From: Frederic Weisbecker <frederic@kernel.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
Uladzislau Rezki <urezki@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>, rcu <rcu@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 2/3] rcu: Defer RCU kthreads wakeup when CPU is dying
Date: Tue, 19 Dec 2023 16:47:20 +0100 [thread overview]
Message-ID: <ZYG7COHYyLNwxbNi@lothringen> (raw)
In-Reply-To: <b6da15c7-4729-4c7c-a88a-cc6773f9a371@paulmck-laptop>
On Tue, Dec 19, 2023 at 07:29:23AM -0800, Paul E. McKenney wrote:
> > +static void swake_up_one_online(struct swait_queue_head *wqh)
> > +{
> > + int cpu = get_cpu();
>
> This works because get_cpu() is currently preempt_disable(). If there are plans to
> make get_cpu() be some sort of read lock, we might deadlock when synchronize_rcu()
> is invoked from a CPU-hotplug notifier, correct?
>
> Might this be worth a comment somewhere at some point?
Sure, I can add that.
Thanks.
next prev parent reply other threads:[~2023-12-19 15:47 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-18 23:19 [PATCH 0/3] timers & RCU: Fix TREE03 stalls Frederic Weisbecker
2023-12-18 23:19 ` [PATCH 1/3] hrtimer: Report offline hrtimer enqueue Frederic Weisbecker
2023-12-18 23:19 ` [PATCH 2/3] rcu: Defer RCU kthreads wakeup when CPU is dying Frederic Weisbecker
2023-12-19 3:38 ` Joel Fernandes
2023-12-19 11:56 ` Frederic Weisbecker
2023-12-20 3:01 ` Joel Fernandes
2023-12-20 15:50 ` Frederic Weisbecker
2023-12-21 0:57 ` Paul E. McKenney
2023-12-19 15:29 ` Paul E. McKenney
2023-12-19 15:47 ` Frederic Weisbecker [this message]
2023-12-20 8:24 ` Z qiang
2023-12-20 15:13 ` Frederic Weisbecker
2024-08-12 9:10 ` Cheng-Jui Wang (王正睿)
2024-08-12 11:13 ` Frederic Weisbecker
2024-08-12 11:53 ` Cheng-Jui Wang (王正睿)
2023-12-18 23:19 ` [PATCH 3/3] rcu/exp: Remove full barrier upon main thread wakeup Frederic Weisbecker
2023-12-19 1:40 ` [PATCH 0/3] timers & RCU: Fix TREE03 stalls Paul E. McKenney
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