From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will@kernel.org>
Cc: tglx@linutronix.de, boqun.feng@gmail.com,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Waiman Long <longman@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Mike Galbraith <efault@gmx.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH 1/4] sched/wakeup: Strengthen current_save_and_set_rtlock_wait_state()
Date: Fri, 10 Sep 2021 15:17:04 +0200 [thread overview]
Message-ID: <YTta0Kkz4OeFzUvJ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210910125658.GA1454@willie-the-truck>
On Fri, Sep 10, 2021 at 01:57:26PM +0100, Will Deacon wrote:
> On Thu, Sep 09, 2021 at 04:27:46PM +0200, Peter Zijlstra wrote:
> > Moo yes, so the earlier changelog I wrote was something like:
> >
> > current_save_and_set_rtlock_wait_state();
> > for (;;) {
> > if (try_lock())
> > break;
> >
> > raw_spin_unlock_irq(&lock->wait_lock);
> > if (!cond)
> > schedule();
> > raw_spin_lock_irq(&lock->wait_lock);
> >
> > set_current_state(TASK_RTLOCK_WAIT);
> > }
> > current_restore_rtlock_saved_state();
> >
> > which is more what the code looks like before these patches, and in that
> > case the @cond load can be lifted before __state.
>
> Ah, so that makes more sense, thanks. I can't see how the try_lock() could
> be reordered though, as it's going to have to do an atomic rmw.
OK, lemme go update the Changelog and make it __flags for bigeasy :-)
next prev parent reply other threads:[~2021-09-10 13:19 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 10:59 [PATCH 0/4] locking/rwbase: Assorted fixes Peter Zijlstra
2021-09-09 10:59 ` [PATCH 1/4] sched/wakeup: Strengthen current_save_and_set_rtlock_wait_state() Peter Zijlstra
2021-09-09 13:45 ` Will Deacon
2021-09-09 14:27 ` Peter Zijlstra
2021-09-10 12:57 ` Will Deacon
2021-09-10 13:17 ` Peter Zijlstra [this message]
2021-09-10 14:01 ` Peter Zijlstra
2021-09-10 15:06 ` Will Deacon
2021-09-10 16:07 ` Waiman Long
2021-09-10 17:09 ` Peter Zijlstra
2021-09-12 3:57 ` Boqun Feng
2021-09-10 12:45 ` Sebastian Andrzej Siewior
2021-09-13 22:08 ` Thomas Gleixner
2021-09-13 22:52 ` Thomas Gleixner
2021-09-14 6:45 ` Peter Zijlstra
2021-09-09 10:59 ` [PATCH 2/4] locking/rwbase: Properly match set_and_save_state() to restore_state() Peter Zijlstra
2021-09-09 13:53 ` Will Deacon
2021-09-14 7:31 ` Thomas Gleixner
2021-09-16 11:59 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-09-09 10:59 ` [PATCH 3/4] locking/rwbase: Fix rwbase_write_lock() vs __rwbase_read_lock() Peter Zijlstra
2021-09-14 7:45 ` Thomas Gleixner
2021-09-14 13:59 ` Peter Zijlstra
2021-09-14 15:00 ` Thomas Gleixner
2021-09-16 11:59 ` [tip: locking/urgent] locking/rwbase: Extract __rwbase_write_trylock() tip-bot2 for Peter Zijlstra
2021-09-09 10:59 ` [PATCH 4/4] locking/rwbase: Take care of ordering guarantee for fastpath reader Peter Zijlstra
2021-09-14 7:46 ` Thomas Gleixner
2021-09-16 11:59 ` [tip: locking/urgent] " tip-bot2 for Boqun Feng
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=YTta0Kkz4OeFzUvJ@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bigeasy@linutronix.de \
--cc=boqun.feng@gmail.com \
--cc=bristot@redhat.com \
--cc=dave@stgolabs.net \
--cc=efault@gmx.de \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mingo@kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.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®