From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Waiman Long <waiman.long@hpe.com>, Jason Low <jason.low2@hpe.com>,
Ding Tianhong <dingtianhong@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
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>
Subject: Re: [RFC][PATCH 1/3] locking/mutex: Rework mutex::owner
Date: Wed, 24 Aug 2016 17:34:12 +0200 [thread overview]
Message-ID: <20160824153412.GA10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160824095659.GC16944@arm.com>
On Wed, Aug 24, 2016 at 10:56:59AM +0100, Will Deacon wrote:
> > + owner = atomic_long_read(&lock->owner);
> > + for (;;) {
> > + unsigned long old;
> > +
> > + old = atomic_long_cmpxchg_release(&lock->owner, owner, owner & 0x03);
> > + if (old == owner)
> > + break;
> > +
> > + owner = old;
> > + }
>
> Can you rewrite this using atomic_long_fetch_and_release?
Yes, until patch 3/3.. but now that you mention it I think we can do:
owner = atomic_long_read(&lock->owner);
if (!(owner & MUTEX_FLAG_HANDOFF))
(void)atomic_long_fetch_and_release(MUTEX_FLAGS, &lock->owner);
next prev parent reply other threads:[~2016-08-24 17:15 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 12:46 [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-08-23 12:46 ` [RFC][PATCH 1/3] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-08-23 19:55 ` Waiman Long
2016-08-23 20:52 ` Tim Chen
2016-08-23 21:03 ` Peter Zijlstra
2016-08-23 21:09 ` Peter Zijlstra
2016-08-23 20:17 ` Waiman Long
2016-08-23 20:31 ` Peter Zijlstra
2016-08-24 9:56 ` Will Deacon
2016-08-24 15:34 ` Peter Zijlstra [this message]
2016-08-24 16:52 ` Peter Zijlstra
2016-08-24 16:54 ` Will Deacon
2016-08-23 12:46 ` [RFC][PATCH 2/3] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-08-23 12:46 ` [RFC][PATCH 3/3] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-08-23 12:56 ` Peter Zijlstra
[not found] ` <57BCA869.1050501@hpe.com>
2016-08-23 20:32 ` Peter Zijlstra
2016-08-24 19:50 ` Waiman Long
2016-08-25 8:11 ` Peter Zijlstra
2016-08-23 16:17 ` [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex Davidlohr Bueso
2016-08-23 16:35 ` Jason Low
2016-08-23 16:57 ` Peter Zijlstra
2016-08-23 19:36 ` Waiman Long
2016-08-23 20:41 ` Peter Zijlstra
2016-08-23 22:34 ` Waiman Long
2016-08-24 1:13 ` Jason Low
2016-08-25 12:32 ` Peter Zijlstra
2016-08-25 15:43 ` Peter Zijlstra
2016-08-25 16:33 ` Waiman Long
2016-08-25 16:35 ` Peter Zijlstra
2016-08-27 18:27 ` Ingo Molnar
2016-08-25 19:11 ` huang ying
2016-08-25 19:26 ` Peter Zijlstra
2016-08-23 18:53 ` Linus Torvalds
2016-08-23 20:34 ` Peter Zijlstra
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