On Tue, Nov 30, 2021 at 10:56:34PM -0500, Waiman Long <longman@redhat.com> wrote:
> > >      A valid parent partition may distribute out all its CPUs to
> > >      its child partitions as long as it is not the root cgroup and
> > >      there is no task associated with it.
> > A valid parent partition which isn't root never has tasks in them to begin
> > with.
> I believe there is some corner cases where it is possible to put task in an
> intermediate partition. That is why I put down this statement.

Just mind the threads -- cpuset controller is threaded and having tasks
in inner cgroup nodes is a real scenario. I wouldn't consider it a
corner case.

[ Actually, the paragraph could IMO be simplified:

> A valid parent partition may distribute out all its CPUs to
> its child partitions as long as there is no task associated with it.

Assuming there's always at least one kernel thread in the root cgroup
that can't be migrated anyway.]


Michal