linux-kernel - Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

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Message-ID: <20070307150102.GH18704@wotan.suse.de>
Date:	Wed, 7 Mar 2007 16:01:02 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Miklos Szeredi <miklos@...redi.hu>, akpm@...ux-foundation.org,
	mingo@...e.hu, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	benh@...nel.crashing.org, Jeff Dike <jdike@...toit.com>
Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

On Wed, Mar 07, 2007 at 03:34:27PM +0100, Peter Zijlstra wrote:
> On Wed, 2007-03-07 at 14:52 +0100, Peter Zijlstra wrote:
> 
> > True. We could even guesstimate the nonlinear dirty pages by subtracting
> > the result of page_mkclean() from page_mapcount() and force an
> > msync(MS_ASYNC) on said mapping (or all (nonlinear) mappings of the
> > related file) when some threshold gets exceeded.
> 
> Almost, but not quite, we'd need to extract another value from the
> page_mkclean() run, the actual number of mappings encountered. The
> return value only sums the number of dirty mappings encountered.
> 
> s390 would already work I guess.
> 
> Certainly doable.

But if we restrict it to root only, and have a note in the man page
about it, then it really isn't worth cluttering up the kernel.

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