Re: [PATCH v3 08/14] cgroup: Remove redundant rcu_read_lock/unlock() in spin_lock
From: Tejun Heo
Date: Tue Sep 16 2025 - 14:37:26 EST
On Tue, Sep 16, 2025 at 12:47:29PM +0800, pengdonglin wrote:
> From: pengdonglin <pengdonglin@xxxxxxxxxx>
>
> Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
> there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
> rcu_read_lock_sched() in terms of RCU read section and the relevant grace
> period. That means that spin_lock(), which implies rcu_read_lock_sched(),
> also implies rcu_read_lock().
>
> There is no need no explicitly start a RCU read section if one has already
> been started implicitly by spin_lock().
>
> Simplify the code and remove the inner rcu_read_lock() invocation.
>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Waiman Long <longman@xxxxxxxxxx>
> Signed-off-by: pengdonglin <pengdonglin@xxxxxxxxxx>
> Signed-off-by: pengdonglin <dolinux.peng@xxxxxxxxx>
Applied to cgroup/for-6.18.
Thanks.
--
tejun