From: Waiman Long <waiman.long@hpe.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jason Low <jason.low2@hpe.com>,
"Ding Tianhong" <dingtianhong@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <Will.Deacon@arm.com>, Ingo Molnar <mingo@redhat.com>,
Imre Deak <imre.deak@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Tim Chen <tim.c.chen@linux.intel.com>,
Terry Rudd <terry.rudd@hpe.com>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Jason Low <jason.low2@hp.com>,
Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [RFC][PATCH -v2 1/4] locking/drm/i915: Kill mutex trickery
Date: Thu, 25 Aug 2016 15:59:42 -0400 [thread overview]
Message-ID: <57BF4E2E.2020406@hpe.com> (raw)
In-Reply-To: <CAKMK7uH4ngLFB+r3at_Emb_Dr_DQ22-yvSM-U2e8Q+0AFd4_Qg@mail.gmail.com>
On 08/25/2016 03:36 PM, Daniel Vetter wrote:
> On Thu, Aug 25, 2016 at 8:37 PM, Peter Zijlstra<peterz@infradead.org> wrote:
>> Poking at lock internals is not cool. Since I'm going to change the
>> implementation this will break, take it out.
>>
>> Cc: Chris Wilson<chris@chris-wilson.co.uk>
>> Cc: Daniel Vetter<daniel.vetter@ffwll.ch>
>> Signed-off-by: Peter Zijlstra (Intel)<peterz@infradead.org>
> It's horrible, but we die without this in spurious oom. And we haven't
> made much progress in recent years to throw out the locking scheme and
> replace it by something else that doesn't need a recursive mutex.
>
> But initerim I guess we could set our own owner field and check that
> to keep the duct-tape from getting off completely.
> -Daniel
Another alternative is to provide a standard mutex API that returns the
owner of the lock if there is a real need for this capability. Peeking
into lock internal is not a good practice.
Cheers,
Longman
next prev parent reply other threads:[~2016-08-25 20:17 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-25 18:37 [RFC][PATCH -v2 0/4] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 1/4] locking/drm/i915: Kill mutex trickery Peter Zijlstra
2016-08-25 19:36 ` Daniel Vetter
2016-08-25 19:59 ` Waiman Long [this message]
2016-08-25 18:37 ` [RFC][PATCH -v2 2/4] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 3/4] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 4/4] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-08-25 22:00 ` Waiman Long
2016-08-25 22:23 ` Peter Zijlstra
2016-08-26 14:30 ` Waiman Long
2016-08-26 15:18 ` Peter Zijlstra
2016-08-26 23:40 ` Waiman Long
2016-08-29 15:41 ` Peter Zijlstra
2016-08-30 11:53 ` Peter Zijlstra
2016-08-30 22:32 ` Waiman Long
-- strict thread matches above, loose matches on Subject: below --
2016-08-26 3:25 [RFC][PATCH -v2 1/4] locking/drm/i915: Kill mutex trickery Andreas Mohr
2016-08-26 9:10 ` Peter Zijlstra
2016-08-26 14:33 ` Waiman Long
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