Re: [PATCH -next 2/4] blk-iocost: don't throttle bio if iocg is offlined

[Tejun Heo]

On Sat, Dec 17, 2022 at 11:05:25AM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
> 
> bio will grab blkg reference, however, blkcg->online_pin is not grabbed,
> hence cgroup can be removed after thread exit while bio is still in
> progress. Bypass io in this case since it doesn't make sense to
> throttle bio while cgroup is removed.

I don't get it. Why wouldn't that make sense? ISTR some occasions where we
clear the config to mitigate exits stalling for too long but in general a
policy being active on a draining cgroup shouldn't be a problem.

Thanks.

-- 
tejun