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From: Andrew Morton <akpm@linux-foundation.org>
To: Daniel Walker <dwalker@mvista.com>
Cc: linux-kernel@vger.kernel.org, Pierre Peiffer <peifferp@gmail.com>
Subject: Re: futex: priority wakeup miss ordering
Date: Thu, 8 May 2008 01:25:03 -0700	[thread overview]
Message-ID: <20080508012503.0d023cdc.akpm@linux-foundation.org> (raw)
In-Reply-To: <1210195378.17132.237.camel@localhost.localdomain>

On Wed, 07 May 2008 14:22:58 -0700 Daniel Walker <dwalker@mvista.com> wrote:

> 
> 
> from commit ec92d08292d3e9b0823eba138a4564d2d39f25c7
> 
> The wakeup ordering should be in priority order. However if the priority
> of a task is modified while it's waiting on the futex you will get an
> out of order wakeup.
> 
> If you use a priority inheriting mutex this is correct. It's because the
> rtmutex hooks into sched_setscheduler to catch any priority changes,
> then re-queues with the new priority.. But the futex doesn't have this
> hook.
> 
> Was this intentionally left out of this priority wake up patch? I
> thought I would let you know in case you had a specific reason for not
> handling this.. 
> 

Pierre is no longer @bull.net.

  reply	other threads:[~2008-05-08  8:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-07 21:22 futex: priority wakeup miss ordering Daniel Walker
2008-05-08  8:25 ` Andrew Morton [this message]
2008-05-08 10:06 ` Thomas Gleixner
2008-05-08 16:28   ` Daniel Walker

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