From: Frederic Weisbecker <frederic@kernel.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org,
Lai Jiangshan <jiangshanlai@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Neeraj Upadhyay <neeraj.iitr10@gmail.com>,
rcu@vger.kernel.org
Subject: Re: [PATCH v2] srcu: Improve comments about acceleration leak
Date: Mon, 18 Dec 2023 22:28:40 +0100 [thread overview]
Message-ID: <ZYC5iAds0sJuDYzd@localhost.localdomain> (raw)
In-Reply-To: <CAEXW_YS-p9G=fLO+-vYx9RQS9oovHbVs48aPDfGcQrNWUdXwWA@mail.gmail.com>
Le Mon, Dec 18, 2023 at 10:27:56AM -0500, Joel Fernandes a écrit :
> On Mon, Dec 18, 2023 at 7:13 AM Frederic Weisbecker <frederic@kernel.org> wrote:
> >
> > Le Sun, Dec 17, 2023 at 09:00:15PM -0500, Joel Fernandes a écrit :
> > > "Acceleration can never fail because the state of gp_seq value used
> > > for acceleration is <= the state of gp_seq used for advancing."
> > >
> > > Does that sound correct now?
> >
> > That can be confusing since acceleration relies on rcu_seq_snap() while
> > advance relies on rcu_seq_current(). And rcu_seq_snap() returns a snapshot
> > that may be above the subsequent rcu_seq_current() return value.
> >
> > So it should rather be something like:
> >
> > "The base current gp_seq value used to produce the snapshot has to
> > be <= the gp_seq used for advancing."
>
> Yeah "base current gp_seq" though probably equally confusing sounds a
> bit better, so I'll just use that instead of "state of gp_seq".
>
> With that can I add your Review tag?
Sure, sounds good!
Thanks.
>
> - Joel
>
prev parent reply other threads:[~2023-12-18 21:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-11 1:57 [PATCH v2] srcu: Improve comments about acceleration leak Joel Fernandes (Google)
2023-12-12 20:11 ` Joel Fernandes
2023-12-13 18:10 ` Paul E. McKenney
2023-12-16 21:17 ` Frederic Weisbecker
2023-12-18 2:00 ` Joel Fernandes
2023-12-18 12:13 ` Frederic Weisbecker
2023-12-18 15:27 ` Joel Fernandes
2023-12-18 21:28 ` Frederic Weisbecker [this message]
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