Re: [PATCH v8 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst

From: Michal Koutný
Date: Wed Dec 01 2021 - 09:13:56 EST


On Tue, Nov 30, 2021 at 10:56:34PM -0500, Waiman Long <longman@xxxxxxxxxx> 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

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