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Date: Thu, 15 May 2008 10:28:00 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
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To: Andy Whitcroft <apw@shadowen.org>
cc: linux-mm@kvack.org, Andrew Morton <akpm@osdl.org>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Rik van Riel <riel@redhat.com>, Jeremy Fitzhardinge <jeremy@goop.org>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] page-flags: record page flag overlays explicitly
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On Thu, 15 May 2008, Andy Whitcroft wrote:

> Now that we have a single enum to generate the bit orders it makes sense
> to express overlays in the same place.  So create per use aliases for
> this bit in the main page-flags enum and use those in the accessors.

Well I thought it would be better to have the overlays defined when the 
PAGEFLAGS_xx macro is used. If that is done then every PG_xxx has a unique 
id. The aliasing is then only through PageXXXX() using a PG_yyy