From: "Paul E. McKenney" <paulmck@kernel.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org
Subject: Re: [PATCH tip/core/rcu 1/3] rcu: Provide polling interfaces for Tree RCU grace periods
Date: Mon, 15 Mar 2021 16:11:39 -0700 [thread overview]
Message-ID: <20210315231139.GQ2696@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20210312122647.GC3646@lothringen>
On Fri, Mar 12, 2021 at 01:26:47PM +0100, Frederic Weisbecker wrote:
> On Wed, Mar 03, 2021 at 04:26:30PM -0800, paulmck@kernel.org wrote:
> > /**
> > + * start_poll_state_synchronize_rcu - Snapshot and start RCU grace period
> > + *
> > + * Returns a cookie that is used by a later call to cond_synchronize_rcu()
> > + * or poll_state_synchronize_rcu() to determine whether or not a full
> > + * grace period has elapsed in the meantime. If the needed grace period
> > + * is not already slated to start, notifies RCU core of the need for that
> > + * grace period.
> > + *
> > + * Interrupts must be enabled for the case where it is necessary to awaken
> > + * the grace-period kthread.
> > + */
> > +unsigned long start_poll_synchronize_rcu(void)
> > +{
> > + unsigned long flags;
> > + unsigned long gp_seq = get_state_synchronize_rcu();
>
> Ah! It's using rcu_seq_snap() and not rcu_seq_current() and therefore it's
> waiting for a safe future grace period, right?
Exactly! ;-)
Thanx, Paul
> If so, please discard my previous email.
>
> Thanks.
next prev parent reply other threads:[~2021-03-15 23:12 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 0:26 [PATCH tip/core/rcu 0/3] Polling RCU grace-period interfaces for v5.13 Paul E. McKenney
2021-03-04 0:26 ` [PATCH tip/core/rcu 1/3] rcu: Provide polling interfaces for Tree RCU grace periods paulmck
2021-03-12 12:21 ` Frederic Weisbecker
2021-03-12 12:26 ` Frederic Weisbecker
2021-03-15 23:11 ` Paul E. McKenney [this message]
2021-03-16 14:47 ` Frederic Weisbecker
2021-03-16 16:42 ` Paul E. McKenney
2021-03-16 15:17 ` Frederic Weisbecker
2021-03-16 16:51 ` Paul E. McKenney
2021-03-18 14:59 ` Frederic Weisbecker
2021-03-18 17:09 ` Paul E. McKenney
2021-03-19 13:58 ` Frederic Weisbecker
2021-03-19 17:51 ` Paul E. McKenney
2021-03-19 22:10 ` Frederic Weisbecker
2021-03-19 23:38 ` Paul E. McKenney
2021-03-19 23:47 ` Frederic Weisbecker
2021-03-04 0:26 ` [PATCH tip/core/rcu 2/3] rcu: Provide polling interfaces for Tiny " paulmck
2021-03-21 22:28 ` Frederic Weisbecker
2021-03-22 15:47 ` Paul E. McKenney
2021-03-22 19:00 ` Frederic Weisbecker
2021-03-22 19:45 ` Paul E. McKenney
2021-03-23 14:02 ` Frederic Weisbecker
2021-03-23 16:45 ` Paul E. McKenney
2021-03-04 0:26 ` [PATCH tip/core/rcu 3/3] rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu() paulmck
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