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

[Oleksandr Natalenko]

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)