From: Joel Fernandes <joelagnelf@nvidia.com>
To: Zqiang <qiang.zhang@linux.dev>
Cc: paulmck@kernel.org, frederic@kernel.org,
neeraj.upadhyay@kernel.org, boqun.feng@gmail.com,
urezki@gmail.com, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] rcu-tasks: Remove unnecessary smp_store_release() in cblist_init_generic()
Date: Wed, 25 Feb 2026 11:00:07 -0500 [thread overview]
Message-ID: <20260225160007.GA1186891@joelbox2> (raw)
In-Reply-To: <20260105011951.72850-1-qiang.zhang@linux.dev>
On Mon, Jan 05, 2026 at 09:19:51AM +0800, Zqiang wrote:
> The cblist_init_generic() is executed during the CPU early boot
> phase due to commit:30ef09635b9e ("rcu-tasks: Initialize callback
> lists at rcu_init() time"), at this time, only one boot CPU is
> online and the irq is disabled. this commit therefore use routine
> assignment replace of smp_store_release() and WRITE_ONCE() in the
> cblist_init_generic().
>
> Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Applied for 7.1 with Paul's tag. Thanks!
--
Joel Fernandes
> ---
> kernel/rcu/tasks.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
> index 76f952196a29..c736900317cd 100644
> --- a/kernel/rcu/tasks.h
> +++ b/kernel/rcu/tasks.h
> @@ -290,9 +290,9 @@ static void cblist_init_generic(struct rcu_tasks *rtp)
> shift = ilog2(rcu_task_cpu_ids / lim);
> if (((rcu_task_cpu_ids - 1) >> shift) >= lim)
> shift++;
> - WRITE_ONCE(rtp->percpu_enqueue_shift, shift);
> - WRITE_ONCE(rtp->percpu_dequeue_lim, lim);
> - smp_store_release(&rtp->percpu_enqueue_lim, lim);
> + rtp->percpu_enqueue_shift = shift;
> + rtp->percpu_dequeue_lim = lim;
> + rtp->percpu_enqueue_lim = lim;
>
> pr_info("%s: Setting shift to %d and lim to %d rcu_task_cb_adjust=%d rcu_task_cpu_ids=%d.\n",
> rtp->name, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim),
> --
> 2.48.1
>
prev parent reply other threads:[~2026-02-25 16:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 1:19 [PATCH v2] rcu-tasks: Remove unnecessary smp_store_release() in cblist_init_generic() Zqiang
2026-01-05 21:34 ` Paul E. McKenney
2026-02-25 16:00 ` Joel Fernandes [this message]
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