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Date:   Thu, 26 Mar 2020 15:48:55 -0400
From:   Tejun Heo <tj@kernel.org>
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     linux-kernel@vger.kernel.org, Dmitry Shmidt <dimitrysh@google.com>,
        Amit Pundir <amit.pundir@linaro.org>, kernel-team@android.com,
        jsbarnes@google.com, sonnyrao@google.com, vpillai@digitalocean.com,
        peterz@infradead.org, Guenter Roeck <groeck@chromium.org>,
        Waiman Long <longman@redhat.com>,
        Greg Kerr <kerrnel@google.com>, cgroups@vger.kernel.org,
        Johannes Weiner <hannes@cmpxchg.org>,
        Li Zefan <lizefan@huawei.com>
Subject: Re: [PATCH RFC] cpuset: Make cpusets get restored on hotplug
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 <20200326194448.GA133524@google.com>
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On Thu, Mar 26, 2020 at 03:44:48PM -0400, Joel Fernandes wrote:
> It is not really that big a change. Please go over the patch, we are not
> changing anything with how ->cpus_allowed works and interacts with the rest
> of the system and the scheduler. We have just introduced a new mask to keep
> track of which CPUs were requested without them being affected by hotplug. On
> CPU onlining, we restore the state of ->cpus_allowed as not be affected by
> hotplug.

It's not the code. It's the behavior. I'm not flipping the behavior for
the existing cgroup1 users underneath them at this point. As-is, it's a
hard nack. If you really really really want it, put it behind a mount
option.

-- 
tejun