From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Subject: Re: [RFC PATCH 0/2] cpuset: Skip possible unwanted CPU-mask updates.
Date: Fri, 11 Nov 2022 16:34:08 +0100
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To: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>

On 2022-11-02 09:20:48 [-0400], Waiman Long wrote:
Hi,

> Yes, that is a known issue which is especially problematic when cgroup v2 is
> used. That is why I have recently posted a set of patches to enable
> persistent user requested affinity and they have been merged into tip:
> 
> 851a723e45d1 sched: Always clear user_cpus_ptr in do_set_cpus_allowed()
> da019032819a sched: Enforce user requested affinity
> 8f9ea86fdf99 sched: Always preserve the user requested cpumask
> 713a2e21a513 sched: Introduce affinity_context
> 5584e8ac2c68 sched: Add __releases annotations to affine_move_task()

> They should be able to address the problem that you list here. Please let me
> know if there are still problem remaining.

Thank you. This solves the most pressing issue. The CPU-mask is still
reset upon activation of the cpuset controller.
This is due to the set_cpus_allowed_ptr() in cpuset_attach().

Is is possible to push these patches stable?

> Thanks,
> Longman

Sebastian