From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Joe Korty <joe.korty@concurrent-rt.com>
Cc: Julia Cartwright <julia@ni.com>,
tglx@linutronix.de, rostedt@goodmis.org,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH RT] sched/migrate_disable: fallback to preempt_disable() instead barrier()
Date: Thu, 5 Jul 2018 18:59:37 +0200 [thread overview]
Message-ID: <20180705165937.5orx3md3krg4akaz@linutronix.de> (raw)
In-Reply-To: <20180705161807.GA5800@zipoli.concurrent-rt.com>
On 2018-07-05 12:18:07 [-0400], joe.korty@concurrent-rt.com wrote:
> Hi Sebastian,
Hi Joe,
> I just verified that this fix does not work for my mix of
> config options (smp && preempt && !rt).
Okay. So for !RT+SMP we keep migrate_disable() around and it almost
nothing. And it is not referenced anywhere so it does not matter as long
as it not used directly.
We could turn migrate_disable() into a nop/barrier but then we have
three uses which do preempt_disable() -> migrate_disable() (see other
thread).
For the futex code it should not matter much because at this point
preemption is disabled due to the spin_lock() (so we would just extend
it past the spin_unlock() or wake_futex_pi() which ends with
preempt_enable()).
> Regards,
> Joe
Sebastian
next prev parent reply other threads:[~2018-07-05 16:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-04 17:35 [PATCH RT] sample fix for splat in futex_[un]lock_pi for !rt joe.korty
2018-07-05 15:50 ` [PATCH RT] sched/migrate_disable: fallback to preempt_disable() instead barrier() Sebastian Andrzej Siewior
2018-07-05 16:18 ` joe.korty
2018-07-05 16:59 ` Sebastian Andrzej Siewior [this message]
2018-07-06 10:58 ` [PATCH RT v2] " Sebastian Andrzej Siewior
2018-07-06 19:05 ` joe.korty
2018-07-11 15:39 ` Sebastian Andrzej Siewior
2018-07-11 15:43 ` Steven Rostedt
2018-07-05 16:23 ` [PATCH RT] " Steven Rostedt
2018-07-05 16:38 ` Sebastian Andrzej Siewior
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=20180705165937.5orx3md3krg4akaz@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=joe.korty@concurrent-rt.com \
--cc=julia@ni.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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).