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Date: Wed, 16 Apr 2008 02:52:03 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Christoph Lameter <clameter@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Pekka Enberg <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org,
       Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@suse.de>,
       Andrew Morton <akpm@linux-foundation.org>,
       "Rafael J. Wysocki" <rjw@sisk.pl>, Yinghai.Lu@sun.com, apw@shadowen.org,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Joe Perches <joe@perches.com>
Subject: Re: [patch] mm: sparsemem memory_present() memory corruption fix
Message-ID: <20080416005203.GB26996@elte.hu>
References: <20080415195430.GA23015@elte.hu> <Pine.LNX.4.64.0804151255390.1785@schroedinger.engr.sgi.com> <20080415201734.GA25628@elte.hu> <4805115D.5030703@cs.helsinki.fi> <20080415204025.GA29784@elte.hu> <alpine.LFD.1.00.0804151353380.2879@woody.linux-foundation.org> <20080416000356.GA24737@elte.hu> <20080416003449.GA26633@elte.hu> <20080416004010.GA26776@elte.hu> <Pine.LNX.4.64.0804151742010.6876@schroedinger.engr.sgi.com>
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* Christoph Lameter <clameter@sgi.com> wrote:

> I wonder why this did not show up earlier in testing? Running a kernel 
> that cannot access all of memory is unusual I guess.

i guess people saw the "you are not running a PAE kernel" warning and 
went to a PAE kernel which didnt have this issue.

OTOH, quite a few testers consciously use non-PAE kernels on 4GB 
systems, so i'd not be surprised if this solved a few mystery 
regressions we have.

	Ingo