linux/block
John Garry d97e594c51 blk-mq: Use request queue-wide tags for tagset-wide sbitmap
The tags used for an IO scheduler are currently per hctx.

As such, when q->nr_hw_queues grows, so does the request queue total IO
scheduler tag depth.

This may cause problems for SCSI MQ HBAs whose total driver depth is
fixed.

Ming and Yanhui report higher CPU usage and lower throughput in scenarios
where the fixed total driver tag depth is appreciably lower than the total
scheduler tag depth:
https://lore.kernel.org/linux-block/440dfcfc-1a2c-bd98-1161-cec4d78c6dfc@huawei.com/T/#mc0d6d4f95275a2743d1c8c3e4dc9ff6c9aa3a76b

In that scenario, since the scheduler tag is got first, much contention
is introduced since a driver tag may not be available after we have got
the sched tag.

Improve this scenario by introducing request queue-wide tags for when
a tagset-wide sbitmap is used. The static sched requests are still
allocated per hctx, as requests are initialised per hctx, as in
blk_mq_init_request(..., hctx_idx, ...) ->
set->ops->init_request(.., hctx_idx, ...).

For simplicity of resizing the request queue sbitmap when updating the
request queue depth, just init at the max possible size, so we don't need
to deal with the possibly with swapping out a new sbitmap for old if
we need to grow.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1620907258-30910-3-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24 06:47:22 -06:00
..
partitions block/partitions/efi.c: Fix the efi_partition() kernel-doc header 2021-05-14 09:00:06 -06:00
badblocks.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
bfq-cgroup.c block, bfq: merge bursts of newly-created queues 2021-03-25 10:50:07 -06:00
bfq-iosched.c block, bfq: avoid circular stable merges 2021-05-12 07:39:23 -06:00
bfq-iosched.h block, bfq: merge bursts of newly-created queues 2021-03-25 10:50:07 -06:00
bfq-wf2q.c block, bfq: always inject I/O of queues blocked by wakers 2021-03-25 10:50:07 -06:00
bio-integrity.c block: remove BLK_BOUNCE_ISA support 2021-04-06 09:28:17 -06:00
bio.c Revert "bio: limit bio max size" 2021-05-08 21:49:48 -06:00
blk-cgroup-rwstat.c blk-cgroup: Fix the recursive blkg rwstat 2021-03-05 11:32:15 -07:00
blk-cgroup-rwstat.h blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT 2019-11-07 12:28:13 -07:00
blk-cgroup.c blkcg: drop CLONE_IO check in blkcg_can_attach() 2021-05-24 06:47:21 -06:00
blk-core.c block_dump: remove block_dump feature 2021-05-24 06:47:21 -06:00
blk-crypto-fallback.c block: rename BIO_MAX_PAGES to BIO_MAX_VECS 2021-03-11 07:47:48 -07:00
blk-crypto-internal.h block: make blk_crypto_rq_bio_prep() able to fail 2020-10-05 10:47:43 -06:00
blk-crypto.c dm: support key eviction from keyslot managers of underlying devices 2021-02-11 09:45:25 -05:00
blk-exec.c block: drop removed argument from kernel-doc of blk_execute_rq() 2021-01-29 07:43:29 -07:00
blk-flush.c block: avoid double io accounting for flush request 2021-05-24 06:47:21 -06:00
blk-integrity.c block: remove the unused blk_integrity_merge_bio export 2020-10-06 07:29:53 -06:00
blk-ioc.c block: remove retry loop in ioc_release_fn() 2020-07-16 10:22:15 -06:00
blk-iocost.c blk-iocost: fix weight updates of inner active iocgs 2021-05-11 20:50:35 -06:00
blk-iolatency.c block: Remove redundant 'return' statement 2020-10-08 07:59:48 -06:00
blk-lib.c block: rename BIO_MAX_PAGES to BIO_MAX_VECS 2021-03-11 07:47:48 -07:00
blk-map.c block: remove an incorrect check from blk_rq_append_bio 2021-04-12 06:45:12 -06:00
blk-merge.c block: recalculate segment count for multi-segment discards correctly 2021-03-23 10:39:57 -06:00
blk-mq-cpumap.c blk-mq: remove the calling of local_memory_node() 2020-10-20 07:08:17 -06:00
blk-mq-debugfs-zoned.c block: Cleanup license notice 2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c for-5.13/block-2021-04-27 2021-04-28 14:27:12 -07:00
