Message-Id: <200603310049.k2V0nVg26779@unix-os.sc.intel.com>
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Christoph Lameter'" <clameter@sgi.com>
Cc: "Nick Piggin" <nickpiggin@yahoo.com.au>,
       "Zoltan Menyhart" <Zoltan.Menyhart@bull.net>,
       "Boehm, Hans" <hans.boehm@hp.com>,
       "Grundler, Grant G" <grant.grundler@hp.com>, <akpm@osdl.org>,
       <linux-kernel@vger.kernel.org>, <linux-ia64@vger.kernel.org>
Subject: RE: Synchronizing Bit operations V2
Date: Thu, 30 Mar 2006 16:50:15 -0800
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Christoph Lameter wrote on Thursday, March 30, 2006 4:45 PM
> > I would make that MODE_RELEASE for clear_bit, simply to match the
> > observation that clear_bit is usually used in unlock path and have
> > potential less surprises.
> 
> clear_bit per se is defined as an atomic operation with no implications 
> for release or acquire. If it is used for release then either add the 
> appropriate barrier or use MODE_RELEASE explicitly.
> 
> It precise the uncleanness in ia64 that such semantics are attached to 
> these bit operations which may lead people to depend on those. We need to 
> either make these explicit or not depend on them.

I know, I'm saying since it doesn't make any difference from API point of
view whether it is acq, rel, or no ordering, then just make them rel as a
"preferred" Operation on ia64.

- Ken
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