The commit is pushed to "branch-rh7-3.10.0-1160.76.1.vz7.189.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.76.1.vz7.189.4
------>
commit 729c880e01c9a40b96e6cbfdf49bf928c74e59fb
Author: Josef Bacik <jo...@toxicpanda.com>
Date: Thu Sep 29 14:30:10 2022 +0300
ms/rq-qos: don't reset has_sleepers on spurious wakeups
If we raced with somebody else getting an inflight counter we could fail
to get an inflight counter with no sleepers on the list, and thus need
to go to sleep. In this case has_sleepers should be true because we are
now relying on the waker to get our inflight counter for us. And in the
case of spurious wakeups we'd still want this to be the case. So set
has_sleepers to true if we went to sleep to make sure we're woken up the
proper way.
Reviewed-by: Oleg Nesterov <o...@redhat.com>
Signed-off-by: Josef Bacik <jo...@toxicpanda.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Changes when porting to vz7:
- original patch is patching block/blk-rq-qos.c:rq_qos_wait, but in vz7
similar hunk is in block/blk-wbt.c:__wbt_wait
https://jira.sw.ru/browse/PSBM-141883
(cherry picked from commit 64e7ea875ef63b2801be7954cf7257d1bfccc266)
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
=================
Patchset description:
blk-wbt: Fix hardlockup in wbt_done()
We have a hard lockup detected in this stack:
#13 [ffff9103fe603af8] __enqueue_entity at ffffffffb8ce64c5
#14 [ffff9103fe603b00] enqueue_entity at ffffffffb8cee27a
#15 [ffff9103fe603b50] enqueue_task_fair at ffffffffb8ceea9c
#16 [ffff9103fe603ba0] activate_task at ffffffffb8cdd029
#17 [ffff9103fe603bc8] ttwu_do_activate at ffffffffb8cdd491
#18 [ffff9103fe603bf0] try_to_wake_up at ffffffffb8ce124a
#19 [ffff9103fe603c40] default_wake_function at ffffffffb8ce1552
#20 [ffff9103fe603c50] autoremove_wake_function at ffffffffb8ccb178
#21 [ffff9103fe603c78] __wake_up_common at ffffffffb8cd7752
#22 [ffff9103fe603cd0] __wake_up_common_lock at ffffffffb8cd7873
#23 [ffff9103fe603d40] __wake_up at ffffffffb8cd78c3
#24 [ffff9103fe603d50] __wbt_done at ffffffffb8fb6573
#25 [ffff9103fe603d60] wbt_done at ffffffffb8fb65f2
#26 [ffff9103fe603d80] __blk_mq_finish_request at ffffffffb8f8daa1
#27 [ffff9103fe603db8] blk_mq_finish_request at ffffffffb8f8db6a
#28 [ffff9103fe603dc8] blk_mq_sched_put_request at ffffffffb8f93ee0
#29 [ffff9103fe603de8] blk_mq_end_request at ffffffffb8f8d1a4
#30 [ffff9103fe603e08] nvme_complete_rq at ffffffffc033dcfc [nvme_core]
#31 [ffff9103fe603e18] nvme_pci_complete_rq at ffffffffc038be70 [nvme]
#32 [ffff9103fe603e40] __blk_mq_complete_request at ffffffffb8f8d316
#33 [ffff9103fe603e68] blk_mq_complete_request at ffffffffb8f8d3c7
#34 [ffff9103fe603e78] nvme_irq at ffffffffc038c0b2 [nvme]
#35 [ffff9103fe603eb0] __handle_irq_event_percpu at ffffffffb8d66bb4
#36 [ffff9103fe603ef8] handle_irq_event_percpu at ffffffffb8d66d62
#37 [ffff9103fe603f28] handle_irq_event at ffffffffb8d66dec
#38 [ffff9103fe603f50] handle_edge_irq at ffffffffb8d69c0f
#39 [ffff9103fe603f70] handle_irq at ffffffffb8c30524
#40 [ffff9103fe603fb8] do_IRQ at ffffffffb93d898d
which is exactly the same as ubuntu problem here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1810998
this is because we have writeback throttling ported which does not work
well in some cases.
In launchpad bug it helped to port these patches from mainstream:
* CPU hard lockup with rigorous writes to NVMe drive (LP: #1810998)
- blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait
- blk-wbt: move disable check into get_limit()
- blk-wbt: use wq_has_sleeper() for wq active check
- blk-wbt: fix has-sleeper queueing check
- blk-wbt: abstract out end IO completion handler
- blk-wbt: improve waking of tasks
which fixes similar lockup issues in wbt.
More over I've found some more small and useful patches which fix races
(missed wakeups) in this code, so I've also put them in the patchset.
Anchal Agarwal (1):
blk-wbt: Avoid lock contention and thundering herd issue in wbt_wait
Herbert Xu (1):
net: Generalise wq_has_sleeper helper
Jens Axboe (5):
blk-wbt: move disable check into get_limit()
blk-wbt: use wq_has_sleeper() for wq active check
blk-wbt: fix has-sleeper queueing check
blk-wbt: abstract out end IO completion handler
blk-wbt: improve waking of tasks
Josef Bacik (5):
wait: add wq_has_single_sleeper helper
rq-qos: fix missed wake-ups in rq_qos_throttle
rq-qos: don't reset has_sleepers on spurious wakeups
rq-qos: set ourself TASK_UNINTERRUPTIBLE after we schedule
rq-qos: use a mb for got_token
https://jira.sw.ru/browse/PSBM-141883
Ported-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
---
block/blk-wbt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 5477c3ffe7a7..f3c0841f009a 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -598,7 +598,7 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags
wb_acct,
if (lock)
spin_lock_irq(lock);
- has_sleeper = false;
+ has_sleeper = true;
} while (1);
finish_wait(&rqw->wait, &data.wq);
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