NeilBrown 2bc13b83e6 md: batch flush requests. ... Currently if many flush requests are submitted to an md device is quick succession, they are serialized and can take a long to process them all. We don't really need to call flush all those times - a single flush call can satisfy all requests submitted before it started. So keep track of when the current flush started and when it finished, allow any pending flush that was requested before the flush started to complete without waiting any more. Test results from Xiao: Test is done on a raid10 device which is created by 4 SSDs. The tool is dbench. 1. The latest linux stable kernel Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 768 10.509 78.305 Flush 2078376 0.013 10.094 Close 21787697 0.019 18.821 LockX 96580 0.007 3.184 Mkdir 384 0.008 0.062 Rename 1255883 0.191 23.534 ReadX 46495589 0.020 14.230 WriteX 14790591 7.123 60.706 Unlink 5989118 0.440 54.551 UnlockX 96580 0.005 2.736 FIND_FIRST 10393845 0.042 12.079 SET_FILE_INFORMATION 2415558 0.129 10.088 QUERY_FILE_INFORMATION 4711725 0.005 8.462 QUERY_PATH_INFORMATION 26883327 0.032 21.715 QUERY_FS_INFORMATION 4929409 0.010 8.238 NTCreateX 29660080 0.100 53.268 Throughput 1034.88 MB/sec (sync open) 128 clients 128 procs max_latency=60.712 ms 2. With patch1 "Revert "MD: fix lock contention for flush bios"" Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 256 8.326 36.761 Flush 693291 3.974 180.269 Close 7266404 0.009 36.929 LockX 32160 0.006 0.840 Mkdir 128 0.008 0.021 Rename 418755 0.063 29.945 ReadX 15498708 0.007 7.216 WriteX 4932310 22.482 267.928 Unlink 1997557 0.109 47.553 UnlockX 32160 0.004 1.110 FIND_FIRST 3465791 0.036 7.320 SET_FILE_INFORMATION 805825 0.015 1.561 QUERY_FILE_INFORMATION 1570950 0.005 2.403 QUERY_PATH_INFORMATION 8965483 0.013 14.277 QUERY_FS_INFORMATION 1643626 0.009 3.314 NTCreateX 9892174 0.061 41.278 Throughput 345.009 MB/sec (sync open) 128 clients 128 procs max_latency=267.939 m 3. With patch1 and patch2 Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 768 9.570 54.588 Flush 2061354 0.666 15.102 Close 21604811 0.012 25.697 LockX 95770 0.007 1.424 Mkdir 384 0.008 0.053 Rename 1245411 0.096 12.263 ReadX 46103198 0.011 12.116 WriteX 14667988 7.375 60.069 Unlink 5938936 0.173 30.905 UnlockX 95770 0.005 4.147 FIND_FIRST 10306407 0.041 11.715 SET_FILE_INFORMATION 2395987 0.048 7.640 QUERY_FILE_INFORMATION 4672371 0.005 9.291 QUERY_PATH_INFORMATION 26656735 0.018 19.719 QUERY_FS_INFORMATION 4887940 0.010 7.654 NTCreateX 29410811 0.059 28.551 Throughput 1026.21 MB/sec (sync open) 128 clients 128 procs max_latency=60.075 ms Cc: <stable@vger.kernel.org> # v4.19+ Tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2019-04-01 12:11:48 -06:00
..
