_prop)) {
|
|
case ZIO_COMPRESS_OFF:
|
|
break;
|
|
case ZIO_COMPRESS_LZ4:
|
|
abd = abd_alloc_for_io(asize, B_TRUE);
|
|
abd_copy_from_buf_off(abd, this_lb, 0, asize);
|
|
if ((err = zio_decompress_data(
|
|
L2BLK_GET_COMPRESS((this_lbp)->lbp_prop),
|
|
abd, this_lb, asize, sizeof (*this_lb), NULL)) != 0) {
|
|
err = SET_ERROR(EINVAL);
|
|
goto cleanup;
|
|
}
|
|
break;
|
|
default:
|
|
err = SET_ERROR(EINVAL);
|
|
goto cleanup;
|
|
}
|
|
if (this_lb->lb_magic == BSWAP_64(L2ARC_LOG_BLK_MAGIC))
|
|
byteswap_uint64_array(this_lb, sizeof (*this_lb));
|
|
if (this_lb->lb_magic != L2ARC_LOG_BLK_MAGIC) {
|
|
err = SET_ERROR(EINVAL);
|
|
goto cleanup;
|
|
}
|
|
cleanup:
|
|
/* Abort an in-flight fetch I/O in case of error */
|
|
if (err != 0 && *next_io != NULL) {
|
|
l2arc_log_blk_fetch_abort(*next_io);
|
|
*next_io = NULL;
|
|
}
|
|
if (abd != NULL)
|
|
abd_free(abd);
|
|
return (err);
|
|
}
|
|
|
|
/*
|
|
* Restores the payload of a log block to ARC. This creates empty ARC hdr
|
|
* entries which only contain an l2arc hdr, essentially restoring the
|
|
* buffers to their L2ARC evicted state. This function also updates space
|
|
* usage on the L2ARC vdev to make sure it tracks restored buffers.
|
|
*/
|
|
static void
|
|
l2arc_log_blk_restore(l2arc_dev_t *dev, const l2arc_log_blk_phys_t *lb,
|
|
uint64_t lb_asize, uint64_t lb_daddr)
|
|
{
|
|
uint64_t size = 0, asize = 0;
|
|
uint64_t log_entries = dev->l2ad_log_entries;
|
|
|
|
/*
|
|
* Usually arc_adapt() is called only for data, not headers, but
|
|
* since we may allocate significant amount of memory here, let ARC
|
|
* grow its arc_c.
|
|
*/
|
|
arc_adapt(log_entries * HDR_L2ONLY_SIZE, arc_l2c_only);
|
|
|
|
for (int i = log_entries - 1; i >= 0; i--) {
|
|
/*
|
|
* Restore goes in the reverse temporal direction to preserve
|
|
* correct temporal ordering of buffers in the l2ad_buflist.
|
|
* l2arc_hdr_restore also does a list_insert_tail instead of
|
|
* list_insert_head on the l2ad_buflist:
|
|
*
|
|
* LIST l2ad_buflist LIST
|
|
* HEAD <------ (time) ------ TAIL
|
|
* direction +-----+-----+-----+-----+-----+ direction
|
|
* of l2arc <== | buf | buf | buf | buf | buf | ===> of rebuild
|
|
* fill +-----+-----+-----+-----+-----+
|
|
* ^ ^
|
|
* | |
|
|
* | |
|
|
* l2arc_feed_thread l2arc_rebuild
|
|
* will place new bufs here restores bufs here
|
|
*
|
|
* During l2arc_rebuild() the device is not used by
|
|
* l2arc_feed_thread() as dev->l2ad_rebuild is set to true.
|
|
*/
|
|
size += L2BLK_GET_LSIZE((&lb->lb_entries[i])->le_prop);
|
|
asize += vdev_psize_to_asize(dev->l2ad_vdev,
|
|
L2BLK_GET_PSIZE((&lb->lb_entries[i])->le_prop));
|
|
l2arc_hdr_restore(&lb->lb_entries[i], dev);
|
|
}
|
|
|
|
/*
|
|
* Record rebuild stats:
|
|
* size Logical size of restored buffers in the L2ARC
|
|
* asize Aligned size of restored buffers in the L2ARC
|
|
*/
|
|
ARCSTAT_INCR(arcstat_l2_rebuild_size, size);
|
|
ARCSTAT_INCR(arcstat_l2_rebuild_asize, asize);
|
|
ARCSTAT_INCR(arcstat_l2_rebuild_bufs, log_entries);
|
|
ARCSTAT_F_AVG(arcstat_l2_log_blk_avg_asize, lb_asize);
|
|
ARCSTAT_F_AVG(arcstat_l2_data_to_meta_ratio, asize / lb_asize);
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_log_blks);
|
|
}
|
|
|
|
/*
|
|
* Restores a single ARC buf hdr from a log entry. The ARC buffer is put
|
|
* into a state indicating that it has been evicted to L2ARC.
