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OpenZFS 9442 - decrease indirect block size of spacemaps 

Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Albert Lee <trisk@forkgnu.org>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: George Melikov <mail@gmelikov.ru>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

Updates to indirect blocks of spacemaps can contribute significantly to
write inflation.  Therefore we want to reduce the indirect block size of
spacemaps from 128K to 16K.

Porting notes:
* Refactored to allow the dmu_object_alloc(), dmu_object_alloc_ibs()
  and dmu_object_alloc_dnsize() functions to use a common shared
  dmu_object_alloc_impl() function.

OpenZFS-issue: https://www.illumos.org/issues/9442
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0c2e6408b
Closes #7712
This commit is contained in:
Matthew Ahrens 2018-01-11 08:54:38 -08:00 committed by Brian Behlendorf
parent e106a7bacb
commit 3a549dc7a1
3 changed files with 50 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/sys/dmu.h
View File

@ -389,6 +389,9 @@ typedef struct dmu_buf {
*/
uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
uint64_t dmu_object_alloc_ibs(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
uint64_t dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonus_type, int bonus_len,
int dnodesize, dmu_tx_t *tx);

46
module/zfs/dmu_object.c
View File

@ -41,17 +41,10 @@
*/
int dmu_object_alloc_chunk_shift = 7;
uint64_t
dmu_object_alloc(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return dmu_object_alloc_dnsize(os, ot, blocksize, bonustype, bonuslen,
0, tx);
}
uint64_t
dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx)
static uint64_t
dmu_object_alloc_impl(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
int dnodesize, dmu_tx_t *tx)
{
uint64_t object;
uint64_t L1_dnode_count = DNODES_PER_BLOCK <<
@ -182,8 +175,9 @@ dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot, int blocksize,
* again now that we have the struct lock.
*/
if (dn->dn_type == DMU_OT_NONE) {
dnode_allocate(dn, ot, blocksize, 0,
bonustype, bonuslen, dn_slots, tx);
dnode_allocate(dn, ot, blocksize,
indirect_blockshift, bonustype,
bonuslen, dn_slots, tx);
rw_exit(&dn->dn_struct_rwlock);
dmu_tx_add_new_object(tx, dn);
dnode_rele(dn, FTAG);
@ -206,6 +200,31 @@ dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot, int blocksize,
}
}
uint64_t
dmu_object_alloc(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return dmu_object_alloc_impl(os, ot, blocksize, 0, bonustype,
bonuslen, 0, tx);
}
uint64_t
dmu_object_alloc_ibs(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
dmu_tx_t *tx)
{
return dmu_object_alloc_impl(os, ot, blocksize, indirect_blockshift,
bonustype, bonuslen, 0, tx);
}
uint64_t
dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx)
{
return (dmu_object_alloc_impl(os, ot, blocksize, 0, bonustype,
bonuslen, dnodesize, tx));
}
int
dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
@ -423,6 +442,7 @@ dmu_object_free_zapified(objset_t *mos, uint64_t object, dmu_tx_t *tx)
#if defined(_KERNEL)
EXPORT_SYMBOL(dmu_object_alloc);
EXPORT_SYMBOL(dmu_object_alloc_ibs);
EXPORT_SYMBOL(dmu_object_alloc_dnsize);
EXPORT_SYMBOL(dmu_object_claim);
EXPORT_SYMBOL(dmu_object_claim_dnsize);

19
module/zfs/space_map.c
View File

@ -52,6 +52,14 @@
*/
boolean_t zfs_force_some_double_word_sm_entries = B_FALSE;
/*
* Override the default indirect block size of 128K, instead use 16K for
* spacemaps (2^14 bytes). This dramatically reduces write inflation since
* appending to a spacemap typically has to write one data block (4KB) and one
* or two indirect blocks (16K-32K, rather than 128K).
*/
int space_map_ibs = 14;
boolean_t
sm_entry_is_debug(uint64_t e)
{
@ -674,8 +682,8 @@ space_map_write_impl(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
*
* [1] The feature is enabled.
* [2] The offset or run is too big for a single-word entry,
* or the vdev_id is set (meaning not equal to
* SM_NO_VDEVID).
* or the vdev_id is set (meaning not equal to
* SM_NO_VDEVID).
*
* Note that for purposes of testing we've added the case that
* we write two-word entries occasionally when the feature is
@ -837,7 +845,8 @@ space_map_truncate(space_map_t *sm, int blocksize, dmu_tx_t *tx)
*/
if ((spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) &&
doi.doi_bonus_size != sizeof (space_map_phys_t)) ||
doi.doi_data_block_size != blocksize) {
doi.doi_data_block_size != blocksize ||
doi.doi_metadata_block_size != 1 << space_map_ibs) {
zfs_dbgmsg("txg %llu, spa %s, sm %p, reallocating "
"object[%llu]: old bonus %u, old blocksz %u",
dmu_tx_get_txg(tx), spa_name(spa), sm, sm->sm_object,
@ -893,8 +902,8 @@ space_map_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
bonuslen = SPACE_MAP_SIZE_V0;
}
object = dmu_object_alloc(os, DMU_OT_SPACE_MAP, blocksize,
DMU_OT_SPACE_MAP_HEADER, bonuslen, tx);
object = dmu_object_alloc_ibs(os, DMU_OT_SPACE_MAP, blocksize,
space_map_ibs, DMU_OT_SPACE_MAP_HEADER, bonuslen, tx);
return (object);
}