Re: [PATCH 2/2] cgroup: Skip subtree root in cgroup_update_dfl_csses()

[Waiman Long]

On 7/28/22 10:44, Michal Koutný wrote:
> On Wed, Jul 27, 2022 at 08:58:15PM -0400, Waiman Long <longman@xxxxxxxxxx> wrote:
> > The cgroup_update_dfl_csses() function updates css associations when a
> > cgroup's subtree_control file is modified. Any changes made to a cgroup's
> > subtree_control file, however, will only affect its descendants but not
> > the cgroup itself.
> I find this correct.
>
> > So there is no point in migrating csses associated with that cgroup.
> > We can skip them instead.
> Alone it's not such a big win but it componds with the recent Tejun's
> threadgroup_rwsem elision.
It is more an optimization patch trying to not waste cpu time doing 
unnecessary work.
> > ---
> >   kernel/cgroup/cgroup.c | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> Feel free to have
> Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Thanks for the review.

Cheers,
Longman