Sender: Tejun Heo <htejun@gmail.com>
Date:   Wed, 1 Dec 2021 06:39:34 -1000
From:   Tejun Heo <tj@kernel.org>
To:     Waiman Long <longman@redhat.com>
Cc:     Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>,
        Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Shuah Khan <shuah@kernel.org>, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Roman Gushchin <guro@fb.com>, Phil Auld <pauld@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v8 5/6] cgroup/cpuset: Update description of
 cpuset.cpus.partition in cgroup-v2.rst
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On Wed, Dec 01, 2021 at 09:56:21AM -0500, Waiman Long wrote:
> Right, I shouldn't say corner cases. Having task in an intermediate
> partition is possible depending on event sequence. I am aware that there are
> code in the cpuset code to prevent that, but it didn't block all cases.
> > > 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.]
> 
> I am aware of that. That is why I said root cgroup must have at least one
> cpu in its "cpuset.cpus.effective".

In that case, let's explicitly describe that condition.

Thanks.

-- 
tejun