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 06/10] rcu: Make nocb_cb kthread parkable
Date: Wed, 10 Jun 2020 21:34:26 -0400 [thread overview]
Message-ID: <20200611013426.GB12037@google.com> (raw)
In-Reply-To: <20200513164714.22557-7-frederic@kernel.org>
On Wed, May 13, 2020 at 06:47:10PM +0200, Frederic Weisbecker wrote:
> This will be necessary to correctly implement rdp de-offloading. We
> don't want rcu_do_batch() in nocb_cb kthread to race with local
> rcu_do_batch().
>
> 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>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
thanks,
- Joel
> ---
> kernel/rcu/tree_plugin.h | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index 1dd3fdd675a1..43ecc047af26 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -2104,7 +2104,9 @@ static void nocb_cb_wait(struct rcu_data *rdp)
> if (needwake_gp)
> rcu_gp_kthread_wake();
> swait_event_interruptible_exclusive(rdp->nocb_cb_wq,
> - !READ_ONCE(rdp->nocb_cb_sleep));
> + !READ_ONCE(rdp->nocb_cb_sleep) ||
> + kthread_should_park());
> +
> if (!smp_load_acquire(&rdp->nocb_cb_sleep)) { /* VVV */
> /* ^^^ Ensure CB invocation follows _sleep test. */
> return;
> @@ -2125,6 +2127,8 @@ static int rcu_nocb_cb_kthread(void *arg)
> // if there are no more ready callbacks, waits for them.
> for (;;) {
> nocb_cb_wait(rdp);
> + if (kthread_should_park())
> + kthread_parkme();
> cond_resched_tasks_rcu_qs();
> }
> return 0;
> --
> 2.25.0
>
next prev parent reply other threads:[~2020-06-11 1:34 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200611013426.GB12037@google.com \
--to=joel@joelfernandes.org \
--cc=frederic@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=josh@joshtriplett.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=paulmck@kernel.org \
--cc=rostedt@goodmis.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).