blk-mq-debugfs.h blk-mq: no need to check return value of debugfs_create functions 2019-06-13 03:00:30 -06:00
blk-mq-pci.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-rdma.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-sched.c blk-mq: Use request queue-wide tags for tagset-wide sbitmap 2021-05-24 06:47:22 -06:00
blk-mq-sched.h blk-mq: Use request queue-wide tags for tagset-wide sbitmap 2021-05-24 06:47:22 -06:00
blk-mq-sysfs.c blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue 2020-10-09 12:46:28 -06:00
blk-mq-tag.c blk-mq: Use request queue-wide tags for tagset-wide sbitmap 2021-05-24 06:47:22 -06:00
blk-mq-tag.h blk-mq: Some tag allocation code refactoring 2021-05-24 06:47:22 -06:00
blk-mq-virtio.c blk-mq: Fix typo in comment 2020-03-17 20:55:21 +01:00
blk-mq.c blk-mq: Use request queue-wide tags for tagset-wide sbitmap 2021-05-24 06:47:22 -06:00
blk-mq.h blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter 2021-05-24 06:47:22 -06:00
blk-pm.c scsi: block: Fix a race in the runtime power management code 2020-12-09 11:41:41 -05:00
blk-pm.h block: Remove unused blk_pm_*() function definitions 2021-02-22 06:33:48 -07:00
blk-rq-qos.c Revert "blk-rq-qos: remove redundant finish_wait to rq_qos_wait." 2020-07-15 09:33:37 -06:00
blk-rq-qos.h blk-rq-qos: fix first node deletion of rq_qos_del() 2019-10-15 10:13:13 -06:00
blk-settings.c block-5.13-2021-05-09 2021-05-09 13:25:14 -07:00
blk-stat.c blk-stat: make q->stats->lock irqsafe 2020-09-01 16:48:46 -06:00
blk-stat.h block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-sysfs.c block: remove unneeded parenthesis from blk-sysfs 2021-05-24 06:47:21 -06:00
blk-throttle.c block: store a block_device pointer in struct bio 2021-01-24 18:17:20 -07:00
blk-timeout.c block: blk-timeout: delete duplicated word 2020-07-31 16:29:47 -06:00
blk-wbt.c blk: wbt: remove unused parameter from wbt_should_throttle 2021-01-26 13:13:00 -07:00
blk-wbt.h blk-wbt: remove wbt_update_limits 2020-05-29 16:30:39 -06:00
blk-zoned.c blk-zoned: Remove the definition of blk_zone_start() 2021-04-07 14:31:45 -06:00
blk.h block: refactor blk_drop_partitions 2021-04-08 10:24:36 -06:00
bounce.c block: stop calling blk_queue_bounce for passthrough requests 2021-04-06 09:28:18 -06:00
bsg-lib.c block: drop double zeroing 2020-09-23 09:18:13 -06:00
bsg.c block: remove unnecessary argument from blk_execute_rq 2021-01-24 21:52:39 -07:00
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
elevator.c blk-mq: set default elevator as deadline in case of hctx shared tagset 2021-04-07 10:15:23 -06:00
genhd.c block: prevent block device lookups at the beginning of del_gendisk 2021-05-20 07:59:35 -06:00
ioctl.c block: return -EBUSY when there are open partitions in blkdev_reread_part 2021-04-21 10:49:37 -06:00
ioprio.c block: Fix sys_ioprio_set(.which=IOPRIO_WHO_PGRP) task iteration 2021-04-08 13:43:53 -06:00
Kconfig blk-wbt: Remove obsolete multiqueue I/O scheduling comment 2020-09-01 16:49:26 -06:00
Kconfig.iosched treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
keyslot-manager.c - Fix DM integrity's HMAC support to provide enhanced security of 2021-02-22 10:22:54 -08:00
kyber-iosched.c kyber: fix out of bounds access when preempted 2021-05-11 08:12:14 -06:00
Makefile blk-mq: merge blk-softirq.c into blk-mq.c 2020-06-24 09:15:56 -06:00
mq-deadline.c kyber: fix out of bounds access when preempted 2021-05-11 08:12:14 -06:00
opal_proto.h block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
scsi_ioctl.c block: Remove an obsolete comment from sg_io() 2021-04-13 11:23:52 -06:00
sed-opal.c block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
t10-pi.c block: Allow t10-pi to be modular 2020-01-06 20:59:04 -07:00