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Message-ID: <1464036006.2479.35.camel@j-VirtualBox>
Subject: Re: [PATCH] locking/mutex: Set and clear owner using WRITE_ONCE()
From: Jason Low <jason.low2@hpe.com>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: jason.low2@hp.com, Waiman Long <waiman.long@hpe.com>,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Terry Rudd <terry.rudd@hpe.com>, Scott J Norton <scott.norton@hpe.com>
Date: Mon, 23 May 2016 13:40:06 -0700
In-Reply-To: <20160521010044.GC28231@linux-uzut.site>
References: <1463696630.2587.95.camel@j-VirtualBox>
	 <573F734C.7050708@hpe.com> <20160521010044.GC28231@linux-uzut.site>
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On Fri, 2016-05-20 at 18:00 -0700, Davidlohr Bueso wrote:
> On Fri, 20 May 2016, Waiman Long wrote:
> 
> >I think mutex-debug.h also needs similar changes for completeness.
> 
> Maybe, but given that with debug the wait_lock is unavoidable, doesn't
> this send the wrong message?

The mutex_set_owner() and mutex_clear_owner() can still get called in
the fastpath without the wait_lock for the debug case too correct? If
that's the case, then the WRITE_ONCE would still make sense to have in
the debug case.