Re: [PATCH v3 cgroup/for-5.20] cgroup: Replace cgroup->ancestor_ids[] with ->ancestors[]

Namhyung Kim
2022-09-22T04:05:20Z

Hi Tejun,

On Mon, Aug 15, 2022 at 2:17 PM Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>
> On Fri, Jul 29, 2022 at 01:10:16PM -1000, Tejun Heo wrote:
> > Every cgroup knows all its ancestors through its ->ancestor_ids[]. There's
> > no advantage to remembering the IDs instead of the pointers directly and
> > this makes the array useless for finding an actual ancestor cgroup forcing
> > cgroup_ancestor() to iteratively walk up the hierarchy instead. Let's
> > replace cgroup->ancestor_ids[] with ->ancestors[] and remove the walking-up
> > from cgroup_ancestor().
> >
> > While at it, improve comments around cgroup_root->cgrp_ancestor_storage.
> >
> > This patch shouldn't cause user-visible behavior differences.
> >
> > v2: Update cgroup_ancestor() to use ->ancestors[].
> >
> > v3: cgroup_root->cgrp_ancestor_storage's type is updated to match
> > cgroup->ancestors[]. Better comments.
> >
> > Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > Acked-by: Namhyung Kim <namhyung-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>
> Applied to cgroup/for-6.1.

I've realized that perf stat change needs backward compatibility.
Will send a fix soon.

Thanks,
Namhyung