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Shaohua Li f984df1f0f blk-mq: do limited block plug for multiple queue case
plug is still helpful for workload with IO merge, but it can be harmful
otherwise especially with multiple hardware queues, as there is
(supposed) no lock contention in this case and plug can introduce
latency. For multiple queues, we do limited plug, eg plug only if there
is request merge. If a request doesn't have merge with following
request, the requet will be dispatched immediately.

V2: check blk_queue_nomerges() as suggested by Jeff.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08 14:17:21 -06:00
..
partitions Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block 2015-02-12 14:13:23 -08:00
Kconfig block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
Kconfig.iosched blkcg: make CONFIG_BLK_CGROUP bool 2012-03-06 21:27:21 +01:00
Makefile block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
bio-integrity.c block: fix regression where bio_integrity_process uses wrong bio_vec iterator 2014-12-02 08:15:21 -07:00
bio.c bio: skip atomic inc/dec of ->bi_cnt for most use cases 2015-05-05 13:32:49 -06:00
blk-cgroup.c blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-cgroup.h blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-core.c blk: clean up plug 2015-05-08 14:17:14 -06:00
blk-exec.c block: move PM request support to IDE 2015-05-05 13:40:42 -06:00
blk-flush.c blk-mq: support per-distpatch_queue flush machinery 2014-09-25 15:22:45 -06:00
blk-integrity.c block: Don't merge requests if integrity flags differ 2014-09-27 09:14:57 -06:00
blk-ioc.c block: Substitute rcu_access_pointer() for rcu_dereference_raw() 2014-02-18 12:21:26 -08:00
blk-iopoll.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-03 12:57:53 -07:00
blk-lib.c block: Quiesce zeroout wrapper 2015-02-05 10:14:54 -07:00
blk-map.c blk_rq_map_user(): use import_single_range() 2015-04-11 22:27:13 -04:00
blk-merge.c Fix bug in blk_rq_merge_ok 2015-03-20 08:50:41 -06:00
blk-mq-cpu.c blk-mq: add file comments and update copyright notices 2014-05-28 10:15:41 -06:00
blk-mq-cpumap.c blk-mq: Use all available hardware queues 2014-12-09 09:08:21 -07:00
blk-mq-sysfs.c blk-mq: add blk_mq_init_allocated_queue and export blk_mq_register_disk 2015-03-13 08:26:53 -06:00
blk-mq-tag.c blkmq: Fix NULL pointer deref when all reserved tags in 2015-03-18 17:06:18 -06:00
blk-mq-tag.h blk-mq: add tag allocation policy 2015-01-23 14:18:00 -07:00
blk-mq.c blk-mq: do limited block plug for multiple queue case 2015-05-08 14:17:21 -06:00
blk-mq.h blk-mq: release mq's kobjects in blk_release_queue() 2015-01-29 08:30:51 -08:00
blk-settings.c block: fix blk_stack_limits() regression due to lcm() change 2015-03-31 09:45:50 -06:00
blk-softirq.c block: fix regression with block enabled tagging 2014-04-09 21:54:06 -06:00
blk-sysfs.c blk-mq: release mq's kobjects in blk_release_queue() 2015-01-29 08:30:51 -08:00
blk-tag.c block: support different tag allocation policy 2015-01-23 14:15:46 -07:00
blk-throttle.c blk-throttle: check stats_cpu before reading it from sysfs 2015-02-20 22:11:58 -08:00
blk-timeout.c blk-mq: Allow requests to never expire 2015-01-08 08:59:01 -07:00
blk.h block: move PM request support to IDE 2015-05-05 13:40:42 -06:00
bounce.c mm: convert some level-less printks to pr_* 2014-06-06 16:08:18 -07:00
bsg-lib.c bsg: Remove unused function bsg_goose_queue() 2012-12-06 14:33:02 +01:00
bsg.c block: Simplify bsg complete all 2015-02-04 09:57:52 -07:00
cfq-iosched.c cfq-iosched: handle failure of cfq group allocation 2015-02-09 10:22:39 -07:00
cmdline-parser.c block: remove unrelated header files and export symbol 2014-01-21 20:18:26 -08:00
compat_ioctl.c block, bdi: an active gendisk always has a request_queue associated with it 2014-09-08 10:00:35 -06:00
deadline-iosched.c block: Stop abusing csd.list for fifo_time 2014-02-24 14:46:32 -08:00
elevator.c block / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM 2014-12-04 01:00:23 +01:00
genhd.c genhd: check for int overflow in disk_expand_part_tbl() 2014-11-19 13:09:07 -07:00
ioctl.c block: Add discard flag to blkdev_issue_zeroout() function 2015-01-21 10:41:46 -07:00
ioprio.c block: Fix computation of merged request priority 2014-10-31 08:30:43 -06:00
noop-iosched.c elevator: Fix a race in elevator switching 2013-07-03 13:25:24 +02:00
partition-generic.c block: Fix dev_t minor allocation lifetime 2014-09-03 15:01:02 -06:00
scsi_ioctl.c sg_io(): use import_iovec() 2015-04-11 22:27:13 -04:00
t10-pi.c block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00