Re: stalling IO regression since linux 5.12, through 5.18

[Ming Lei]

Hello Chris,

On Tue, Aug 16, 2022 at 11:35 PM Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote:
>
>
>
...
>
> 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.
>

blk-mq debugfs log is usually helpful for io stall issue, care to post
the blk-mq debugfs log:

(cd /sys/kernel/debug/block/$disk && find . -type f -exec grep -aH . {} \;)

Thanks,
Ming