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Sender: Tejun Heo <htejun@gmail.com>
Date:   Sun, 12 Jun 2022 07:49:55 -1000
From:   Tejun Heo <tj@kernel.org>
To:     Waiman Long <longman@redhat.com>
Cc:     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>,
        Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
Subject: Re: [PATCH v11 7/8] cgroup/cpuset: Update description of
 cpuset.cpus.partition in cgroup-v2.rst
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 <20220510153413.400020-8-longman@redhat.com>
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Hello,

On Tue, May 10, 2022 at 11:34:12AM -0400, Waiman Long wrote:
> +	External events like hotplug or changes to "cpuset.cpus" can
> +	cause a valid partition root to become invalid and vice versa.
> +	Note that a task cannot be moved to a cgroup with empty
> +	"cpuset.cpus.effective".
> +
> +	For a valid partition root or an invalid partition root with
> +	the exclusivity rule enabled, changes made to "cpuset.cpus"
> +	that violate the exclusivity rule will not be allowed.

My memory is failing but this is the same thing that we were discussing
before, right? The point was that the different behaviors re. system events
and config actions seemed unncessary and IIRC Michal was of the same opinion
(please correct me if I'm misremembering).

> +	A valid non-root parent partition may distribute out all its CPUs
> +	to its child partitions when there is no task associated with it.

I'm probably forgetting something. Was this necessary because of threaded
cgroup support because otherwise the above condition is superflous?

Thanks.

-- 
tejun