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Message-ID: <0eae9e7c-8bfc-6e89-c4ad-e1cd40ec03b5@redhat.com>
Date:   Wed, 29 Mar 2023 12:05:20 -0400
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Subject: Re: [PATCH 6/7] cgroup/cpuset: Protect DL BW data against parallel
 cpuset_attach()
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To:     Juri Lelli <juri.lelli@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Qais Yousef <qyousef@layalina.io>, Tejun Heo <tj@kernel.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Hao Luo <haoluo@google.com>
Cc:     linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        luca.abeni@santannapisa.it, claudio@evidence.eu.com,
        tommaso.cucinotta@santannapisa.it, bristot@redhat.com,
        mathieu.poirier@linaro.org,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Wei Wang <wvw@google.com>, Rick Yiu <rickyiu@google.com>,
        Quentin Perret <qperret@google.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sudeep Holla <sudeep.holla@arm.com>
References: <20230329125558.255239-1-juri.lelli@redhat.com>
 <20230329160240.2093277-1-longman@redhat.com>
From:   Waiman Long <longman@redhat.com>
In-Reply-To: <20230329160240.2093277-1-longman@redhat.com>
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On 3/29/23 12:02, Waiman Long wrote:
> It is possible to have parallel attach operations to the same cpuset in
> progress. To avoid possible corruption of single set of DL BW data in
> the cpuset structure, we have to disallow parallel attach operations if
> DL tasks are present. Attach operations can still proceed in parallel
> as long as no DL tasks are involved.
>
> This patch also stores the CPU where DL BW is allocated and free that BW
> back to the same CPU in case cpuset_can_attach() is called.
>
> Signed-off-by: Waiman Long <longman@redhat.com>

Juri, this patch is an addendum to your series to address the issues 
that I found from the cpuset point of view.

Cheers,
Longman