From: "Paul E. McKenney" <paulmck@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
rcu <rcu@vger.kernel.org>, Josh Triplett <josh@joshtriplett.org>,
rostedt <rostedt@goodmis.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
"Joel Fernandes, Google" <joel@joelfernandes.org>
Subject: Re: tasks-trace RCU: question about grace period forward progress
Date: Thu, 25 Feb 2021 15:05:31 -0800 [thread overview]
Message-ID: <20210225230531.GW2743@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20210225222318.GG4746@worktop.programming.kicks-ass.net>
On Thu, Feb 25, 2021 at 11:23:18PM +0100, Peter Zijlstra wrote:
> On Thu, Feb 25, 2021 at 10:33:21AM -0800, Paul E. McKenney wrote:
> > One question for Peter... Does each and every context switch imply a
> > full barrier?
>
> Yes, also see the smp_mb__after_spinlock() in __schedule() :-)
Whew!!! ;-)
Yeah, I could make RCU Tasks Trace deal with lack of a full barrier in
that case, but I would rather not... I could imagine optimizing so
that the full barrier happened only when tasks migrated, but I could
also imagine a world of hurt stemming from such an optimization!
Thanx, Paul
prev parent reply other threads:[~2021-02-25 23:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 14:22 Mathieu Desnoyers
2021-02-25 15:36 ` Paul E. McKenney
2021-02-25 15:47 ` Mathieu Desnoyers
2021-02-25 18:33 ` Paul E. McKenney
2021-02-25 20:20 ` Mathieu Desnoyers
2021-02-25 20:55 ` Paul E. McKenney
2021-02-25 22:23 ` Peter Zijlstra
2021-02-25 23:05 ` Paul E. McKenney [this message]
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=20210225230531.GW2743@paulmck-ThinkPad-P72 \
--to=paulmck@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=joel@joelfernandes.org \
--cc=josh@joshtriplett.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=peterz@infradead.org \
--cc=rcu@vger.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
all inboxes | Powered by JetHome®