bcache	block: allow bio_for_each_segment_all() to iterate over multi-page bvec	2019-02-15 08:40:11 -07:00
persistent-data	dm block manager: remove redundant unlikely annotation	2019-03-05 14:53:48 -05:00
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
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
dm-bufio.c	Merge branch 'akpm' (patches from Andrew)	2018-12-28 16:55:46 -08:00
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: verify cache has blocks in blocks_are_clean_separate_dirty()	2018-12-07 16:04:09 -05:00
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: don't reuse bio for flushes	2018-12-19 09:13:34 -07:00
dm-crypt.c	for-5.1/block-20190302	2019-03-08 14:12:17 -08:00
dm-delay.c	dm: Check for device sector overflow if CONFIG_LBDAF is not set	2018-12-18 09:02:26 -05:00
dm-era-target.c	dm: allow targets to return output from messages they are sent	2018-04-03 15:04:10 -04:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c	dm flakey: Properly corrupt multi-page bios.	2018-12-18 09:02:27 -05:00
dm-init.c	dm: add support to directly boot to a mapped device	2019-03-05 14:53:50 -05:00
dm-integrity.c	dm integrity: limit the rate of error messages	2019-03-06 09:03:00 -05:00
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: add support to directly boot to a mapped device	2019-03-05 14:53:50 -05:00
dm-kcopyd.c	dm kcopyd: Fix bug causing workqueue stalls	2018-12-18 09:02:26 -05:00
dm-linear.c	dm: Check for device sector overflow if CONFIG_LBDAF is not set	2018-12-18 09:02:26 -05:00
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	dax: Introduce a ->copy_to_iter dax operation	2018-05-22 23:18:31 -07:00
dm-log.c
dm-mpath.c	dm mpath: only flush workqueue when needed	2018-12-18 09:02:25 -05:00
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-raid.c	dm: eliminate 'split_discard_bios' flag from DM target interface	2019-02-20 23:24:55 -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-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	- Update bio-based DM core to always call blk_queue_split() and update	2019-03-09 17:40:27 -08:00
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: don't define direct_access if we don't support it	2019-03-05 14:53:52 -05:00
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	block: kill QUEUE_FLAG_NO_SG_MERGE	2019-02-15 08:40:12 -07:00
dm-target.c	dm: remove unused macro DM_MOD_NAME_SIZE	2018-04-03 15:04:15 -04:00
dm-thin-metadata.c	dm thin: fix passdown_double_checking_shared_status()	2019-01-15 16:10:41 -05:00
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
dm-uevent.h
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	dm verity fec: remove redundant unlikely annotation	2019-03-05 14:53:48 -05:00
dm-verity-fec.h	dm: convert to bioset_init()/mempool_init()	2018-05-30 15:33:32 -06:00
dm-verity-target.c	dm verity: log the hash algorithm implementation	2018-12-18 09:02:27 -05:00
dm-verity.h	dm verity: add 'check_at_most_once' option to only validate hashes once	2018-04-03 15:04:29 -04:00
dm-writecache.c	dm writecache: fix typo in name for writeback_wq	2019-03-05 14:53:51 -05:00
dm-zero.c
dm-zoned-metadata.c	dm zoned: fix various dmz_get_mblock() issues	2018-10-18 15:17:03 -04:00
dm-zoned-reclaim.c	dm kcopyd: return void from dm_kcopyd_copy()	2018-07-31 17:33:21 -04:00
dm-zoned-target.c	dm: eliminate 'split_discard_bios' flag from DM target interface	2019-02-20 23:24:55 -05:00
dm-zoned.h
dm.c	dm: always call blk_queue_split() in dm_process_bio()	2019-03-05 14:53:32 -05:00
dm.h	dm: remove legacy request-based IO path	2018-10-11 11:36:09 -04:00
Kconfig	dm: add support to directly boot to a mapped device	2019-03-05 14:53:50 -05:00
Makefile	dm: add support to directly boot to a mapped device	2019-03-05 14:53:50 -05:00
md-bitmap.c	md/bitmap: use mddev_suspend/resume instead of ->quiesce()	2018-10-10 11:03:34 -07:00
md-bitmap.h	md: Avoid namespace collision with bitmap API	2018-08-01 15:49:39 -07:00
md-cluster.c	md-cluster: remove suspend_info	2018-10-18 09:41:25 -07:00
md-cluster.h	md-cluster: introduce resync_info_get interface for sanity check	2018-10-18 09:36:35 -07:00
md-faulty.c	md: convert to bioset_init()/mempool_init()	2018-05-30 15:33:32 -06:00
md-linear.c	md-linear: use struct_size() in kzalloc()	2019-02-04 10:37:11 -08:00
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: kzalloc() -> kcalloc()	2018-06-12 16:19:22 -07:00
md-multipath.h	md: convert to bioset_init()/mempool_init()	2018-05-30 15:33:32 -06:00
md.c	md: batch flush requests.	2019-04-01 12:11:48 -06:00
md.h	md: batch flush requests.	2019-04-01 12:11:48 -06:00
raid0.c	blkcg: remove bio->bi_css and instead use bio->bi_blkg	2018-12-07 22:26:37 -07:00
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	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
raid1.c	for-5.1/block-20190302	2019-03-08 14:12:17 -08:00
raid1.h	md: convert to bioset_init()/mempool_init()	2018-05-30 15:33:32 -06:00
raid5-cache.c	md/raid5: fix 'out of memory' during raid cache recovery	2019-01-28 11:44:40 -08:00
raid5-log.h	raid5: set write hint for PPL	2019-03-12 10:15:18 -07:00
raid5-ppl.c	for-5.1/block-post-20190315	2019-03-16 12:36:39 -07:00
raid5.c	Don't jump to compute_result state from check_result state	2019-04-01 12:11:48 -06:00
raid5.h	md: convert to kvmalloc	2019-03-12 10:04:02 -07:00
raid10.c	md: Fix failed allocation of md_register_thread	2019-03-12 10:15:18 -07:00
raid10.h	md: convert to bioset_init()/mempool_init()	2018-05-30 15:33:32 -06:00