Re: [PATCH BUGFIX] block, bfq: deschedule empty bfq_queues not referred by any process

Oleksandr Natalenko
2019-11-13T14:25:19Z

On 13.11.2019 14:52, Paolo Valente wrote:
>> I'm not sure if I see things right, but this commit along with v5.3.11
>> kernel causes almost all boots to hang (for instance, on mounting the
>> FS). Once the scheduler is changed to something else than BFQ (I set
>> the I/O scheduler early via udev rule), multiple reboots go just fine.
>>
>
> If you switch back to bfq after the boot, can you still reproduce the
> hang?

I didn't try to switch schedulers, but what I see now is once the system
is able to boot with BFQ, the I/O can still hang on I/O burst (which for
me happens to happen during VM reboot).

This may also not hang forever, but just slow down considerably. I've
noticed this inside a KVM VM, not on a real HW.

>> Is this commit also applicable to 5.3 kernels?
>
> It is.

OK, thanks for clarification.

--
Oleksandr Natalenko (post-factum)