From: Chris Wilson <chris@chris-wilson.co.uk>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Waiman Long <Waiman.Long@hpe.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] locking/mutex: Clear mutex-handoff flag on interrupt
Date: Wed, 11 Jan 2017 16:57:32 +0000 [thread overview]
Message-ID: <20170111165731.GB16278@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <20170111164302.GA3051@twins.programming.kicks-ass.net>
On Wed, Jan 11, 2017 at 05:43:02PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 09, 2017 at 11:52:03AM +0000, Chris Wilson wrote:
> > If we abort the mutex_lock() due to an interrupt, or other error from
>
> s/interrupt/signal/, right?
Yes. EINTR is ingrained.
> > ww_mutex, we need to relinquish the handoff flag if we applied it.
> > Otherwise, we may cause missed wakeups as the current owner may try to
> > handoff to a new thread that is not expecting the handoff and so sleep
> > thinking the lock is already claimed (and since the owner unlocked there
> > may never be a new wakeup).
>
> Isn't that the exact same scenario as Nicolai fixed here:
>
> http://lkml.kernel.org/r/1482346000-9927-3-git-send-email-nhaehnle@gmail.com
>
> Did you, like Nicolai, find this by inspection, or can you reproduce?
Looks like it should be. It takes about 20 minutes of running a stress
test, but it is very reliably hit on the current kernel.
> FWIW, I have the below patch that should also solve this problem afaict.
Thanks, I shall see if makes my machines happy.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
next prev parent reply other threads:[~2017-01-11 16:58 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 14:52 [PATCH -v4 0/8] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 1/8] locking/drm: Kill mutex trickery Peter Zijlstra
2016-10-07 15:43 ` Peter Zijlstra
2016-10-07 15:58 ` Linus Torvalds
2016-10-07 16:13 ` Peter Zijlstra
2016-10-07 21:58 ` Waiman Long
2016-10-08 11:58 ` Thomas Gleixner
2016-10-08 14:01 ` Peter Zijlstra
2016-10-08 14:11 ` Thomas Gleixner
2016-10-08 16:42 ` Peter Zijlstra
2016-11-09 10:38 ` Peter Zijlstra
2016-10-18 12:48 ` Peter Zijlstra
2016-10-18 12:57 ` Peter Zijlstra
2016-11-11 11:22 ` Daniel Vetter
2016-11-11 11:38 ` Peter Zijlstra
2016-11-12 10:58 ` Ingo Molnar
2016-11-14 14:04 ` Peter Zijlstra
2016-11-14 14:27 ` Ingo Molnar
2016-10-18 12:57 ` Chris Wilson
2016-10-07 14:52 ` [PATCH -v4 2/8] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-10-12 17:59 ` Davidlohr Bueso
2016-10-12 19:52 ` Jason Low
2016-10-13 15:18 ` Will Deacon
2016-10-07 14:52 ` [PATCH -v4 3/8] locking/mutex: Kill arch specific code Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 4/8] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 5/8] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-10-13 15:14 ` Will Deacon
2016-10-17 9:22 ` Peter Zijlstra
2016-10-17 18:45 ` Waiman Long
2016-10-17 19:07 ` Waiman Long
2016-10-18 13:02 ` Peter Zijlstra
2016-10-18 12:36 ` Peter Zijlstra
2016-12-27 13:55 ` Chris Wilson
2017-01-09 11:52 ` [PATCH] locking/mutex: Clear mutex-handoff flag on interrupt Chris Wilson
2017-01-11 16:43 ` Peter Zijlstra
2017-01-11 16:57 ` Chris Wilson [this message]
2017-01-12 20:58 ` Chris Wilson
2016-10-07 14:52 ` [PATCH -v4 6/8] locking/mutex: Restructure wait loop Peter Zijlstra
2016-10-13 15:17 ` Will Deacon
2016-10-17 10:44 ` Peter Zijlstra
2016-10-17 13:24 ` Peter Zijlstra
2016-10-17 13:45 ` Boqun Feng
2016-10-17 15:49 ` Peter Zijlstra
2016-10-19 17:34 ` Peter Zijlstra
2016-10-24 1:57 ` ciao set_task_state() (was Re: [PATCH -v4 6/8] locking/mutex: Restructure wait loop) Davidlohr Bueso
2016-10-24 13:26 ` Kent Overstreet
2016-10-24 14:27 ` Kent Overstreet
2016-10-25 16:55 ` Eric Wheeler
2016-10-25 17:45 ` Kent Overstreet
2016-10-17 23:16 ` [PATCH -v4 6/8] locking/mutex: Restructure wait loop Waiman Long
2016-10-18 13:14 ` Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 7/8] locking/mutex: Simplify some ww_mutex code in __mutex_lock_common() Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 8/8] locking/mutex: Enable optimistic spinning of woken waiter Peter Zijlstra
2016-10-13 15:28 ` Will Deacon
2016-10-17 9:32 ` Peter Zijlstra
2016-10-17 23:21 ` Waiman Long
2016-10-18 12:19 ` Peter Zijlstra
2016-10-07 15:20 ` [PATCH -v4 0/8] locking/mutex: Rewrite basic mutex Linus Torvalds
2016-10-11 18:42 ` Jason Low
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