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Illumos 4873 - zvol unmap calls can take a very long time for larger datasets 

4873 zvol unmap calls can take a very long time for larger datasets
Author: Alex Reece <alex@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Basil Crow <basil.crow@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  https://www.illumos.org/issues/4873
  https://github.com/illumos/illumos-gate/commit/0f6d88a

Porting Notes:

dbuf_free_range():
  - reduce stack usage using kmem_alloc()
  - the sorted AVL tree will handle the spill block case correctly
    without all the special handling in the for() loop

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Alex Reece 2015-04-03 14:14:28 +11:00 committed by Brian Behlendorf
parent 58c4aa00c6
commit 8951cb8dfb
7 changed files with 138 additions and 49 deletions
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9
include/sys/avl.h
View File

@ -23,6 +23,10 @@
* Use is subject to license terms.
*/
/*
* Copyright (c) 2014 by Delphix. All rights reserved.
*/
#ifndef _AVL_H
#define _AVL_H
@ -259,6 +263,11 @@ extern boolean_t avl_update(avl_tree_t *, void *);
extern boolean_t avl_update_lt(avl_tree_t *, void *);
extern boolean_t avl_update_gt(avl_tree_t *, void *);
/*
* Swaps the contents of the two trees.
*/
extern void avl_swap(avl_tree_t *tree1, avl_tree_t *tree2);
/*
* Return the number of nodes in the tree
*/

7
include/sys/dbuf.h
View File

@ -20,7 +20,7 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013 by Delphix. All rights reserved.
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
*/
@ -213,11 +213,14 @@ typedef struct dmu_buf_impl {
/* pointer to most recent dirty record for this buffer */
dbuf_dirty_record_t *db_last_dirty;
/* Creation time of dbuf (see comment in dbuf_compare). */
hrtime_t db_creation;
/*
* Our link on the owner dnodes's dn_dbufs list.
* Protected by its dn_dbufs_mtx.
*/
list_node_t db_link;
avl_node_t db_link;
/* Data which is unique to data (leaf) blocks: */

2
include/sys/dnode.h
View File

@ -233,7 +233,7 @@ typedef struct dnode {
refcount_t dn_holds;
kmutex_t dn_dbufs_mtx;
list_t dn_dbufs; /* descendent dbufs */
avl_tree_t dn_dbufs; /* descendent dbufs */
/* protected by dn_struct_rwlock */
struct dmu_buf_impl *dn_bonus; /* bonus buffer dbuf */

30
module/avl/avl.c
View File

@ -23,6 +23,10 @@
* Use is subject to license terms.
*/
/*
* Copyright (c) 2014 by Delphix. All rights reserved.
*/
/*
* AVL - generic AVL tree implementation for kernel use
*
@ -85,6 +89,12 @@
* is a modified "avl_node_t *". The bottom bit (normally 0 for a
* pointer) is set to indicate if that the new node has a value greater
* than the value of the indicated "avl_node_t *".
*
* Note - in addition to userland (e.g. libavl and libutil) and the kernel
* (e.g. genunix), avl.c is compiled into ld.so and kmdb's genunix module,
* which each have their own compilation environments and subsequent
* requirements. Each of these environments must be considered when adding
* dependencies from avl.c.
*/
#include <sys/types.h>
@ -863,6 +873,24 @@ avl_update(avl_tree_t *t, void *obj)
return (B_FALSE);
}
void
avl_swap(avl_tree_t *tree1, avl_tree_t *tree2)
{
avl_node_t *temp_node;
ulong_t temp_numnodes;
ASSERT3P(tree1->avl_compar, ==, tree2->avl_compar);
ASSERT3U(tree1->avl_offset, ==, tree2->avl_offset);
ASSERT3U(tree1->avl_size, ==, tree2->avl_size);
temp_node = tree1->avl_root;
temp_numnodes = tree1->avl_numnodes;
tree1->avl_root = tree2->avl_root;
tree1->avl_numnodes = tree2->avl_numnodes;
tree2->avl_root = temp_node;
tree2->avl_numnodes = temp_numnodes;
}
/*
* initialize a new AVL tree
*/
@ -1058,6 +1086,8 @@ EXPORT_SYMBOL(avl_first);
EXPORT_SYMBOL(avl_last);
EXPORT_SYMBOL(avl_nearest);
EXPORT_SYMBOL(avl_add);
EXPORT_SYMBOL(avl_swap);
EXPORT_SYMBOL(avl_is_empty);
EXPORT_SYMBOL(avl_remove);
EXPORT_SYMBOL(avl_numnodes);
EXPORT_SYMBOL(avl_destroy_nodes);

