From: Tejun Heo <tj@kernel.org>
To: Waiman Long <llong@redhat.com>
Cc: Chen Ridong <chenridong@huaweicloud.com>,
hannes@cmpxchg.org, mkoutny@suse.com, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] cgroup/cpuset: remove kernfs active break
Date: Wed, 8 Jan 2025 10:00:23 -1000 [thread overview]
Message-ID: <Z37ZVyx_PI6cHwZ7@slm.duckdns.org> (raw)
In-Reply-To: <625d03cd-302f-41b1-9502-dfd25eb677e1@redhat.com>
Hello,
On Wed, Jan 08, 2025 at 02:50:19PM -0500, Waiman Long wrote:
...
> It is not the strict ordering that I am worrying about. It is all about the
> possibility of hitting some race conditions.
>
> I am thinking of a scenario where a cpuset loses all its CPUs in hotunplug
> and then restored by adding other CPUs. There is chance that the css will be
> operated on concurrently by the auto-transfer task and another task moving
> new task to the css. I am not sure if that will be a problem or not. Anyway,
> it is very rare that we will be in such a situation.
Hmm... I might be missing something but cgroup_transfer_tasks() is fully
synchronized against migrations. I don't see anything dangerous there.
Thanks.
--
tejun
next prev parent reply other threads:[~2025-01-08 20:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-06 8:19 [PATCH v2] cgroup/cpuset: remove kernfs active break Chen Ridong
2025-01-08 16:53 ` Tejun Heo
2025-01-08 19:27 ` Waiman Long
2025-01-08 19:35 ` Tejun Heo
2025-01-08 19:50 ` Waiman Long
2025-01-08 20:00 ` Tejun Heo [this message]
2025-01-08 20:04 ` Waiman Long
2025-01-08 19:20 ` Waiman Long
2025-01-08 19:23 ` Tejun Heo
2025-01-09 1:29 ` Chen Ridong
2025-01-09 1:55 ` Tejun Heo
2025-01-09 2:07 ` Chen Ridong
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