From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug
Date: Mon, 26 Jul 2021 12:59:54 -1000
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 <20210720141834.10624-3-longman@redhat.com>
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To: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>, Shuah Khan <shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>, Phil Auld <pauld-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Juri Lelli <juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Frederic Weisbecker <frederic-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Marcelo Tosatti <mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny-IBi9RG/b67k@public.gmane.org>

On Tue, Jul 20, 2021 at 10:18:27AM -0400, Waiman Long wrote:
> In cpuset_hotplug_workfn(), the detection of whether the cpu list
> has been changed is done by comparing the effective cpus of the top
> cpuset with the cpu_active_mask. However, in the rare case that just
> all the CPUs in the subparts_cpus are offlined, the detection fails
> and the partition states are not updated correctly. Fix it by forcing
> the cpus_updated flag to true in this particular case.
> 
> Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition")
> Signed-off-by: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Applied to cgroup/for-5.15 w/ a minor update to the comment (I dropped
"just" before "all". It read weird to me.)

Thanks.

-- 
tejun