linux/drivers/md
Huaisheng Ye 5229b4896e dm writecache: optimize performance by sorting the blocks for writeback_all
During the process of writeback, the blocks, which have been placed in wbl.list
for writeback soon, are partially ordered for the contiguous ones.

When writeback_all has been set, for most cases, also by default, there will be
a lot of blocks in pmem need to writeback at the same time.
For this case, we could optimize the performance by sorting all blocks in
wbl.list. writecache_writeback doesn't need to get blocks from the tail of
wc->lru, whereas from the first rb_node from the rb_tree.

The benefit is that, writecache_writeback doesn't need to have any cost to sort
the blocks, because of all blocks are incremental originally in rb_tree.
There will be a writecache_flush when writeback_all begins to work, that will
eliminate duplicate blocks in cache by committed/uncommitted.

Testing platform: Thinksystem SR630 with persistent memory.
The cache comes from pmem, which has 1006MB size. The origin device is HDD, 2GB
of which for using.

Testing steps:
 1) dmsetup create mycache --table '0 4194304 writecache p /dev/sdb1 /dev/pmem4  4096 0'
 2) fio -filename=/dev/mapper/mycache -direct=1 -iodepth=20 -rw=randwrite
 -ioengine=libaio -bs=4k -loops=1  -size=2g -group_reporting -name=mytest1
 3) time dmsetup message /dev/mapper/mycache 0 flush

Here is the results below,
With the patch:
 # fio -filename=/dev/mapper/mycache -direct=1 -iodepth=20 -rw=randwrite
 -ioengine=libaio -bs=4k -loops=1  -size=2g -group_reporting -name=mytest1
   iops        : min= 1582, max=199470, avg=5305.94, stdev=21273.44, samples=197
 # time dmsetup message /dev/mapper/mycache 0 flush
real	0m44.020s
user	0m0.002s
sys	0m0.003s

Without the patch:
 # fio -filename=/dev/mapper/mycache -direct=1 -iodepth=20 -rw=randwrite
 -ioengine=libaio -bs=4k -loops=1  -size=2g -group_reporting -name=mytest1
   iops        : min= 1202, max=197650, avg=4968.67, stdev=20480.17, samples=211
 # time dmsetup message /dev/mapper/mycache 0 flush
real	1m39.221s
user	0m0.001s
sys	0m0.003s

