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From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Darren Hart <darren@dvhart.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	fredrik.markstrom@windriver.com,
	Manfred Spraul <manfred@colorfullife.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: Re: [PATCH 2/3 v2] futex: avoid double wake up in futex_wake() on -RT
Date: Thu, 16 Apr 2015 12:49:59 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.11.1504161248410.3845@nanos> (raw)
In-Reply-To: <20150416101637.GC5029@twins.programming.kicks-ass.net>

On Thu, 16 Apr 2015, Peter Zijlstra wrote:

> On Thu, Apr 16, 2015 at 11:19:41AM +0200, Thomas Gleixner wrote:
> > So any code which does not handle a spurious wakeup is broken
> > independent of the futex changes. So really nothing to worry about.
> 
> Back when we did this:
> 
>  http://lkml.iu.edu/hypermail/linux/kernel/1109.1/01941.html
>  http://lkml.iu.edu/hypermail/linux/kernel/1109.1/01943.html
> 
> Things came apart -- notably sysvsems.
> 
> And yes its true that anything not dealing with spuriuos wakups is
> borken, but there's still quite a lot of borken out there, although I
> think we fixed all the really common ones.
> 
> But if we decide we want to go do this, I'd propose we reintroduce this
> delayed wake list thing again.

Indeed. Forgot about that completely.

Thanks,

	tglx
 

  reply	other threads:[~2015-04-16 10:49 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-07 15:03 improve futex on -RT by avoiding the double wake-up Sebastian Andrzej Siewior
2015-04-07 15:03 ` [PATCH 1/3] futex: avoid double wake up in PI futex wait / wake on -RT Sebastian Andrzej Siewior
2015-04-07 18:41   ` Thomas Gleixner
2015-04-10 14:42     ` [PATCH 1/3 v2] " Sebastian Andrzej Siewior
2015-04-07 15:03 ` [PATCH 2/3] futex: avoid double wake up in futex_wake() " Sebastian Andrzej Siewior
2015-04-07 19:47   ` Thomas Gleixner
2015-04-10 16:11     ` [PATCH 2/3 v2] " Sebastian Andrzej Siewior
2015-04-13  3:02       ` Davidlohr Bueso
2015-04-16  5:09         ` Davidlohr Bueso
2015-04-16  9:19           ` Thomas Gleixner
2015-04-16 10:16             ` Peter Zijlstra
2015-04-16 10:49               ` Thomas Gleixner [this message]
2015-04-16 14:42               ` Davidlohr Bueso
2015-04-16 15:54                 ` Peter Zijlstra
2015-04-16 16:22                   ` Davidlohr Bueso
2015-04-07 15:03 ` [PATCH 3/3] ipc/mqueue: remove STATE_PENDING Sebastian Andrzej Siewior
2015-04-07 17:48   ` Manfred Spraul
2015-04-07 18:28     ` Thomas Gleixner
2015-04-10 14:37     ` [PATCH v2] " Sebastian Andrzej Siewior
2015-04-23 22:18       ` Thomas Gleixner
2015-04-28  3:24         ` Davidlohr Bueso
2015-04-28 12:37           ` Peter Zijlstra
2015-04-28 16:36             ` Davidlohr Bueso
2015-04-28 16:43               ` Peter Zijlstra
2015-04-28 16:59                 ` Davidlohr Bueso
2015-04-29 19:44                   ` Manfred Spraul
2015-04-30 18:46                     ` Davidlohr Bueso

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