68
module/zfs/dbuf.c
View File

@ -93,7 +93,9 @@ dbuf_cons(void *vdb, void *unused, int kmflag)
mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
refcount_create(&db->db_holds);
list_link_init(&db->db_link);
db->db_creation = gethrtime();
return (0);
}
@ -386,7 +388,7 @@ dbuf_verify(dmu_buf_impl_t *db)
ASSERT3U(db->db_level, <, dn->dn_nlevels);
ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
db->db_blkid == DMU_SPILL_BLKID ||
!list_is_empty(&dn->dn_dbufs));
!avl_is_empty(&dn->dn_dbufs));
}
if (db->db_blkid == DMU_BONUS_BLKID) {
ASSERT(dn != NULL);
@ -866,23 +868,34 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
* receive; see comment below for details.
*/
void
dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid,
dmu_tx_t *tx)
{
dmu_buf_impl_t *db, *db_next;
dmu_buf_impl_t *db, *db_next, *db_search;
uint64_t txg = tx->tx_txg;
avl_index_t where;
boolean_t freespill =
(start == DMU_SPILL_BLKID || end == DMU_SPILL_BLKID);
(start_blkid == DMU_SPILL_BLKID || end_blkid == DMU_SPILL_BLKID);
if (end > dn->dn_maxblkid && !freespill)
end = dn->dn_maxblkid;
dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
if (end_blkid > dn->dn_maxblkid && !freespill)
end_blkid = dn->dn_maxblkid;
dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid);
db_seach = kmem_alloc(sizeof (dmu_buf_impl_t), KM_SLEEP);
db_search->db_level = 0;
db_search->db_blkid = start_blkid;
db_search->db_creation = 0;
mutex_enter(&dn->dn_dbufs_mtx);
if (start >= dn->dn_unlisted_l0_blkid * dn->dn_datablksz &&
!freespill) {
if (start_blkid >= dn->dn_unlisted_l0_blkid && !freespill) {
/* There can't be any dbufs in this range; no need to search. */
mutex_exit(&dn->dn_dbufs_mtx);
return;
#ifdef DEBUG
db = avl_find(&dn->dn_dbufs, db_search, &where);
ASSERT3P(db, ==, NULL);
db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
ASSERT(db == NULL || db->db_level > 0);
#endif
goto out;
} else if (dmu_objset_is_receiving(dn->dn_objset)) {
/*
* If we are receiving, we expect there to be no dbufs in
@ -894,19 +907,18 @@ dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
atomic_inc_64(&zfs_free_range_recv_miss);
}
for (db = list_head(&dn->dn_dbufs); db != NULL; db = db_next) {
db_next = list_next(&dn->dn_dbufs, db);
db = avl_find(&dn->dn_dbufs, db_search, &where);
ASSERT3P(db, ==, NULL);
db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
for (; db != NULL; db = db_next) {
db_next = AVL_NEXT(&dn->dn_dbufs, db);
ASSERT(db->db_blkid != DMU_BONUS_BLKID);
/* Skip indirect blocks. */
if (db->db_level != 0)
continue;
/* Skip direct blocks outside the range. */
if (!freespill && (db->db_blkid < start || db->db_blkid > end))
continue;
/* Skip all direct blocks, only free spill blocks. */
if (freespill && (db->db_blkid != DMU_SPILL_BLKID))
continue;
if (db->db_level != 0 || db->db_blkid > end_blkid) {
break;
}
ASSERT3U(db->db_blkid, >=, start_blkid);
/* found a level 0 buffer in the range */
mutex_enter(&db->db_mtx);
@ -968,6 +980,9 @@ dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
mutex_exit(&db->db_mtx);
}
out:
kmem_free(db_search, sizeof (dmu_buf_impl_t));
mutex_exit(&dn->dn_dbufs_mtx);
}
@ -1657,7 +1672,7 @@ dbuf_clear(dmu_buf_impl_t *db)
dn = DB_DNODE(db);
dndb = dn->dn_dbuf;
if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
list_remove(&dn->dn_dbufs, db);
avl_remove(&dn->dn_dbufs, db);
atomic_dec_32(&dn->dn_dbufs_count);
membar_producer();
DB_DNODE_EXIT(db);
@ -1829,7 +1844,7 @@ dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
mutex_exit(&dn->dn_dbufs_mtx);
return (odb);
}
list_insert_head(&dn->dn_dbufs, db);
avl_add(&dn->dn_dbufs, db);
if (db->db_level == 0 && db->db_blkid >=
dn->dn_unlisted_l0_blkid)
dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
@ -1888,7 +1903,7 @@ dbuf_destroy(dmu_buf_impl_t *db)
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
mutex_enter(&dn->dn_dbufs_mtx);
list_remove(&dn->dn_dbufs, db);
avl_remove(&dn->dn_dbufs, db);
atomic_dec_32(&dn->dn_dbufs_count);
mutex_exit(&dn->dn_dbufs_mtx);
DB_DNODE_EXIT(db);
@ -1906,7 +1921,6 @@ dbuf_destroy(dmu_buf_impl_t *db)
db->db_parent = NULL;
db->db_buf = NULL;
ASSERT(!list_link_active(&db->db_link));
ASSERT(db->db.db_data == NULL);
ASSERT(db->db_hash_next == NULL);
ASSERT(db->db_blkptr == NULL);

