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Sender: Tejun Heo <htejun@gmail.com>
Date:   Wed, 12 Apr 2023 10:22:23 -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>, linux-kernel@vger.kernel.org,
        cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Juri Lelli <juri.lelli@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [RFC PATCH 0/5] cgroup/cpuset: A new "isolcpus" paritition
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Hello, Waiman.

On Wed, Apr 12, 2023 at 03:52:36PM -0400, Waiman Long wrote:
> There is still a distribution hierarchy as the list of isolation CPUs have
> to be distributed down to the target cgroup through the hierarchy. For
> example,
> 
> cgroup root
> ? +- isolcpus? (cpus 8,9; isolcpus)
> ? +- user.slice (cpus 1-9; ecpus 1-7; member)
> ???  +- user-x.slice (cpus 8,9; ecpus 8,9; isolated)
>      +- user-y.slice (cpus 1,2; ecpus 1,2; member)
> 
> OTOH, I do agree that this can be somewhat hacky. That is why I post it as a
> RFC to solicit feedback.

Wouldn't it be possible to make it hierarchical by adding another cpumask to
cpuset which lists the cpus which are allowed in the hierarchy but not used
unless claimed by an isolated domain?

Thanks.

-- 
tejun