|
|
*/
|
|
static void
|
|
l2arc_hdr_restore(const l2arc_log_ent_phys_t *le, l2arc_dev_t *dev)
|
|
{
|
|
arc_buf_hdr_t *hdr, *exists;
|
|
kmutex_t *hash_lock;
|
|
arc_buf_contents_t type = L2BLK_GET_TYPE((le)->le_prop);
|
|
uint64_t asize;
|
|
|
|
/*
|
|
* Do all the allocation before grabbing any locks, this lets us
|
|
* sleep if memory is full and we don't have to deal with failed
|
|
* allocations.
|
|
*/
|
|
hdr = arc_buf_alloc_l2only(L2BLK_GET_LSIZE((le)->le_prop), type,
|
|
dev, le->le_dva, le->le_daddr,
|
|
L2BLK_GET_PSIZE((le)->le_prop), le->le_birth,
|
|
L2BLK_GET_COMPRESS((le)->le_prop), le->le_complevel,
|
|
L2BLK_GET_PROTECTED((le)->le_prop),
|
|
L2BLK_GET_PREFETCH((le)->le_prop));
|
|
asize = vdev_psize_to_asize(dev->l2ad_vdev,
|
|
L2BLK_GET_PSIZE((le)->le_prop));
|
|
|
|
/*
|
|
* vdev_space_update() has to be called before arc_hdr_destroy() to
|
|
* avoid underflow since the latter also calls the former.
|
|
*/
|
|
vdev_space_update(dev->l2ad_vdev, asize, 0, 0);
|
|
|
|
ARCSTAT_INCR(arcstat_l2_lsize, HDR_GET_LSIZE(hdr));
|
|
ARCSTAT_INCR(arcstat_l2_psize, HDR_GET_PSIZE(hdr));
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_tail(&dev->l2ad_buflist, hdr);
|
|
(void) zfs_refcount_add_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
if (exists) {
|
|
/* Buffer was already cached, no need to restore it. */
|
|
arc_hdr_destroy(hdr);
|
|
/*
|
|
* If the buffer is already cached, check whether it has
|
|
* L2ARC metadata. If not, enter them and update the flag.
|
|
* This is important is case of onlining a cache device, since
|
|
* we previously evicted all L2ARC metadata from ARC.
|
|
*/
|
|
if (!HDR_HAS_L2HDR(exists)) {
|
|
arc_hdr_set_flags(exists, ARC_FLAG_HAS_L2HDR);
|
|
exists->b_l2hdr.b_dev = dev;
|
|
exists->b_l2hdr.b_daddr = le->le_daddr;
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_tail(&dev->l2ad_buflist, exists);
|
|
(void) zfs_refcount_add_many(&dev->l2ad_alloc,
|
|
arc_hdr_size(exists), exists);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
vdev_space_update(dev->l2ad_vdev, asize, 0, 0);
|
|
ARCSTAT_INCR(arcstat_l2_lsize, HDR_GET_LSIZE(exists));
|
|
ARCSTAT_INCR(arcstat_l2_psize, HDR_GET_PSIZE(exists));
|
|
}
|
|
ARCSTAT_BUMP(arcstat_l2_rebuild_bufs_precached);
|
|
}
|
|
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
/*
|
|
* Starts an asynchronous read IO to read a log block. This is used in log
|
|
* block reconstruction to start reading the next block before we are done
|
|
* decoding and reconstructing the current block, to keep the l2arc device
|
|
* nice and hot with read IO to process.
|
|
* The returned zio will contain a newly allocated memory buffers for the IO
|
|
* data which should then be freed by the caller once the zio is no longer
|
|
* needed (i.e. due to it having completed). If you wish to abort this
|
|
* zio, you should do so using l2arc_log_blk_fetch_abort, which takes
|
|
* care of disposing of the allocated buffers correctly.
