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From: Shakeel Butt <shakeel.butt@linux.dev>
To: Gregory Price <gourry@gourry.net>
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org,  kernel-team@meta.com,
	longman@redhat.com, hannes@cmpxchg.org,  mhocko@kernel.org,
	roman.gushchin@linux.dev, muchun.song@linux.dev,  tj@kernel.org,
	mkoutny@suse.com, akpm@linux-foundation.org
Subject: Re: [PATCH] cpuset: relax locking on cpuset_node_allowed
Date: Mon, 21 Apr 2025 21:41:13 -0700	[thread overview]
Message-ID: <CAGj-7pXC0fDLWsuUh7PLNSyzCv-4LqKoOfE=hizUeOfoJqQ7Ag@mail.gmail.com> (raw)
In-Reply-To: <20250422043055.1932434-1-gourry@gourry.net>

On Mon, Apr 21, 2025 at 9:30 PM Gregory Price <gourry@gourry.net> wrote:
>
> The cgroup_get_e_css reference protects the css->effective_mems, and
> calls of this interface would be subject to the same race conditions
> associated with a non-atomic access to cs->effective_mems.
>
> So while this interface cannot make strong guarantees of correctness,
> it can therefore avoid taking a global or rcu_read_lock for performance.
>
> Drop the rcu_read_lock from cpuset_node_allowed.
>
> Suggested-by: Shakeel Butt <shakeel.butt@linux.dev>
> Suggested-by: Waiman Long <longman@redhat.com>
> Signed-off-by: Gregory Price <gourry@gourry.net>

Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>


  reply	other threads:[~2025-04-22  4:41 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-22  1:26 [PATCH v4 0/2] vmscan: enforce mems_effective during demotion Gregory Price
2025-04-22  1:26 ` [PATCH v4 1/2] cpuset: rename cpuset_node_allowed to cpuset_current_node_allowed Gregory Price
2025-04-22 17:37   ` Johannes Weiner
2025-04-22  1:26 ` [PATCH v4 2/2] vmscan,cgroup: apply mems_effective to reclaim Gregory Price
2025-04-22  2:02   ` Waiman Long
2025-04-22  4:07     ` Gregory Price
2025-04-22  4:30   ` [PATCH] cpuset: relax locking on cpuset_node_allowed Gregory Price
2025-04-22  4:41     ` Shakeel Butt [this message]
2025-04-22 17:46     ` Johannes Weiner
2025-04-22 19:57     ` Waiman Long
2025-04-22  4:41   ` [PATCH v4 2/2] vmscan,cgroup: apply mems_effective to reclaim Shakeel Butt
2025-04-22 17:41   ` Johannes Weiner
2025-04-24 20:22   ` [PATCH v5 0/2] vmscan: enforce mems_effective during demotion Gregory Price
2025-04-24 20:22     ` [PATCH v5 1/2] cpuset: rename cpuset_node_allowed to cpuset_current_node_allowed Gregory Price
2025-04-24 20:22     ` [PATCH v5 2/2] vmscan,cgroup: apply mems_effective to reclaim Gregory Price

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