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To: William Lee Irwin III <wli@holomorphy.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Andrew Morton <akpm@osdl.org>,
       linux-kernel@vger.kernel.org
Subject: Re: Can't make use of swap memory in 2.6.7-bk19
References: <m2brir9t6d.fsf@telia.com> <40ECADF8.7010207@yahoo.com.au>
	<m2fz82hq8c.fsf@telia.com> <20040708012005.6232a781.akpm@osdl.org>
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From: Peter Osterlund <petero2@telia.com>
Date: 14 Jul 2004 22:00:03 +0200
In-Reply-To: <20040714132256.GR3411@holomorphy.com>
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William Lee Irwin III <wli@holomorphy.com> writes:

> The only difference laptop_mode should have is dirty memory handling,
> but you don't have any dirty memory. Maybe swapcache is fooling things.
> Most notably, add_to_swap() sets the page dirty...
> 
> Something is very wrong here... could you try this?
...
> Index: oom-2.6.8-rc1/mm/vmscan.c
> ===================================================================
> --- oom-2.6.8-rc1.orig/mm/vmscan.c	2004-07-14 06:17:13.876343912 -0700
> +++ oom-2.6.8-rc1/mm/vmscan.c	2004-07-14 06:22:15.986416200 -0700
> @@ -417,7 +417,8 @@
>  				goto keep_locked;
>  			if (!may_enter_fs)
>  				goto keep_locked;
> -			if (laptop_mode && !sc->may_writepage)
> +			if (laptop_mode && !sc->may_writepage &&
> +							!PageSwapCache(page))
>  				goto keep_locked;
>  
>  			/* Page is dirty, try to write it out here */

This patch fixes my problem. No more bogus OOMs in laptop mode, and
the test program runs approximately equally fast in laptop mode as it
does in "normal" mode.

Thanks.

-- 
Peter Osterlund - petero2@telia.com
http://w1.894.telia.com/~u89404340