|
|
*/
|
|
static zio_t *
|
|
l2arc_log_blk_fetch(vdev_t *vd, const l2arc_log_blkptr_t *lbp,
|
|
l2arc_log_blk_phys_t *lb)
|
|
{
|
|
uint32_t asize;
|
|
zio_t *pio;
|
|
l2arc_read_callback_t *cb;
|
|
|
|
/* L2BLK_GET_PSIZE returns aligned size for log blocks */
|
|
asize = L2BLK_GET_PSIZE((lbp)->lbp_prop);
|
|
ASSERT(asize <= sizeof (l2arc_log_blk_phys_t));
|
|
|
|
cb = kmem_zalloc(sizeof (l2arc_read_callback_t), KM_SLEEP);
|
|
cb->l2rcb_abd = abd_get_from_buf(lb, asize);
|
|
pio = zio_root(vd->vdev_spa, l2arc_blk_fetch_done, cb,
|
|
ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE |
|
|
ZIO_FLAG_DONT_RETRY);
|
|
(void) zio_nowait(zio_read_phys(pio, vd, lbp->lbp_daddr, asize,
|
|
cb->l2rcb_abd, ZIO_CHECKSUM_OFF, NULL, NULL,
|
|
ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL |
|
|
ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY, B_FALSE));
|
|
|
|
return (pio);
|
|
}
|
|
|
|
/*
|
|
* Aborts a zio returned from l2arc_log_blk_fetch and frees the data
|
|
* buffers allocated for it.
|
|
*/
|
|
static void
|
|
l2arc_log_blk_fetch_abort(zio_t *zio)
|
|
{
|
|
(void) zio_wait(zio);
|
|
}
|
|
|
|
/*
|
|
* Creates a zio to update the device header on an l2arc device.
|
|
*/
|
|
void
|
|
l2arc_dev_hdr_update(l2arc_dev_t *dev)
|
|
{
|
|
l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr;
|
|
const uint64_t l2dhdr_asize = dev->l2ad_dev_hdr_asize;
|
|
abd_t *abd;
|
|
int err;
|
|
|
|
VERIFY(spa_config_held(dev->l2ad_spa, SCL_STATE_ALL, RW_READER));
|
|
|
|
l2dhdr->dh_magic = L2ARC_DEV_HDR_MAGIC;
|
|
l2dhdr->dh_version = L2ARC_PERSISTENT_VERSION;
|
|
l2dhdr->dh_spa_guid = spa_guid(dev->l2ad_vdev->vdev_spa);
|
|
l2dhdr->dh_vdev_guid = dev->l2ad_vdev->vdev_guid;
|
|
l2dhdr->dh_log_entries = dev->l2ad_log_entries;
|
|
l2dhdr->dh_evict = dev->l2ad_evict;
|
|
l2dhdr->dh_start = dev->l2ad_start;
|
|
l2dhdr->dh_end = dev->l2ad_end;
|
|
l2dhdr->dh_lb_asize = zfs_refcount_count(&dev->l2ad_lb_asize);
|
|
l2dhdr->dh_lb_count = zfs_refcount_count(&dev->l2ad_lb_count);
|
|
l2dhdr->dh_flags = 0;
|
|
l2dhdr->dh_trim_action_time = dev->l2ad_vdev->vdev_trim_action_time;
|
|
l2dhdr->dh_trim_state = dev->l2ad_vdev->vdev_trim_state;
|
|
if (dev->l2ad_first)
|
|
l2dhdr->dh_flags |= L2ARC_DEV_HDR_EVICT_FIRST;
|
|
|
|
abd = abd_get_from_buf(l2dhdr, l2dhdr_asize);
|
|
|
|
err = zio_wait(zio_write_phys(NULL, dev->l2ad_vdev,
|
|
VDEV_LABEL_START_SIZE, l2dhdr_asize, abd, ZIO_CHECKSUM_LABEL, NULL,
|
|
NULL, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_CANFAIL, B_FALSE));
|
|
|
|
abd_put(abd);
|
|
|
|
if (err != 0) {
|
|
zfs_dbgmsg("L2ARC IO error (%d) while writing device header, "
|
|
"vdev guid: %llu", err, dev->l2ad_vdev->vdev_guid);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Commits a log block to the L2ARC device. This routine is invoked from
|
|
* l2arc_write_buffers when the log block fills up.
