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Ming Lei 6ce3dd6eec blk-mq: issue directly if hw queue isn't busy in case of 'none'
In case of 'none' io scheduler, when hw queue isn't busy, it isn't
necessary to enqueue request to sw queue and dequeue it from
sw queue because request may be submitted to hw queue asap without
extra cost, meantime there shouldn't be much request in sw queue,
and we don't need to worry about effect on IO merge.

There are still some single hw queue SCSI HBAs(HPSA, megaraid_sas, ...)
which may connect high performance devices, so 'none' is often required
for obtaining good performance.

This patch improves IOPS and decreases CPU unilization on megaraid_sas,
per Kashyap's test.

Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Reported-by: Kashyap Desai <kashyap.desai@broadcom.com>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-17 16:04:00 -06:00
..
partitions partitions/ldm: remove redundant pointer dgrp 2018-07-09 09:07:53 -06:00
Kconfig block: introduce blk-iolatency io controller 2018-07-09 09:07:54 -06:00
Kconfig.iosched License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile block: introduce blk-iolatency io controller 2018-07-09 09:07:54 -06:00
badblocks.c badblocks: fix wrong return value in badblocks_set if badblocks are disabled 2017-11-03 11:29:50 -07:00
bfq-cgroup.c block: use ktime_get_ns() instead of sched_clock() for cfq and bfq 2018-05-09 08:33:06 -06:00
bfq-iosched.c block, bfq: give a better name to bfq_bfqq_may_idle 2018-07-09 09:07:52 -06:00
bfq-iosched.h block, bfq: add/remove entity weights correctly 2018-07-09 09:07:52 -06:00
bfq-wf2q.c block, bfq: fix service being wrongly set to zero in case of preemption 2018-07-09 09:07:52 -06:00
bio-integrity.c block: Convert bio_set to mempool_init() 2018-05-14 13:16:03 -06:00
bio.c rq-qos: introduce dio_bio callback 2018-07-09 09:07:54 -06:00
blk-cgroup.c block: introduce blk-iolatency io controller 2018-07-09 09:07:54 -06:00
blk-core.c block: Add default switch case to blk_pm_allow_request() to kill warning 2018-07-09 09:07:54 -06:00
blk-exec.c blk-mq-sched: remove unused 'can_block' arg from blk_mq_sched_insert_request 2018-01-17 09:49:21 -07:00
blk-flush.c block: fix use-after-free in block flush handling 2018-06-09 06:37:14 -06:00
blk-integrity.c block drivers/block: Use octal not symbolic permissions 2018-05-24 13:38:59 -06:00
blk-ioc.c block, mm: remove unnecessary __GFP_HIGH flag 2018-07-09 09:07:54 -06:00
blk-iolatency.c blk-iolatency: truncate our current time 2018-07-16 10:15:19 -06:00
blk-lib.c block: fix infinite loop if the device loses discard capability 2018-07-09 09:07:54 -06:00
blk-map.c Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-block 2018-01-29 11:51:49 -08:00
blk-merge.c block: don't use blocking queue entered for recursive bio submits 2018-06-02 20:35:00 -06:00
blk-mq-cpumap.c blk-mq: don't keep offline CPUs mapped to hctx 0 2018-04-10 08:38:46 -06:00
blk-mq-debugfs-zoned.c block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n 2018-07-09 09:07:52 -06:00
blk-mq-debugfs.c blk-mq: dequeue request one by one from sw queue if hctx is busy 2018-07-09 09:07:53 -06:00
blk-mq-debugfs.h block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n 2018-07-09 09:07:52 -06:00
blk-mq-pci.c blk-mq: code clean-up by adding an API to clear set->mq_map 2018-07-09 09:07:53 -06:00
blk-mq-rdma.c block: Add rdma affinity based queue mapping helper 2017-08-08 14:58:03 -04:00
blk-mq-sched.c blk-mq: issue directly if hw queue isn't busy in case of 'none' 2018-07-17 16:04:00 -06:00
