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From: Jens Axboe <axboe@kernel.dk>
To: David Howells <dhowells@redhat.com>
Cc: Imre Deak <imre.deak@intel.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Dave Jones <davej@redhat.com>,
	Lukas Czerner <lczerner@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] wait: fix false timeouts when using wait_event_timeout()
Date: Thu, 2 May 2013 14:35:17 +0200	[thread overview]
Message-ID: <20130502123517.GL7800@kernel.dk> (raw)
In-Reply-To: <3633.1367497784@warthog.procyon.org.uk>

On Thu, May 02 2013, David Howells wrote:
> Imre Deak <imre.deak@intel.com> wrote:
> 
> > Many callers of the wait_event_timeout() and
> > wait_event_interruptible_timeout() expect that the return value will be
> > positive if the specified condition becomes true before the timeout
> > elapses. However, at the moment this isn't guaranteed. If the wake-up
> > handler is delayed enough, the time remaining until timeout will be
> > calculated as 0 - and passed back as a return value - even if the
> > condition became true before the timeout has passed.
> > 
> > Fix this by returning at least 1 if the condition becomes true. This
> > semantic is in line with what wait_for_condition_timeout() does; see
> > commit bb10ed09 - "sched: fix wait_for_completion_timeout() spurious
> > failure under heavy load".
> > 
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> 
> Acked-by: David Howells <dhowells@redhat.com>

You can add mine, too:

Acked-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe


  reply	other threads:[~2013-05-02 12:35 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-02  8:58 [PATCH] wait: fix false timeouts when using wait_event_timeout() Imre Deak
2013-05-02  9:36 ` Daniel Vetter
2013-05-07 23:12   ` Andrew Morton
2013-05-08  9:49     ` Imre Deak
2013-05-02 10:29 ` David Howells
2013-05-02 12:02   ` Imre Deak
2013-05-02 12:13   ` Daniel Vetter
2013-05-02 12:23     ` Jens Axboe
2013-05-02 12:29       ` David Howells
2013-05-02 12:34       ` Imre Deak
2013-05-02 12:54         ` Jens Axboe
2013-05-02 13:56           ` Imre Deak
2013-05-02 14:04             ` Daniel Vetter
2013-05-02 12:29 ` David Howells
2013-05-02 12:35   ` Jens Axboe [this message]
2013-05-02 19:56     ` Imre Deak
  -- strict thread matches above, loose matches on Subject: below --
2013-06-04 19:28 Oleg Nesterov
2013-06-04 21:35 ` Imre Deak
2013-06-04 21:40   ` Imre Deak
2013-06-05 16:37     ` Oleg Nesterov
2013-06-05 19:07       ` Oleg Nesterov
2013-06-06  1:45         ` Tejun Heo
2013-06-06 18:47           ` Oleg Nesterov

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