|
|
* This function allocates some memory to temporarily hold the serialized
|
|
* buffer to be written. This is then released in l2arc_write_done.
|
|
*/
|
|
static void
|
|
l2arc_log_blk_commit(l2arc_dev_t *dev, zio_t *pio, l2arc_write_callback_t *cb)
|
|
{
|
|
l2arc_log_blk_phys_t *lb = &dev->l2ad_log_blk;
|
|
l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr;
|
|
uint64_t psize, asize;
|
|
zio_t *wzio;
|
|
l2arc_lb_abd_buf_t *abd_buf;
|
|
uint8_t *tmpbuf;
|
|
l2arc_lb_ptr_buf_t *lb_ptr_buf;
|
|
|
|
VERIFY3S(dev->l2ad_log_ent_idx, ==, dev->l2ad_log_entries);
|
|
|
|
tmpbuf = zio_buf_alloc(sizeof (*lb));
|
|
abd_buf = zio_buf_alloc(sizeof (*abd_buf));
|
|
abd_buf->abd = abd_get_from_buf(lb, sizeof (*lb));
|
|
lb_ptr_buf = kmem_zalloc(sizeof (l2arc_lb_ptr_buf_t), KM_SLEEP);
|
|
lb_ptr_buf->lb_ptr = kmem_zalloc(sizeof (l2arc_log_blkptr_t), KM_SLEEP);
|
|
|
|
/* link the buffer into the block chain */
|
|
lb->lb_prev_lbp = l2dhdr->dh_start_lbps[1];
|
|
lb->lb_magic = L2ARC_LOG_BLK_MAGIC;
|
|
|
|
/*
|
|
* l2arc_log_blk_commit() may be called multiple times during a single
|
|
* l2arc_write_buffers() call. Save the allocated abd buffers in a list
|
|
* so we can free them in l2arc_write_done() later on.
|
|
*/
|
|
list_insert_tail(&cb->l2wcb_abd_list, abd_buf);
|
|
|
|
/* try to compress the buffer */
|
|
psize = zio_compress_data(ZIO_COMPRESS_LZ4,
|
|
abd_buf->abd, tmpbuf, sizeof (*lb), 0);
|
|
|
|
/* a log block is never entirely zero */
|
|
ASSERT(psize != 0);
|
|
asize = vdev_psize_to_asize(dev->l2ad_vdev, psize);
|
|
ASSERT(asize <= sizeof (*lb));
|
|
|
|
/*
|
|
* Update the start log block pointer in the device header to point
|
|
* to the log block we're about to write.
|
|
*/
|
|
l2dhdr->dh_start_lbps[1] = l2dhdr->dh_start_lbps[0];
|
|
l2dhdr->dh_start_lbps[0].lbp_daddr = dev->l2ad_hand;
|
|
l2dhdr->dh_start_lbps[0].lbp_payload_asize =
|
|
dev->l2ad_log_blk_payload_asize;
|
|
l2dhdr->dh_start_lbps[0].lbp_payload_start =
|
|
dev->l2ad_log_blk_payload_start;
|
|
_NOTE(CONSTCOND)
|
|
L2BLK_SET_LSIZE(
|
|
(&l2dhdr->dh_start_lbps[0])->lbp_prop, sizeof (*lb));
|
|
L2BLK_SET_PSIZE(
|
|
(&l2dhdr->dh_start_lbps[0])->lbp_prop, asize);
|
|
L2BLK_SET_CHECKSUM(
|
|
(&l2dhdr->dh_start_lbps[0])->lbp_prop,
|
|
ZIO_CHECKSUM_FLETCHER_4);
|
|
if (asize < sizeof (*lb)) {
|
|
/* compression succeeded */
|
|
bzero(tmpbuf + psize, asize - psize);
|
|
L2BLK_SET_COMPRESS(
|
|
(&l2dhdr->dh_start_lbps[0])->lbp_prop,
|
|
ZIO_COMPRESS_LZ4);
|
|
} else {
|
|
/* compression failed */
|
|
bcopy(lb, tmpbuf, sizeof (*lb));
|
|
L2BLK_SET_COMPRESS(
|
|
(&l2dhdr->dh_start_lbps[0])->lbp_prop,
|
|
ZIO_COMPRESS_OFF);
|
|
}
|
|
|
|
/* checksum what we're about to write */
|
|
fletcher_4_native(tmpbuf, asize, NULL,
|
|
&l2dhdr->dh_start_lbps[0].lbp_cksum);
|
|
|
|
abd_put(abd_buf->abd);
|
|
|
|
/* perform the write itself */
|
|
abd_buf->abd = abd_get_from_buf(tmpbuf, sizeof (*lb));
|
|
abd_take_ownership_of_buf(abd_buf->abd, B_TRUE);
|
|
wzio = zio_write_phys(pio, dev->l2ad_vdev, dev->l2ad_hand,
|
|
asize, abd_buf->abd, ZIO_CHECKSUM_OFF, NULL, NULL,
|
|
ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_CANFAIL, B_FALSE);
|
|
DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, zio_t *, wzio);
|
|
(void) zio_nowait(wzio);
|
|
|
|
dev->l2ad_hand += asize;
|
|
/*
|
|
* Include the committed log block's pointer in the list of pointers
|
|
* to log blocks present in the L2ARC device.
