linux/drivers/md
Guoqing Jiang e9eeba28a1 md/raid10: read balance chooses idlest disk for SSD
Andy reported that raid10 array with SSD disks has poor
read performance. Compared with raid1, RAID-1 can be 3x
faster than RAID-10 sometimes [1].

The thing is that raid10 chooses the low distance disk
for read request, however, the approach doesn't work
well for SSD device since it doesn't have spindle like
HDD, we should just read from the SSD which has less
pending IO like commit 9dedf60313 ("md/raid1: read
balance chooses idlest disk for SSD").

So this commit selects the idlest SSD disk for read if
array has none rotational disk, otherwise, read_balance
uses the previous distance priority algorithm. With the
change, the performance of raid10 gets increased largely
per Andy's test [2].

[1]. https://marc.info/?l=linux-raid&m=155915890004761&w=2
[2]. https://marc.info/?l=linux-raid&m=155990654223786&w=2

Tested-by: Andy Smith <andy@strugglers.net>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15 01:37:35 -06:00
..
bcache bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached 2019-06-13 03:09:15 -06:00
persistent-data treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
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 dm bufio: Simplify stack trace retrieval 2019-04-29 12:37:52 +02:00
dm-builtin.c
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 - Improve DM snapshot target's scalability by using finer grained 2019-05-16 15:55:48 -07:00
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: Make dm_dust_init and dm_dust_exit static 2019-05-07 16:05:07 -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 dm flakey: Properly corrupt multi-page bios. 2018-12-18 09:02:27 -05:00
dm-init.c dm init: fix max devices/targets checks 2019-04-30 16:51:23 -04:00
dm-integrity.c - Improve DM snapshot target's scalability by using finer grained 2019-05-16 15:55:48 -07:00
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 ioctl: fix hang in early create error condition 2019-05-16 09:52:06 -04:00
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: 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: eliminate 'split_discard_bios' flag from DM target interface 2019-02-20 23:24:55 -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 dm mpath: fix missing call of path selector type->end_io 2019-04-25 15:38:52 -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: Use fine-grained locking scheme 2019-04-18 16:18:30 -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
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 dax: Arrange for dax_supported check to span multiple devices 2019-05-20 15:02:08 -07:00
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: do not write metadata if no changes occurred 2019-04-18 16:18:34 -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 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
dm-verity.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
dm-writecache.c dm writecache: avoid unnecessary lookups in writecache_find_entry() 2019-04-26 11:48:03 -04:00
dm-zero.c
dm-zoned-metadata.c dm zoned: Fix zone report handling 2019-04-18 16:17:58 -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 zoned: Silence a static checker warning 2019-04-18 16:16:01 -04:00
dm-zoned.h
dm.c libnvdimm fixes v5.2-rc2 2019-05-25 10:11:23 -07:00
dm.h dax: Arrange for dax_supported check to span multiple devices 2019-05-20 15:02:08 -07:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile dm: add dust target 2019-04-30 16:37:19 -04:00
md-bitmap.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
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
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 md: fix spelling typo and add necessary space 2019-06-15 01:37:34 -06:00
md.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
raid0.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47 2019-05-24 17:27:13 +02:00
raid0.h
raid1-10.c md: raid1-10: Unify r{1,10}bio_pool_free 2019-06-15 01:37:35 -06:00
raid1.c md: raid1-10: Unify r{1,10}bio_pool_free 2019-06-15 01:37:35 -06:00
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 raid5-cache: Need to do start() part job after adding journal device 2019-06-15 01:37:34 -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