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Date: Fri, 8 Nov 2013 19:07:18 -0800
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Waiman Long <Waiman.Long@hp.com>, Thomas Gleixner <tglx@linutronix.de>,
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        George Spelvin <linux@horizon.com>,
        "Aswin Chandramouleeswaran\"" <aswin@hp.com>,
        Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v5 4/4] qrwlock: Use the mcs_spinlock helper functions
 for MCS queuing
Message-ID: <20131109030718.GN18245@linux.vnet.ibm.com>
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On Fri, Nov 08, 2013 at 05:17:07PM -0800, Tim Chen wrote:
> On Fri, 2013-11-08 at 13:21 -0800, Paul E. McKenney wrote:
> > On Mon, Nov 04, 2013 at 12:17:20PM -0500, Waiman Long wrote:
> > > There is a pending patch in the rwsem patch series that adds a generic
> > > MCS locking helper functions to do MCS-style locking. This patch
> > > will enable the queue rwlock to use that generic MCS lock/unlock
> > > primitives for internal queuing. This patch should only be merged
> > > after the merging of that generic MCS locking patch.
> > > 
> > > Signed-off-by: Waiman Long <Waiman.Long@hp.com>
> > 
> > This one does might address at least some of the earlier memory-barrier
> > issues, at least assuming that the MCS lock is properly memory-barriered.
> 
> Paul, will appreciate if you can take a look the latest version
> of MCS lock with load-acquire and store-release to see if it is now
> properly memory-barriered.

Don't worry, you cannot escape.  It is on my list.  ;-)

							Thanx, Paul