|
|
*/
|
|
bcopy(&l2dhdr->dh_start_lbps[0], lb_ptr_buf->lb_ptr,
|
|
sizeof (l2arc_log_blkptr_t));
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_head(&dev->l2ad_lbptr_list, lb_ptr_buf);
|
|
ARCSTAT_INCR(arcstat_l2_log_blk_asize, asize);
|
|
ARCSTAT_BUMP(arcstat_l2_log_blk_count);
|
|
zfs_refcount_add_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf);
|
|
zfs_refcount_add(&dev->l2ad_lb_count, lb_ptr_buf);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
vdev_space_update(dev->l2ad_vdev, asize, 0, 0);
|
|
|
|
/* bump the kstats */
|
|
ARCSTAT_INCR(arcstat_l2_write_bytes, asize);
|
|
ARCSTAT_BUMP(arcstat_l2_log_blk_writes);
|
|
ARCSTAT_F_AVG(arcstat_l2_log_blk_avg_asize, asize);
|
|
ARCSTAT_F_AVG(arcstat_l2_data_to_meta_ratio,
|
|
dev->l2ad_log_blk_payload_asize / asize);
|
|
|
|
/* start a new log block */
|
|
dev->l2ad_log_ent_idx = 0;
|
|
dev->l2ad_log_blk_payload_asize = 0;
|
|
dev->l2ad_log_blk_payload_start = 0;
|
|
}
|
|
|
|
/*
|
|
* Validates an L2ARC log block address to make sure that it can be read
|
|
* from the provided L2ARC device.
|
|
*/
|
|
boolean_t
|
|
l2arc_log_blkptr_valid(l2arc_dev_t *dev, const l2arc_log_blkptr_t *lbp)
|
|
{
|
|
/* L2BLK_GET_PSIZE returns aligned size for log blocks */
|
|
uint64_t asize = L2BLK_GET_PSIZE((lbp)->lbp_prop);
|
|
uint64_t end = lbp->lbp_daddr + asize - 1;
|
|
uint64_t start = lbp->lbp_payload_start;
|
|
boolean_t evicted = B_FALSE;
|
|
|
|
/*
|
|
* A log block is valid if all of the following conditions are true:
|
|
* - it fits entirely (including its payload) between l2ad_start and
|
|
* l2ad_end
|
|
* - it has a valid size
|
|
* - neither the log block itself nor part of its payload was evicted
|
|
* by l2arc_evict():
|
|
*
|
|
* l2ad_hand l2ad_evict
|
|
* | | lbp_daddr
|
|
* | start | | end
|
|
* | | | | |
|
|
* V V V V V
|
|
* l2ad_start ============================================ l2ad_end
|
|
* --------------------------||||
|
|
* ^ ^
|
|
* | log block
|
|
* payload
|
|
*/
|
|
|
|
evicted =
|
|
l2arc_range_check_overlap(start, end, dev->l2ad_hand) ||
|
|
l2arc_range_check_overlap(start, end, dev->l2ad_evict) ||
|
|
l2arc_range_check_overlap(dev->l2ad_hand, dev->l2ad_evict, start) ||
|
|
l2arc_range_check_overlap(dev->l2ad_hand, dev->l2ad_evict, end);
|
|
|
|
return (start >= dev->l2ad_start && end <= dev->l2ad_end &&
|
|
asize > 0 && asize <= sizeof (l2arc_log_blk_phys_t) &&
|
|
(!evicted || dev->l2ad_first));
|
|
}
|
|
|
|
/*
|
|
* Inserts ARC buffer header `hdr' into the current L2ARC log block on
|
|
* the device. The buffer being inserted must be present in L2ARC.
