From: Joel Fernandes <joel@joelfernandes.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Josh Triplett <josh@joshtriplett.org>
Subject: Re: [PATCH 03/10] rcu: Make locking explicit in do_nocb_deferred_wakeup_common()
Date: Tue, 26 May 2020 15:59:28 -0400 [thread overview]
Message-ID: <20200526195928.GC149611@google.com> (raw)
In-Reply-To: <20200513164714.22557-4-frederic@kernel.org>
On Wed, May 13, 2020 at 06:47:07PM +0200, Frederic Weisbecker wrote:
> It can either be called inline (locally or CPU hotplug locked) when
> rdp->nocb_defer_wakeup is pending or from the nocb timer. In both cases
> the rdp is offlined and we want to take the nocb lock.
s/offlined/offloaded/
thanks,
- Joel
>
> Clarify the locking rules and expectations.
>
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> Cc: Paul E. McKenney <paulmck@kernel.org>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> Cc: Joel Fernandes <joel@joelfernandes.org>
> ---
> kernel/rcu/tree_plugin.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index 1d22b16c03e0..1dd3fdd675a1 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -2142,9 +2142,9 @@ static void do_nocb_deferred_wakeup_common(struct rcu_data *rdp)
> unsigned long flags;
> int ndw;
>
> - rcu_nocb_lock_irqsave(rdp, flags);
> + raw_spin_lock_irqsave(&rdp->nocb_lock, flags);
> if (!rcu_nocb_need_deferred_wakeup(rdp)) {
> - rcu_nocb_unlock_irqrestore(rdp, flags);
> + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
> return;
> }
> ndw = READ_ONCE(rdp->nocb_defer_wakeup);
> --
> 2.25.0
>
next prev parent reply other threads:[~2020-05-26 19:59 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 16:47 [PATCH 00/10] rcu: Allow a CPU to leave and reenter NOCB state Frederic Weisbecker
2020-05-13 16:47 ` [PATCH 01/10] rcu: Directly lock rdp->nocb_lock on nocb code entrypoints Frederic Weisbecker
2020-05-20 12:29 ` Joel Fernandes
2020-05-22 17:57 ` Paul E. McKenney
2020-05-26 15:21 ` Joel Fernandes
2020-05-26 16:29 ` Paul E. McKenney
2020-05-26 20:18 ` Joel Fernandes
2020-05-26 21:09 ` Paul E. McKenney
2020-05-26 21:27 ` Joel Fernandes
2020-05-26 22:29 ` Paul E. McKenney
2020-05-27 0:45 ` Joel Fernandes
2020-05-27 0:58 ` Paul E. McKenney
2020-06-04 11:41 ` Frederic Weisbecker
2020-06-04 16:36 ` Paul E. McKenney
2020-06-08 12:57 ` Frederic Weisbecker
2020-06-09 18:02 ` Paul E. McKenney
2020-06-10 13:12 ` Frederic Weisbecker
2020-06-10 14:02 ` Paul E. McKenney
2020-06-10 22:12 ` Frederic Weisbecker
2020-06-10 23:21 ` Paul E. McKenney
2020-06-11 1:32 ` Joel Fernandes
2020-05-13 16:47 ` [PATCH 02/10] rcu: Use direct rdp->nocb_lock operations on local calls Frederic Weisbecker
2020-05-13 16:47 ` [PATCH 03/10] rcu: Make locking explicit in do_nocb_deferred_wakeup_common() Frederic Weisbecker
2020-05-26 19:54 ` Joel Fernandes
2020-05-26 19:59 ` Joel Fernandes [this message]
2020-05-13 16:47 ` [PATCH 04/10] rcu: Implement rcu_segcblist_is_offloaded() config dependent Frederic Weisbecker
2020-05-13 18:20 ` Paul E. McKenney
2020-05-13 23:03 ` Frederic Weisbecker
2020-05-14 15:47 ` Paul E. McKenney
2020-05-13 16:47 ` [PATCH 05/10] rcu: Remove useless conditional nocb unlock Frederic Weisbecker
2020-05-13 16:47 ` [PATCH 06/10] rcu: Make nocb_cb kthread parkable Frederic Weisbecker
2020-06-11 1:34 ` Joel Fernandes
2020-05-13 16:47 ` [PATCH 07/10] rcu: Temporarily assume that nohz full CPUs might not be NOCB Frederic Weisbecker
2020-05-13 18:25 ` Paul E. McKenney
2020-05-13 23:08 ` Frederic Weisbecker
2020-05-14 15:50 ` Paul E. McKenney
2020-05-14 22:49 ` Frederic Weisbecker
2020-05-13 16:47 ` [PATCH 08/10] rcu: Allow to deactivate nocb on a CPU Frederic Weisbecker
2020-05-13 18:38 ` Paul E. McKenney
2020-05-13 22:45 ` Frederic Weisbecker
2020-05-14 15:47 ` Paul E. McKenney
2020-05-14 22:30 ` Frederic Weisbecker
2020-05-14 22:47 ` Paul E. McKenney
2020-05-14 22:55 ` Frederic Weisbecker
2020-05-26 21:20 ` Joel Fernandes
2020-05-26 22:49 ` Joel Fernandes
2020-06-04 13:10 ` Frederic Weisbecker
2020-06-11 1:32 ` Joel Fernandes
2020-06-11 17:03 ` Paul E. McKenney
2020-06-04 13:14 ` Frederic Weisbecker
2020-05-13 16:47 ` [PATCH 09/10] rcu: Allow to re-offload a CPU that used to be nocb Frederic Weisbecker
2020-05-13 18:41 ` Paul E. McKenney
2020-05-13 16:47 ` [PATCH 10/10] rcu: Nocb (de)activate through sysfs Frederic Weisbecker
2020-05-13 18:42 ` Paul E. McKenney
2020-05-13 23:23 ` Frederic Weisbecker
2020-05-14 15:51 ` Paul E. McKenney
2020-05-13 18:15 ` [PATCH 00/10] rcu: Allow a CPU to leave and reenter NOCB state Paul E. McKenney
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