On Tue, Aug 16, 2022, at 11:25 AM, Nikolay Borisov wrote: > On 16.08.22 г. 17:22 ч., Chris Murphy wrote: >> >> >> On Sun, Aug 14, 2022, at 4:28 PM, Chris Murphy wrote: >>> On Fri, Aug 12, 2022, at 2:02 PM, Jens Axboe wrote: >>>> Might be worth trying to revert those from 5.12 to see if they are >>>> causing the issue? Jan, Paolo - does this ring any bells? >>> >>> git log --oneline --no-merges v5.11..c03c21ba6f4e > bisect.txt >>> >>> I tried checking out a33df75c6328, which is right before the first bfq >>> commit, but that kernel won't boot the hardware. >>> >>> Next I checked out v5.12, then reverted these commits in order (that >>> they were found in the bisect.txt file): >>> >>> 7684fbde4516 bfq: Use only idle IO periods for think time calculations >>> 28c6def00919 bfq: Use 'ttime' local variable >>> 41e76c85660c bfq: Avoid false bfq queue merging >>>>>> a5bf0a92e1b8 bfq: bfq_check_waker() should be static >>> 71217df39dc6 block, bfq: make waker-queue detection more robust >>> 5a5436b98d5c block, bfq: save also injection state on queue merging >>> e673914d52f9 block, bfq: save also weight-raised service on queue merging >>> d1f600fa4732 block, bfq: fix switch back from soft-rt weitgh-raising >>> 7f1995c27b19 block, bfq: re-evaluate convenience of I/O plugging on rq arrivals >>> eb2fd80f9d2c block, bfq: replace mechanism for evaluating I/O intensity >>>>>> 1a23e06cdab2 bfq: don't duplicate code for different paths >>> 2391d13ed484 block, bfq: do not expire a queue when it is the only busy >>> one >>> 3c337690d2eb block, bfq: avoid spurious switches to soft_rt of >>> interactive queues >>> 91b896f65d32 block, bfq: do not raise non-default weights >>> ab1fb47e33dc block, bfq: increase time window for waker detection >>> d4fc3640ff36 block, bfq: set next_rq to waker_bfqq->next_rq in waker >>> injection >>> b5f74ecacc31 block, bfq: use half slice_idle as a threshold to check >>> short ttime >>> >>> The two commits prefixed by >>> above were not previously mentioned by >>> Jens, but I reverted them anyway because they showed up in the git log >>> command. >>> >>> OK so, within 10 minutes the problem does happen still. This is >>> block/bfq-iosched.c resulting from the above reverts, in case anyone >>> wants to double check what I did: >>> https://drive.google.com/file/d/1ykU7MpmylJuXVobODWiiaLJk-XOiAjSt/view?usp=sharing >> >> Any suggestions for further testing? I could try go down farther in the bisect.txt list. The problem is if the hardware falls over on an unbootable kernel, I have to bug someone with LOM access. That's a limited resource. >> >> > > 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 Murphy
