On Sun, Jun 12, 2022 at 05:12:51PM -1000, Tejun Heo <tj@kernel.org> wrote:
> Hello,
> 
> On Sun, Jun 12, 2022 at 11:02:38PM -0400, Waiman Long wrote:
> > That is the behavior enforced by setting the CPU_EXCLUSIVE bit in cgroup v1.
> > I haven't explicitly change it to make it different in cgroup v2. The major
> > reason is that I don't want change to one cpuset to affect a sibling
> > partition as it may make the code more complicate to validate if a partition
> > is valid.
> 
> If at all possible, I'd really like to avoid situations where a parent can't
> withdraw resources due to something that a descendant does.

My understanding of the discussed paragraph is that the changes are only
disallowed only among siblings on one level (due to exclusivity rule,
checked in validate_change()). A change in parent won't affect
(non)exclusivity of (valid) children so it's simply allowed.

So the docs (and implementation by a quick look) is sensible.

Michal