From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: "Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
"Xi Wang" <xii@google.com>,
"Frederic Weisbecker" <frederic@kernel.org>
Subject: Re: [PATCH v2] cgroup/cpuset: Extend kthread_is_per_cpu() check to all PF_NO_SETAFFINITY tasks
Date: Fri, 9 May 2025 07:35:44 -1000 [thread overview]
Message-ID: <aB488PJUSYng6ZDQ@slm.duckdns.org> (raw)
In-Reply-To: <20250508192413.615512-1-longman@redhat.com>
On Thu, May 08, 2025 at 03:24:13PM -0400, Waiman Long wrote:
> Commit ec5fbdfb99d1 ("cgroup/cpuset: Enable update_tasks_cpumask()
> on top_cpuset") enabled us to pull CPUs dedicated to child partitions
> from tasks in top_cpuset by ignoring per cpu kthreads. However, there
> can be other kthreads that are not per cpu but have PF_NO_SETAFFINITY
> flag set to indicate that we shouldn't mess with their CPU affinity.
> For other kthreads, their affinity will be changed to skip CPUs dedicated
> to child partitions whether it is an isolating or a scheduling one.
>
> As all the per cpu kthreads have PF_NO_SETAFFINITY set, the
> PF_NO_SETAFFINITY tasks are essentially a superset of per cpu kthreads.
> Fix this issue by dropping the kthread_is_per_cpu() check and checking
> the PF_NO_SETAFFINITY flag instead.
>
> Fixes: ec5fbdfb99d1 ("cgroup/cpuset: Enable update_tasks_cpumask() on top_cpuset")
> Signed-off-by: Waiman Long <longman@redhat.com>
Applied to cgroup/for-6.15-fixes.
Thanks.
--
tejun
prev parent reply other threads:[~2025-05-09 17:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-08 19:24 [PATCH v2] cgroup/cpuset: Extend kthread_is_per_cpu() check to all PF_NO_SETAFFINITY tasks Waiman Long
2025-05-09 13:18 ` Frederic Weisbecker
2025-05-09 14:08 ` Waiman Long
2025-05-09 17:30 ` Tejun Heo
2025-05-09 21:19 ` Frederic Weisbecker
2025-05-09 17:35 ` Tejun Heo [this message]
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