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Groups > linux.kernel > #1359610
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: RFC on fixing mutex spinning on owner |
| Date | 2016-03-17 08:40 +0100 |
| Message-ID | <rdAHg-4j7-7@gated-at.bofh.it> (permalink) |
| References | <rdt34-7Be-37@gated-at.bofh.it> <rdtcK-7ER-13@gated-at.bofh.it> <rdtcK-7ER-27@gated-at.bofh.it> <rdvHA-UH-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Mar 16, 2016 at 10:17:51PM -0400, Steven Rostedt wrote:
> Actually, the preempt off section here is not really an issue:
>
> rcu_read_lock();
> while (owner_running(lock, owner)) {
> if (need_resched())
> break;
>
> cpu_relax_lowlatency();
> }
> rcu_read_unlock();
>
> Although preemption may be disabled, that "need_resched()" check will
> break out of the loop if a higher priority task were to want to run on
> this CPU.
>
> I probably should add a hook there to let the preemptoff tracer know
> that this is not an issue.
Urgh, there's a lot of such spin loops all over, that's going to be a
pain to annotate all.
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RFC on fixing mutex spinning on owner Joel Fernandes <agnel.joel@gmail.com> - 2016-03-17 00:30 +0100
Re: RFC on fixing mutex spinning on owner Greg Kroah-Hartman <greg@kroah.com> - 2016-03-17 00:40 +0100
Re: RFC on fixing mutex spinning on owner Joel Fernandes <agnel.joel@gmail.com> - 2016-03-17 00:40 +0100
Re: RFC on fixing mutex spinning on owner Steven Rostedt <rostedt@goodmis.org> - 2016-03-17 03:20 +0100
Re: RFC on fixing mutex spinning on owner Joel Fernandes <agnel.joel@gmail.com> - 2016-03-17 06:40 +0100
Re: RFC on fixing mutex spinning on owner Steven Rostedt <rostedt@goodmis.org> - 2016-03-17 13:10 +0100
Re: RFC on fixing mutex spinning on owner Peter Zijlstra <peterz@infradead.org> - 2016-03-17 08:40 +0100
Re: RFC on fixing mutex spinning on owner Nicholas Mc Guire <der.herr@hofr.at> - 2016-03-17 10:10 +0100
Re: RFC on fixing mutex spinning on owner Peter Zijlstra <peterz@infradead.org> - 2016-03-17 11:20 +0100
Re: RFC on fixing mutex spinning on owner Thomas Gleixner <tglx@linutronix.de> - 2016-03-17 12:20 +0100
Re: RFC on fixing mutex spinning on owner Steven Rostedt <rostedt@goodmis.org> - 2016-03-17 13:10 +0100
Re: RFC on fixing mutex spinning on owner Peter Zijlstra <peterz@infradead.org> - 2016-03-17 13:20 +0100
Re: RFC on fixing mutex spinning on owner Thomas Gleixner <tglx@linutronix.de> - 2016-03-17 14:40 +0100
Re: RFC on fixing mutex spinning on owner Nicholas Mc Guire <der.herr@hofr.at> - 2016-03-17 17:50 +0100
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