I also have checked the data accuracy with this patch by making EXT4 filesystem
on mycache, then mount it for checking md5 of files on that.
The test result is positive, with this patch it could save more than half of time
when writeback_all.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-08-26 10:59:00 -04:00
..
bcache bcache: Revert "bcache: use sysfs_match_string() instead of __sysfs_match_string()" 2019-08-09 07:37:33 -06:00
persistent-data dm space map metadata: fix missing store of apply_bops() return value 2019-08-22 16:11:24 -04:00
dm-bio-prison-v1.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v1.h block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
dm-bio-prison-v2.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v2.h
dm-bio-record.h block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-bufio.c Revert "dm bufio: fix deadlock with loop device" 2019-08-15 15:57:39 -04:00
dm-builtin.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-cache-background-tracker.c dm cache background tracker: fix sparse warning 2018-04-30 15:40:40 -04:00
dm-cache-background-tracker.h
dm-cache-block-types.h
dm-cache-metadata.c dm cache metadata: Fix loading discard bitset 2019-04-18 16:18:25 -04:00
dm-cache-metadata.h
dm-cache-policy-internal.h
dm-cache-policy-smq.c dm: remove unnecessary unlikely() around WARN_ON_ONCE() 2018-10-16 14:34:59 -04:00
dm-cache-policy.c
dm-cache-policy.h
dm-cache-target.c dm cache: add support for discard passdown to the origin device 2019-03-05 14:53:52 -05:00
dm-core.h dm: disable DISCARD if the underlying storage no longer supports it 2019-04-04 15:33:59 -04:00
dm-crypt.c dm crypt: reuse eboiv skcipher for IV generation 2019-08-23 10:13:13 -04:00
dm-delay.c dm delay: fix a crash when invalid device is specified 2019-04-26 11:29:32 -04:00
dm-dust.c dm dust: use dust block size for badblocklist index 2019-08-21 11:27:17 -04:00
dm-era-target.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
dm-exception-store.c
dm-exception-store.h - Improve DM snapshot target's scalability by using finer grained 2019-05-16 15:55:48 -07:00
dm-flakey.c block: Kill gfp_t argument of blkdev_report_zones() 2019-07-11 20:04:37 -06:00
dm-init.c docs: device-mapper: move it to the admin-guide 2019-07-15 11:03:01 -03:00
dm-integrity.c dm integrity: fix a crash due to BUG_ON in __journal_read_write() 2019-08-15 16:01:57 -04:00
dm-io.c dm: Use kzalloc for all structs with embedded biosets/mempools 2018-06-05 08:47:43 -06:00
dm-ioctl.c dm: make dm_table_find_target return NULL 2019-08-23 10:13:12 -04:00
dm-kcopyd.c dm kcopyd: always complete failed jobs 2019-08-15 15:57:39 -04:00
dm-linear.c block: Kill gfp_t argument of blkdev_report_zones() 2019-07-11 20:04:37 -06:00
dm-log-userspace-base.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log-writes.c dm log writes: fix incorrect comment about the logged sequence example 2019-07-09 14:13:33 -04:00
dm-log.c
dm-mpath.c dm mpath: always free attached_handler_name in parse_path() 2019-04-30 16:51:30 -04:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-raid1.c dm: Check for device sector overflow if CONFIG_LBDAF is not set 2018-12-18 09:02:26 -05:00
dm-raid.c dm raid: add missing cleanup in raid_ctr() 2019-08-21 11:47:05 -04:00
dm-region-hash.c - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
dm-round-robin.c
dm-rq.c dm: update stale comment in end_clone_bio() 2019-07-09 14:14:20 -04:00
dm-rq.h dm: remove unused _rq_tio_cache and _rq_cache 2019-03-05 14:48:50 -05:00
dm-service-time.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-snap-persistent.c dm bufio: move dm-bufio.h to include/linux/ 2018-04-03 15:04:23 -04:00
dm-snap-transient.c
dm-snap.c dm snapshot: fix oversights in optional discard support 2019-07-17 11:12:30 -04:00
dm-stats.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
dm-stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-stripe.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-switch.c dm switch: use struct_size() in kzalloc() 2019-03-05 14:48:51 -05:00
dm-sysfs.c dm: remove legacy request-based IO path 2018-10-11 11:36:09 -04:00
dm-table.c dm: make dm_table_find_target return NULL 2019-08-23 10:13:12 -04:00
dm-target.c dm mpath: fix missing call of path selector type->end_io 2019-04-25 15:38:52 -04:00
dm-thin-metadata.c dm thin metadata: check if in fail_io mode when setting needs_check 2019-07-02 15:50:08 -04:00
dm-thin-metadata.h dm thin: fix passdown_double_checking_shared_status() 2019-01-15 16:10:41 -05:00
dm-thin.c dm thin: add sanity checks to thin-pool and external snapshot creation 2019-03-05 14:53:49 -05:00
dm-uevent.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
dm-uevent.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
dm-unstripe.c dm: Check for device sector overflow if CONFIG_LBDAF is not set 2018-12-18 09:02:26 -05:00
dm-verity-fec.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dm-verity-fec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dm-verity-target.c dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
dm-verity-verify-sig.c dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
dm-verity-verify-sig.h dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
dm-verity.h dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
dm-writecache.c dm writecache: optimize performance by sorting the blocks for writeback_all 2019-08-26 10:59:00 -04:00
dm-zero.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-zoned-metadata.c dm zoned: fix potential NULL dereference in dmz_do_reclaim() 2019-08-21 11:29:30 -04:00
dm-zoned-reclaim.c dm zoned: fix a few typos 2019-08-15 15:57:43 -04:00
dm-zoned-target.c dm zoned: fix invalid memory access 2019-08-26 10:33:58 -04:00
dm-zoned.h dm zoned: add SPDX license identifiers 2019-08-15 15:57:42 -04:00
dm.c dm: make dm_table_find_target return NULL 2019-08-23 10:13:12 -04:00
dm.h dm: make dm_table_find_target return NULL 2019-08-23 10:13:12 -04:00
Kconfig dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
Makefile dm verity: add root hash pkcs#7 signature verification 2019-08-23 10:13:14 -04:00
md-bitmap.c md-bitmap: create and destroy wb_info_pool with the change of bitmap 2019-06-20 16:36:00 -07:00
md-bitmap.h md: Avoid namespace collision with bitmap API 2018-08-01 15:49:39 -07:00
md-cluster.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 45 2019-05-24 17:27:12 +02:00
md-cluster.h md-cluster: introduce resync_info_get interface for sanity check 2018-10-18 09:36:35 -07:00
md-faulty.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
md-linear.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
md-linear.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-11-14 16:07:26 -08:00
md-multipath.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
md-multipath.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md.c Merge branch 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2019-07-14 16:17:18 -07:00
md.h md: introduce mddev_create/destroy_wb_pool for the change of member device 2019-06-20 16:36:00 -07:00
raid0.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
raid0.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1-10.c md: raid1-10: Unify r{1,10}bio_pool_free 2019-06-15 01:37:35 -06:00
raid1.c md/raid1: Fix a warning message in remove_wb() 2019-06-26 12:18:48 -07:00
raid1.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5-cache.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
raid5-log.h raid5: set write hint for PPL 2019-03-12 10:15:18 -07:00
raid5-ppl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
raid5.c block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
raid5.h md: convert to kvmalloc 2019-03-12 10:04:02 -07:00
raid10.c md/raid10: read balance chooses idlest disk for SSD 2019-06-15 01:37:35 -06:00
raid10.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00