From: Waiman Long <waiman.long@hpe.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jason Low <jason.low2@hpe.com>, Ingo Molnar <mingo@redhat.com>,
<imre.deak@intel.com>, <linux-kernel@vger.kernel.org>,
Jason Low <jason.low2@hp.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Tim Chen <tim.c.chen@linux.intel.com>, <terry.rudd@hpe.com>,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: [PATCH v2] locking/mutex: Prevent lock starvation when spinning is enabled
Date: Thu, 18 Aug 2016 11:22:10 -0400 [thread overview]
Message-ID: <57B5D2A2.3060403@hpe.com> (raw)
In-Reply-To: <20160818141404.GA10121@twins.programming.kicks-ass.net>
On 08/18/2016 10:14 AM, Peter Zijlstra wrote:
> On Wed, Aug 10, 2016 at 11:44:08AM -0700, Jason Low wrote:
>> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
>> index 2cb7531..5643a233 100644
>> --- a/include/linux/mutex.h
>> +++ b/include/linux/mutex.h
>> @@ -57,6 +57,8 @@ struct mutex {
>> #endif
>> #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
>> struct optimistic_spin_queue osq; /* Spinner MCS lock */
>> +#elif defined(CONFIG_SMP)
>> + bool yield_to_waiter; /* Prevent starvation when spinning disabled */
>> #endif
>> #ifdef CONFIG_DEBUG_MUTEXES
>> void *magic;
> Isn't this also possible on !SMP&& PREEMPT ?
I don't think there is any realistic chance that starvation will happen
on a uniprocessor system with preemptible kernel. So I don't think that
is necessary.
Cheers,
Longman
next prev parent reply other threads:[~2016-08-19 0:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-10 18:44 [PATCH v2] locking/mutex: Prevent lock starvation when spinning is enabled Jason Low
2016-08-10 20:00 ` kbuild test robot
2016-08-10 20:01 ` kbuild test robot
2016-08-16 20:19 ` Jason Low
2016-08-10 22:07 ` Jason Low
2016-08-11 2:30 ` Jason Low
2016-08-11 15:40 ` Waiman Long
2016-08-16 19:44 ` Jason Low
2016-08-17 1:41 ` Wanpeng Li
2016-08-17 18:30 ` Jason Low
2016-08-18 0:38 ` Wanpeng Li
2016-08-18 14:14 ` Peter Zijlstra
2016-08-18 15:22 ` Waiman Long [this message]
2016-08-18 14:27 ` Peter Zijlstra
2016-08-18 15:18 ` Peter Zijlstra
2016-08-18 15:30 ` Peter Zijlstra
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