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Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes
	nonlinear)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Miklos Szeredi <miklos@szeredi.hu>, mingo@elte.hu, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org, benh@kernel.crashing.org
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Date: Wed, 07 Mar 2007 11:06:42 +0100
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On Wed, 2007-03-07 at 11:04 +0100, Nick Piggin wrote:
> On Wed, Mar 07, 2007 at 10:45:03AM +0100, Nick Piggin wrote:
> > On Wed, Mar 07, 2007 at 10:32:22AM +0100, Peter Zijlstra wrote:
> > > 
> > > Can recollect as much, I modelled it after page_referenced() and can't
> > > find any VM_NONLINEAR specific code in there either.
> > > 
> > > Will have a hard look, but if its broken, then page_referenced if
> > > equally broken it seems, which would make page reclaim funny in the
> > > light of nonlinear mappings.
> > 
> > page_referenced is just an heuristic, and it ignores nonlinear mappings
> > and the page which will get filtered down to try_to_unmap.
> > 
> > Page reclaim is already "funny" for nonlinear mappings, page_referenced
> > is the least of its worries ;) It works, though.
> 
> Or, to be more helpful, unmap_mapping_range is what it should be
> modelled on.

*sigh* yes was looking at all that code, thats gonna be darn slow
though, but I'll whip up a patch.

/me feels terribly bad about having missed this..