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Date: Thu, 8 Jul 2004 21:51:28 -0700
From: Andrew Morton <akpm@osdl.org>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: nickpiggin@yahoo.com.au, petero2@telia.com, linux-kernel@vger.kernel.org
Subject: Re: Can't make use of swap memory in 2.6.7-bk19
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William Lee Irwin III <wli@holomorphy.com> wrote:
>
> William Lee Irwin III <wli@holomorphy.com> wrote:
> >> Enumerate those more basic things.
> 
> On Thu, Jul 08, 2004 at 07:12:54PM -0700, Andrew Morton wrote:
> > 1: work out why it's prematurely calling out_of_memory() when laptop_mode=1.
> 
> The obvious difference in writeback policy.

The writeback code isn't in the picture with this workload - there's no
dirty pagecache around.

> I've apparently touched on policy, and paid for that mistake with an
> overpoweringly Sterculian whiff of penguins. Now backing away slowly...

Not sure what that means.

The problem is trivial to reproduce.  Killing these lines in shrink_list():

			if (laptop_mode && !sc->may_writepage)
				goto keep_locked;

makes it go away.  Something's out of whack in there, and the removal of
the free swapspace test exposed some prior problem.  I'll poke at it some
more.