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Date: Wed, 27 Dec 2006 16:52:46 -0800 (PST)
Message-Id: <20061227.165246.112622837.davem@davemloft.net>
To: torvalds@osdl.org
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Subject: Re: [PATCH] mm: fix page_mkclean_one
From: David Miller <davem@davemloft.net>
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From: Linus Torvalds <torvalds@osdl.org>
Date: Wed, 27 Dec 2006 16:39:43 -0800 (PST)

> 
> 
> On Wed, 27 Dec 2006, Linus Torvalds wrote:
> > 
> > I think the test-case could probably be improved by having a munmap() and 
> > page-cache flush in between the writing and the checking, to see whether 
> > that shows the corruption easier (and possibly without having to start 
> > paging in order to throw the pages out, which would simplify testing a 
> > lot).
> 
> I think the page-writeout is implicated, because I do seem to need it, but 
> the page-cache flush does seem to make corruption _easier_ to see. I now 
> seem about to trigger it with a 100MB file on a 256MB machine in a minute 
> or so, with this slight modification.
> 
> I still don't see _why_, though. But maybe smarter people than me can see 
> it..

FWIW this program definitely triggers the bug for me.