59
module/zfs/dnode.c
View File

@ -62,6 +62,43 @@ int zfs_default_ibs = DN_MAX_INDBLKSHIFT;
static kmem_cbrc_t dnode_move(void *, void *, size_t, void *);
#endif /* _KERNEL */
static int
dbuf_compare(const void *x1, const void *x2)
{
const dmu_buf_impl_t *d1 = x1;
const dmu_buf_impl_t *d2 = x2;
if (d1->db_level < d2->db_level) {
return (-1);
} else if (d1->db_level > d2->db_level) {
return (1);
}
if (d1->db_blkid < d2->db_blkid) {
return (-1);
} else if (d1->db_blkid > d2->db_blkid) {
return (1);
}
/*
* If a dbuf is being evicted while dn_dbufs_mutex is not held, we set
* the db_state to DB_EVICTING but do not remove it from dn_dbufs. If
* another thread creates a dbuf of the same blkid before the dbuf is
* removed from dn_dbufs, we can reach a state where there are two
* dbufs of the same blkid and level in db_dbufs. To maintain the avl
* invariant that there cannot be duplicate items, we distinguish
* between these two dbufs based on the time they were created.
*/
if (d1->db_creation < d2->db_creation) {
return (-1);
} else if (d1->db_creation > d2->db_creation) {
return (1);
} else {
ASSERT3P(d1, ==, d2);
return (0);
}
}
/* ARGSUSED */
static int
dnode_cons(void *arg, void *unused, int kmflag)
@ -116,7 +153,7 @@ dnode_cons(void *arg, void *unused, int kmflag)
dn->dn_dbufs_count = 0;
dn->dn_unlisted_l0_blkid = 0;
list_create(&dn->dn_dbufs, sizeof (dmu_buf_impl_t),
avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
dn->dn_moved = 0;
@ -169,7 +206,7 @@ dnode_dest(void *arg, void *unused)
ASSERT0(dn->dn_dbufs_count);
ASSERT0(dn->dn_unlisted_l0_blkid);
list_destroy(&dn->dn_dbufs);
avl_destroy(&dn->dn_dbufs);
}
void
@ -503,7 +540,7 @@ dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
ASSERT0(dn->dn_assigned_txg);
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
ASSERT3U(refcount_count(&dn->dn_holds), <=, 1);
ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
ASSERT(avl_is_empty(&dn->dn_dbufs));
for (i = 0; i < TXG_SIZE; i++) {
ASSERT0(dn->dn_next_nblkptr[i]);
@ -689,8 +726,8 @@ dnode_move_impl(dnode_t *odn, dnode_t *ndn)
ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset;
ASSERT(refcount_count(&odn->dn_tx_holds) == 0);
refcount_transfer(&ndn->dn_holds, &odn->dn_holds);
ASSERT(list_is_empty(&ndn->dn_dbufs));
list_move_tail(&ndn->dn_dbufs, &odn->dn_dbufs);
ASSERT(avl_is_empty(&ndn->dn_dbufs));
avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs);
