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Date: Sat, 13 Feb 2016 10:14:18 -0800
From: Davidlohr Bueso <dave@stgolabs.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <Waiman.Long@hpe.com>, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ding Tianhong <dingtianhong@huawei.com>,
        Jason Low <jason.low2@hpe.com>,
        "Paul E. McKenney" <paulmck@us.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <Will.Deacon@arm.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Waiman Long <Waiman.Long@hp.com>
Subject: Re: [PATCH v2 1/4] locking/mutex: Add waiter parameter to
 mutex_optimistic_spin()
Message-ID: <20160213181418.GA28112@linux-uzut.site>
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On Sat, 13 Feb 2016, Peter Zijlstra wrote:

>Can't see it do that, also, if it were to do that, we'd not be here
>since having a waiter would then mean no spinners and no starvation
>etc..

I was having a hard time understanding why on earth you didn't see that. And yes
I was also wondering why it was even there... but I was looking at -next, where we
have Ding's original patch b9ce3647b4901071b0dd35d62954a4bb0e5ba1d1.... Paul, could
you drop this patch?

But yeah, I do agree that waiters should also do the mutex_can_spin_on_owner()
check unless I'm missing something subtle from Waiman.

Thanks,
Davidlohr