|
|
* Returns B_TRUE if the L2ARC log block is full and needs to be committed
|
|
* to L2ARC, or B_FALSE if it still has room for more ARC buffers.
|
|
*/
|
|
static boolean_t
|
|
l2arc_log_blk_insert(l2arc_dev_t *dev, const arc_buf_hdr_t *hdr)
|
|
{
|
|
l2arc_log_blk_phys_t *lb = &dev->l2ad_log_blk;
|
|
l2arc_log_ent_phys_t *le;
|
|
|
|
if (dev->l2ad_log_entries == 0)
|
|
return (B_FALSE);
|
|
|
|
int index = dev->l2ad_log_ent_idx++;
|
|
|
|
ASSERT3S(index, <, dev->l2ad_log_entries);
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
le = &lb->lb_entries[index];
|
|
bzero(le, sizeof (*le));
|
|
le->le_dva = hdr->b_dva;
|
|
le->le_birth = hdr->b_birth;
|
|
le->le_daddr = hdr->b_l2hdr.b_daddr;
|
|
if (index == 0)
|
|
dev->l2ad_log_blk_payload_start = le->le_daddr;
|
|
L2BLK_SET_LSIZE((le)->le_prop, HDR_GET_LSIZE(hdr));
|
|
L2BLK_SET_PSIZE((le)->le_prop, HDR_GET_PSIZE(hdr));
|
|
L2BLK_SET_COMPRESS((le)->le_prop, HDR_GET_COMPRESS(hdr));
|
|
le->le_complevel = hdr->b_complevel;
|
|
L2BLK_SET_TYPE((le)->le_prop, hdr->b_type);
|
|
L2BLK_SET_PROTECTED((le)->le_prop, !!(HDR_PROTECTED(hdr)));
|
|
L2BLK_SET_PREFETCH((le)->le_prop, !!(HDR_PREFETCH(hdr)));
|
|
|
|
dev->l2ad_log_blk_payload_asize += vdev_psize_to_asize(dev->l2ad_vdev,
|
|
HDR_GET_PSIZE(hdr));
|
|
|
|
return (dev->l2ad_log_ent_idx == dev->l2ad_log_entries);
|
|
}
|
|
|
|
/*
|
|
* Checks whether a given L2ARC device address sits in a time-sequential
|
|
* range. The trick here is that the L2ARC is a rotary buffer, so we can't
|
|
* just do a range comparison, we need to handle the situation in which the
|
|
* range wraps around the end of the L2ARC device. Arguments:
|
|
* bottom -- Lower end of the range to check (written to earlier).
|
|
* top -- Upper end of the range to check (written to later).
|
|
* check -- The address for which we want to determine if it sits in
|
|
* between the top and bottom.
|
|
*
|
|
* The 3-way conditional below represents the following cases:
|
|
*
|
|
* bottom < top : Sequentially ordered case:
|
|
* <check>--------+-------------------+
|
|
* | (overlap here?) |
|
|
* L2ARC dev V V
|
|
* |---------------<bottom>============<top>--------------|
|
|
*
|
|
* bottom > top: Looped-around case:
|
|
* <check>--------+------------------+
|
|
* | (overlap here?) |
|
|
* L2ARC dev V V
|
|
* |===============<top>---------------<bottom>===========|
|
|
* ^ ^
|
|
* | (or here?) |
|
|
* +---------------+---------<check>
|
|
*
|
|
* top == bottom : Just a single address comparison.
