Re: [RFC PATCH-cgroup 5/6] cgroup: Skip dying css in cgroup_apply_control_{enable,disable}

From: Tejun Heo
Date: Wed Jun 21 2017 - 18:05:00 EST


On Wed, Jun 21, 2017 at 06:01:56PM -0400, Waiman Long wrote:
> I do think that it can happen with existing code because CSS killing is
> asynchronous, I think. So the command can complete before the CSS is
> actually gone. If the next command to reactivate it happens fast enough,
> we can trigger that. When I added more checking to my test script
> essentially increasing the latency between successive tests, I couldn't
> trigger it anymore.

While disabling is asynchronous, there's a flushing logic before
starting reenabling things, so the existing code shouldn't trigger
that condition. But then there's should and the reality. :)