ndn->dn_dbufs_count = odn->dn_dbufs_count;
ndn->dn_unlisted_l0_blkid = odn->dn_unlisted_l0_blkid;
ndn->dn_bonus = odn->dn_bonus;
@ -724,7 +761,7 @@ dnode_move_impl(dnode_t *odn, dnode_t *ndn)
*/
odn->dn_dbuf = NULL;
odn->dn_handle = NULL;
list_create(&odn->dn_dbufs, sizeof (dmu_buf_impl_t),
avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
odn->dn_dbufs_count = 0;
odn->dn_unlisted_l0_blkid = 0;
@ -1238,7 +1275,8 @@ dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
return;
}
ASSERT(!refcount_is_zero(&dn->dn_holds) || list_head(&dn->dn_dbufs));
ASSERT(!refcount_is_zero(&dn->dn_holds) ||
!avl_is_empty(&dn->dn_dbufs));
ASSERT(dn->dn_datablksz != 0);
ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]);
ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]);
@ -1311,7 +1349,7 @@ dnode_free(dnode_t *dn, dmu_tx_t *tx)
int
dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
{
dmu_buf_impl_t *db, *db_next;
dmu_buf_impl_t *db;
int err;
if (size == 0)
@ -1334,9 +1372,8 @@ dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
goto fail;
mutex_enter(&dn->dn_dbufs_mtx);
for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
db_next = list_next(&dn->dn_dbufs, db);
for (db = avl_first(&dn->dn_dbufs); db != NULL;
db = AVL_NEXT(&dn->dn_dbufs, db)) {
if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID &&
db->db_blkid != DMU_SPILL_BLKID) {
mutex_exit(&dn->dn_dbufs_mtx);

12
module/zfs/dnode_sync.c
View File

@ -406,16 +406,13 @@ dnode_evict_dbufs(dnode_t *dn)
int pass = 0;
do {
dmu_buf_impl_t *db, marker;
dmu_buf_impl_t *db, *db_next;
int evicting = FALSE;
progress = FALSE;
mutex_enter(&dn->dn_dbufs_mtx);
list_insert_tail(&dn->dn_dbufs, &marker);
db = list_head(&dn->dn_dbufs);
for (; db != &marker; db = list_head(&dn->dn_dbufs)) {
list_remove(&dn->dn_dbufs, db);
list_insert_tail(&dn->dn_dbufs, db);
for (db = avl_first(&dn->dn_dbufs); db != NULL; db = db_next) {
db_next = AVL_NEXT(&dn->dn_dbufs, db);
#ifdef DEBUG
DB_DNODE_ENTER(db);
ASSERT3P(DB_DNODE(db), ==, dn);
@ -435,7 +432,6 @@ dnode_evict_dbufs(dnode_t *dn)
}
}
list_remove(&dn->dn_dbufs, &marker);
/*
* NB: we need to drop dn_dbufs_mtx between passes so
* that any DB_EVICTING dbufs can make progress.
@ -516,7 +512,7 @@ dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
dnode_evict_dbufs(dn);
ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
ASSERT(avl_is_empty(&dn->dn_dbufs));
ASSERT3P(dn->dn_bonus, ==, NULL);
/*