Messages in this thread | | | Subject | Re: stalling IO regression since linux 5.12, through 5.18 | From | Holger Hoffstätte <> | Date | Wed, 17 Aug 2022 11:52:54 +0200 |
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On 2022-08-16 17:34, Chris Murphy wrote: > > On Tue, Aug 16, 2022, at 11:25 AM, Nikolay Borisov wrote: >> How about changing the scheduler either mq-deadline or noop, just >> to see if this is also reproducible with a different scheduler. I >> guess noop would imply the blk cgroup controller is going to be >> disabled > > I already reported on that: always happens with bfq within an hour or > less. Doesn't happen with mq-deadline for ~25+ hours. Does happen > with bfq with the above patches removed. Does happen with > cgroup.disabled=io set. > > Sounds to me like it's something bfq depends on and is somehow > becoming perturbed in a way that mq-deadline does not, and has > changed between 5.11 and 5.12. I have no idea what's under bfq that > matches this description.
Chris, just a shot in the dark but can you try the patch from
https://lore.kernel.org/linux-block/20220803121504.212071-1-yukuai1@huaweicloud.com/
on top of something more recent than 5.12? Ideally 5.19 where it applies cleanly.
No guarantees, I just remembered this patch and your problem sounds like a lost wakeup. Maybe BFQ just drives the sbitmap in a way that triggers the symptom.
-h
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