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From: Qais Yousef <qyousef-wp2msK0BRk8tq7phqP6ubQ@public.gmane.org>
Subject: Re: [PATCH 2/6] sched/cpuset: Bring back cpuset_mutex
Date: Fri, 28 Apr 2023 12:22:16 +0100
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To: Juri Lelli <juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Xuewen Yan <xuewen.yan94-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Hao Luo <haoluo-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Dietmar Eggemann <dietmar.eggemann-5wv7dgnIgG8@public.gmane.org>, Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, luca.abeni-5rdYK369eBLQB0XuIGIEkQ@public.gmane.org, claudio-YOzL5CV4y4YG1A2ADO40+w@public.gmane.org, tommaso.cucinotta-5rdYK369eBLQB0XuIGIEkQ@public.gmane.org, bristot-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mathieu.poirier-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vincent Guittot <vincent.guittot-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Wei Wang <wvw-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Rick Yiu <rickyiu-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Quentin Perret <qperret-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Heiko Carstens <hca-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Vasily Gorbik <gor-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>

On 04/27/23 07:53, Juri Lelli wrote:
> Hi,
> 
> On 27/04/23 10:58, Xuewen Yan wrote:
> > HI Juri,
> > 
> > Would this patch be merged tobe stable-rc? In kernel5.15, we also find
> > that the rwsem would be blocked for a long  time, when we change the
> > task's cpuset cgroup.
> > And when we revert to the mutex, the delay would disappear.
> 
> Honestly, I'm not sure. This change is mostly improving performance, but
> it is also true that it's fixing some priority inheritance corner cases.
> So, I'm not sure it qualifies for stable, but it would be probably good to
> have it there.

I'm under the impression we need the whole lot back to stable, no? I'm not sure
if we can decouple this patch from the rest.

FWIW, I did my testing on 5.15 - so we can definitely help with the backport
and testing for 5.15 and 5.10.


Thanks!