From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v9 4/5] qrwlock: Use smp_store_release() in write_unlock()
Date: Tue, 21 Jan 2014 16:49:54 +0100
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To: Waiman Long <waiman.long@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>, Andrew Morton <akpm@linux-foundation.org>, Michel Lespinasse <walken@google.com>, Andi Kleen <andi@firstfloor.org>, Rik van Riel <riel@redhat.com>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Linus Torvalds <torvalds@linux-foundation.org>, Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>, George Spelvin <linux@horizon.com>, Tim Chen <tim.c.chen@linux.intel.com>, aswin@hp.com, Scott J Norton <scott.norton@hp.com>
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On Tue, Jan 21, 2014 at 10:45:42AM -0500, Waiman Long wrote:
> I can change the logic to use only cmpxchg for readers, but I don't see a
> compelling reason to do so.

The fact that you can then use smp_store_release() is fairly compelling
methinks.