|
|
*/
|
|
boolean_t
|
|
l2arc_range_check_overlap(uint64_t bottom, uint64_t top, uint64_t check)
|
|
{
|
|
if (bottom < top)
|
|
return (bottom <= check && check <= top);
|
|
else if (bottom > top)
|
|
return (check <= top || bottom <= check);
|
|
else
|
|
return (check == top);
|
|
}
|
|
|
|
EXPORT_SYMBOL(arc_buf_size);
|
|
EXPORT_SYMBOL(arc_write);
|
|
EXPORT_SYMBOL(arc_read);
|
|
EXPORT_SYMBOL(arc_buf_info);
|
|
EXPORT_SYMBOL(arc_getbuf_func);
|
|
EXPORT_SYMBOL(arc_add_prune_callback);
|
|
EXPORT_SYMBOL(arc_remove_prune_callback);
|
|
|
|
/* BEGIN CSTYLED */
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "Min arc size");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, max, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "Max arc size");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_limit, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "Metadata limit for arc size");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_limit_percent,
|
|
param_set_arc_long, param_get_long, ZMOD_RW,
|
|
"Percent of arc size for arc meta limit");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_min, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "Min arc metadata");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_prune, INT, ZMOD_RW,
|
|
"Meta objects to scan for prune");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_adjust_restarts, INT, ZMOD_RW,
|
|
"Limit number of restarts in arc_evict_meta");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_strategy, INT, ZMOD_RW,
|
|
"Meta reclaim strategy");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, grow_retry, param_set_arc_int,
|
|
param_get_int, ZMOD_RW, "Seconds before growing arc size");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, p_dampener_disable, INT, ZMOD_RW,
|
|
"Disable arc_p adapt dampener");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, shrink_shift, param_set_arc_int,
|
|
param_get_int, ZMOD_RW, "log2(fraction of arc to reclaim)");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, pc_percent, UINT, ZMOD_RW,
|
|
"Percent of pagecache to reclaim arc to");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, p_min_shift, param_set_arc_int,
|
|
param_get_int, ZMOD_RW, "arc_c shift to calc min/max arc_p");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, average_blocksize, INT, ZMOD_RD,
|
|
"Target average block size");
|
|
|
|
ZFS_MODULE_PARAM(zfs, zfs_, compressed_arc_enabled, INT, ZMOD_RW,
|
|
"Disable compressed arc buffers");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min_prefetch_ms, param_set_arc_int,
|
|
param_get_int, ZMOD_RW, "Min life of prefetch block in ms");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min_prescient_prefetch_ms,
|
|
param_set_arc_int, param_get_int, ZMOD_RW,
|
|
"Min life of prescient prefetched block in ms");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, write_max, ULONG, ZMOD_RW,
|
|
"Max write bytes per interval");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, write_boost, ULONG, ZMOD_RW,
|
|
"Extra write bytes during device warmup");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, headroom, ULONG, ZMOD_RW,
|
|
"Number of max device writes to precache");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, headroom_boost, ULONG, ZMOD_RW,
|
|
"Compressed l2arc_headroom multiplier");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, trim_ahead, ULONG, ZMOD_RW,
|
|
"TRIM ahead L2ARC write size multiplier");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_secs, ULONG, ZMOD_RW,
|
|
"Seconds between L2ARC writing");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_min_ms, ULONG, ZMOD_RW,
|
|
"Min feed interval in milliseconds");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, noprefetch, INT, ZMOD_RW,
|
|
"Skip caching prefetched buffers");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_again, INT, ZMOD_RW,
|
|
"Turbo L2ARC warmup");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, norw, INT, ZMOD_RW,
|
|
"No reads during writes");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, meta_percent, INT, ZMOD_RW,
|
|
"Percent of ARC size allowed for L2ARC-only headers");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, rebuild_enabled, INT, ZMOD_RW,
|
|
"Rebuild the L2ARC when importing a pool");
|
|
|
|
ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, rebuild_blocks_min_l2size, ULONG, ZMOD_RW,
|
|
"Min size in bytes to write rebuild log blocks in L2ARC");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, lotsfree_percent, param_set_arc_int,
|
|
param_get_int, ZMOD_RW, "System free memory I/O throttle in bytes");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, sys_free, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "System free memory target size in bytes");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, dnode_limit, param_set_arc_long,
|
|
param_get_long, ZMOD_RW, "Minimum bytes of dnodes in arc");
|
|
|
|
ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, dnode_limit_percent,
|
|
param_set_arc_long, param_get_long, ZMOD_RW,
|
|
"Percent of ARC meta buffers for dnodes");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, dnode_reduce_percent, ULONG, ZMOD_RW,
|
|
"Percentage of excess dnodes to try to unpin");
|
|
|
|
ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, eviction_pct, INT, ZMOD_RW,
|
|
"When full, ARC allocation waits for eviction of this % of alloc size");
|
|
/* END CSTYLED */
|