Re: [PATCH BUGFIX/IMPROVEMENT 0/4] bfq: two fixes and one improvement related to I/O control

From: Jens Axboe
Date: Thu Aug 16 2018 - 15:10:07 EST


On 8/16/18 10:51 AM, Paolo Valente wrote:
> Hi Jens,
>
> while working a little bit on cgroups I/O control, I found two nasty
> bugs in bfq. They break bandwidth control in simple configurations
> with one-process groups. These bugs are fixed by the first two patches
> in this series.
>
> These fixes improved I/O control so much, that I could reduce the
> write overcharge factor, used by bfq to counter write-induced
> issues. This reduction is performed by the third patch.
>
> The fourth patch contains a little code improvement I made in a
> function that has to do with I/O control.
>
> I hope we are still in time for 4.19.

Patches look fine to me. You are in fact several weeks late for 4.19, I
need to have anything that's going in to 4.19 by -rc6 or -rc7 time
(depending on whether we have an -rc8 or not). This is to ensure that it
gets plenty of time in linux-next as well. I've queued up patches this
time (since they were small), but please send them in in due time next
time.

--
Jens Axboe