blk-mq-sched.h block: move sysfs_lock into elevator_init 2018-06-01 07:38:19 -06:00
blk-mq-sysfs.c block drivers/block: Use octal not symbolic permissions 2018-05-24 13:38:59 -06:00
blk-mq-tag.c blk-mq: remove blk_mq_tagset_iter 2018-06-14 17:01:45 +02:00
blk-mq-tag.h Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
blk-mq-virtio.c blk-mq: provide a default queue mapping for virtio device 2017-02-27 20:54:05 +02:00
blk-mq.c blk-mq: issue directly if hw queue isn't busy in case of 'none' 2018-07-17 16:04:00 -06:00
blk-mq.h blk-mq: issue directly if hw queue isn't busy in case of 'none' 2018-07-17 16:04:00 -06:00
blk-rq-qos.c rq-qos: introduce dio_bio callback 2018-07-09 09:07:54 -06:00
blk-rq-qos.h rq-qos: introduce dio_bio callback 2018-07-09 09:07:54 -06:00
blk-settings.c blk-rq-qos: refactor out common elements of blk-wbt 2018-07-09 09:07:54 -06:00
blk-softirq.c block: fix timeout changes for legacy request drivers 2018-06-19 11:27:18 -06:00
blk-stat.c blk-stat: export helpers for modifying blk_rq_stat 2018-07-09 09:07:54 -06:00
blk-stat.h blk-stat: export helpers for modifying blk_rq_stat 2018-07-09 09:07:54 -06:00
blk-sysfs.c blk-rq-qos: refactor out common elements of blk-wbt 2018-07-09 09:07:54 -06:00
blk-tag.c for-linus-20180616 2018-06-17 05:37:55 +09:00
blk-throttle.c block: add bi_blkg to the bio for cgroups 2018-07-09 09:07:53 -06:00
blk-timeout.c blk-mq: Fix timeout handling in case the timeout handler returns BLK_EH_DONE 2018-06-23 10:25:45 -06:00
blk-wbt.c block: remove external dependency on wbt_flags 2018-07-09 09:07:54 -06:00
blk-wbt.h block: remove external dependency on wbt_flags 2018-07-09 09:07:54 -06:00
blk-zoned.c block: Remove a superfluous cast from blkdev_report_zones() 2018-07-09 09:07:52 -06:00
blk.h block: introduce blk-iolatency io controller 2018-07-09 09:07:54 -06:00
bounce.c block: fixup bioset_integrity_create() call 2018-05-30 18:51:21 -06:00
bsg-lib.c block: remove parent device reference from struct bsg_class_device 2018-05-29 13:00:25 -06:00
bsg.c bsg: remove read/write support 2018-07-12 08:04:08 -06:00
cfq-iosched.c block drivers/block: Use octal not symbolic permissions 2018-05-24 13:38:59 -06:00
cmdline-parser.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_ioctl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
deadline-iosched.c block drivers/block: Use octal not symbolic permissions 2018-05-24 13:38:59 -06:00
elevator.c block: split the blk-mq case from elevator_init 2018-06-01 07:38:21 -06:00
genhd.c Merge branch 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 10:00:01 -07:00
ioctl.c block: pass inclusive 'lend' parameter to truncate_inode_pages_range 2018-02-23 15:20:19 -07:00
ioprio.c block: add ioprio_check_cap function 2018-05-31 10:50:54 -04:00
kyber-iosched.c block: kyber: make kyber more friendly with merging 2018-05-30 10:47:40 -06:00
mq-deadline.c block drivers/block: Use octal not symbolic permissions 2018-05-24 13:38:59 -06:00
noop-iosched.c block: move existing elevator ops to union 2017-01-17 10:03:33 -07:00
opal_proto.h block: sed-opal: Set MBRDone on S3 resume path if TPER is MBREnabled 2017-09-11 09:45:52 -06:00
partition-generic.c block: don't print a message when the device went away 2018-05-29 08:59:21 -06:00
scsi_ioctl.c block: consistently use GFP_NOIO instead of __GFP_NORECLAIM 2018-05-14 08:55:18 -06:00
sed-opal.c block: sed-opal: Fix a couple off by one bugs 2018-06-20 12:04:06 -06:00
t10-pi.c t10-pi: Move opencoded contants to common header 2017-07-03 16:56:25 -06:00