Paolo Valente 2391d13ed4 block, bfq: do not expire a queue when it is the only busy one ... This commits preserves I/O-dispatch plugging for a special symmetric case that may suddenly turn into asymmetric: the case where only one bfq_queue, say bfqq, is busy. In this case, not expiring bfqq does not cause any harm to any other queues in terms of service guarantees. In contrast, it avoids the following unlucky sequence of events: (1) bfqq is expired, (2) a new queue with a lower weight than bfqq becomes busy (or more queues), (3) the new queue is served until a new request arrives for bfqq, (4) when bfqq is finally served, there are so many requests of the new queue in the drive that the pending requests for bfqq take a lot of time to be served. In particular, event (2) may case even already dispatched requests of bfqq to be delayed, inside the drive. So, to avoid this series of events, the scenario is preventively declared as asymmetric also if bfqq is the only busy queues. By doing so, I/O-dispatch plugging is performed for bfqq. Tested-by: Jan Kara <jack@suse.cz> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2021-01-24 18:18:24 -07:00
..
partitions	block: use an xarray for disk->part_tbl	2021-01-24 18:17:20 -07:00
badblocks.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
bfq-cgroup.c	bfq: fix blkio cgroup leakage v4	2020-08-18 07:48:08 -07:00
bfq-iosched.c	block, bfq: do not expire a queue when it is the only busy one	2021-01-24 18:18:24 -07:00
bfq-iosched.h	bfq: fix blkio cgroup leakage v4	2020-08-18 07:48:08 -07:00
bfq-wf2q.c	bfq: fix blkio cgroup leakage v4	2020-08-18 07:48:08 -07:00
bio-integrity.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
bio.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
blk-cgroup-rwstat.c	blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT	2019-11-07 12:28:13 -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	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
blk-core.c	blk-mq: use ->bi_bdev for I/O accounting	2021-01-24 18:17:20 -07:00
blk-crypto-fallback.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -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	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
blk-exec.c	block: add a blk_account_io_merge_bio helper	2020-05-27 05:21:23 -06:00
blk-flush.c	for-5.11/block-2020-12-14	2020-12-16 12:57:51 -08:00
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 NULL iocg deref from racing against initialization	2021-01-05 11:33:32 -07:00
blk-iolatency.c	block: Remove redundant 'return' statement	2020-10-08 07:59:48 -06:00
blk-lib.c	block: move the start_sect field to struct block_device	2020-12-01 14:53:40 -07:00
blk-map.c	block: fix bmd->is_null_mapped initialization	2020-09-23 09:18:39 -06:00
blk-merge.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
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	block-5.11-2021-01-10	2021-01-10 12:53:08 -08:00
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	block: remove the request_queue to argument request based tracepoints	2020-12-04 09:42:00 -07:00
blk-mq-sched.h	block-5.10-2020-10-12	2020-10-13 12:12:44 -07:00
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	block-mq: fix comments in blk_mq_queue_tag_busy_iter	2020-09-29 08:11:00 -06:00
blk-mq-tag.h	blk-mq: Relocate hctx_may_queue()	2020-09-03 15:20:47 -06:00
blk-mq-virtio.c	blk-mq: Fix typo in comment	2020-03-17 20:55:21 +01:00
blk-mq.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
blk-mq.h	blk-mq: update arg in comment of blk_mq_map_queue	2020-12-12 11:13:41 -07:00
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	scsi: block: Do not accept any requests while suspended	2020-12-09 11:41:42 -05:00
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: use an xarray for disk->part_tbl	2021-01-24 18:17:20 -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	blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue	2020-10-09 12:46:28 -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	block: wbt: Remove unnecessary invoking of wbt_update_limits in wbt_init	2020-11-30 15:01:18 -07:00
blk-wbt.h	blk-wbt: remove wbt_update_limits	2020-05-29 16:30:39 -06:00
blk-zoned.c	block: Improve blk_revalidate_disk_zones() checks	2020-12-07 17:34:21 -07:00
blk.h	block: use an xarray for disk->part_tbl	2021-01-24 18:17:20 -07:00
bounce.c	block: store a block_device pointer in struct bio	2021-01-24 18:17:20 -07:00
bsg-lib.c	block: drop double zeroing	2020-09-23 09:18:13 -06:00
bsg.c	compat_ioctl: bsg: add handler	2020-01-03 09:33:21 +01:00
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	block: fix comment and add lockdep assert	2020-10-09 12:34:06 -06:00
genhd.c	block: use an xarray for disk->part_tbl	2021-01-24 18:17:20 -07:00
ioctl.c	block: move the policy field to struct block_device	2020-12-01 14:53:40 -07:00
ioprio.c	block: grant IOPRIO_CLASS_RT to CAP_SYS_NICE	2020-09-01 19:38:33 -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	block/keyslot-manager: prevent crash when num_slots=1	2020-11-20 11:52:52 -07:00
kyber-iosched.c	blk-mq: Use pointers for blk_mq_tags bitmap tags	2020-09-03 15:20:47 -06:00
Makefile	blk-mq: merge blk-softirq.c into blk-mq.c	2020-06-24 09:15:56 -06:00
mq-deadline.c	blk-mq, elevator: Count requests per hctx to improve performance	2020-09-03 15:20:47 -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	drivers-5.10-2020-10-12	2020-10-13 13:04:41 -07:00
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