linux/block
Josef Bacik 545fbd0775 rq-qos: fix missed wake-ups in rq_qos_throttle
We saw a hang in production with WBT where there was only one waiter in
the throttle path and no outstanding IO.  This is because of the
has_sleepers optimization that is used to make sure we don't steal an
inflight counter for new submitters when there are people already on the
list.

We can race with our check to see if the waitqueue has any waiters (this
is done locklessly) and the time we actually add ourselves to the
waitqueue.  If this happens we'll go to sleep and never be woken up
because nobody is doing IO to wake us up.

Fix this by checking if the waitqueue has a single sleeper on the list
after we add ourselves, that way we have an uptodate view of the list.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-18 10:20:13 -06:00
..
partitions block/partitions/ldm: Convert a kernel-doc header into a non-kernel-doc header 2019-05-31 15:12:34 -06:00
Kconfig Merge branch 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2019-07-08 21:35:12 -07:00
Kconfig.iosched block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG 2019-06-20 10:32:35 -06:00
Makefile block: remove legacy IO schedulers 2018-11-07 13:42:32 -07:00
badblocks.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
bfq-cgroup.c block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG 2019-06-20 10:32:35 -06:00
bfq-iosched.c block, bfq: check also in-flight I/O in dispatch plugging 2019-07-18 07:22:15 -06:00
bfq-iosched.h block, bfq: detect wakers and unconditionally inject their I/O 2019-06-25 09:07:34 -06:00
bfq-wf2q.c block: switch all files cleared marked as GPLv2 or later to SPDX tags 2019-04-30 16:11:59 -06:00
bio-integrity.c block/bio-integrity: fix a memory leak bug 2019-07-11 20:01:21 -06:00
bio.c block: Allow mapping of vmalloc-ed buffers 2019-07-11 20:04:36 -06:00
blk-cgroup.c blkcg: allow blkcg_policy->pd_stat() to print non-debug info too 2019-07-16 10:06:39 -06:00
blk-core.c block: Disable write plugging for zoned block devices 2019-07-10 14:18:01 -06:00
blk-exec.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-flush.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
blk-integrity.c for-5.2/block-20190507 2019-05-07 18:14:36 -07:00
blk-ioc.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-iolatency.c blkcg: allow blkcg_policy->pd_stat() to print non-debug info too 2019-07-16 10:06:39 -06:00
blk-lib.c block: fix 32 bit overflow in __blkdev_issue_discard() 2018-11-14 08:17:18 -07:00
blk-map.c block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
blk-merge.c block: nr_phys_segments needs to be zero for REQ_OP_WRITE_ZEROES 2019-07-03 07:20:40 -06:00
blk-mq-cpumap.c blk-mq: Document the blk_mq_hw_queue_to_node() arguments 2019-05-31 15:12:34 -06:00
blk-mq-debugfs-zoned.c block: Cleanup license notice 2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c for-5.3/block-20190708 2019-07-09 10:45:06 -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: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
blk-mq-sched.h block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
blk-mq-sysfs.c for-5.2/block-20190507 2019-05-07 18:14:36 -07:00
blk-mq-tag.c blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
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 block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq.c block: Disable write plugging for zoned block devices 2019-07-10 14:18:01 -06:00
blk-mq.h block: Disable write plugging for zoned block devices 2019-07-10 14:18:01 -06:00
blk-pm.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-pm.h block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-rq-qos.c rq-qos: fix missed wake-ups in rq_qos_throttle 2019-07-18 10:20:13 -06:00
blk-rq-qos.h block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-settings.c block: force an unlimited segment size on queues with a virt boundary 2019-05-23 10:25:26 -06:00
blk-softirq.c block: remove a few unused exports 2018-11-15 12:13:25 -07:00
blk-stat.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -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: free sched's request pool in blk_cleanup_queue 2019-06-06 22:39:39 -06:00
blk-throttle.c blk-throttle: fix zero wait time for iops throttled group 2019-07-10 09:00:57 -06:00
blk-timeout.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-wbt.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
blk-wbt.h block: remove external dependency on wbt_flags 2018-07-09 09:07:54 -06:00
blk-zoned.c block: Limit zone array allocation size 2019-07-11 20:04:40 -06:00
blk.h block: mark blk_rq_bio_prep as inline 2019-06-20 10:29:22 -06:00
bounce.c block: remove the i argument to bio_for_each_segment_all 2019-04-30 09:26:13 -06:00
bsg-lib.c block: Fix bsg_setup_queue() kernel-doc header 2019-05-31 15:12:34 -06:00
bsg.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -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
elevator.c block: free sched's request pool in blk_cleanup_queue 2019-06-06 22:39:39 -06:00
genhd.c block: fix sysfs module parameters directory path in comment 2019-07-16 10:16:33 -06:00
ioctl.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
ioprio.c block: add SPDX tags to block layer files missing licensing information 2019-04-30 16:12:03 -06:00
kyber-iosched.c blk-mq: remove blk_mq_put_ctx() 2019-07-02 21:03:27 -06:00
mq-deadline.c block: remove the bi_phys_segments field in struct bio 2019-06-20 10:29:22 -06:00
opal_proto.h block: sed-opal: check size of shadow mbr 2019-06-29 10:34:08 -06:00
partition-generic.c block: fix use-after-free on gendisk 2019-04-22 09:48:12 -06:00
scsi_ioctl.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00
sed-opal.c block: sed-opal: check size of shadow mbr 2019-06-29 10:34:08 -06:00
t10-pi.c block: switch all files cleared marked as GPLv2 to SPDX tags 2019-04-30 16:11:57 -06:00