From: Andi Kleen <ak@suse.de>
To: Steve Bergman <sbergman@rueb.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Free memory level in 2.6.16?
Date: 05 Oct 2006 22:01:53 +0200 [thread overview]
Message-ID: <p73k63ezg3y.fsf@verdi.suse.de> (raw)
In-Reply-To: <1160034527.23009.7.camel@localhost>
Steve Bergman <sbergman@rueb.com> writes:
> Due to some problems I was having with the CentOS4.4 kernel, I just
> moved a box (x86 with 4GB ram) to 2.6.16.29 from kernel.org.
>
> All is well, but I am curious about one thing. This is a fairly memory
> hungry box, serving about 40 gnome desktops via xdmcp. All VM settings
> are at the default. Swappiness=60, min_free_kbytes=3831.
>
> However, it seems to seek out about 150MB for the level of free memory
> that it maintains. Typically I see somewhere between 100MB an 500MB in
> swap, buffers+cache is about 500MB, and 150MB is free.
>
> If I cat from /dev/md0 to /dev/null, the free memory does go down, to
> 25MB or so, but then I can watch as it seeks out about 150MB of free
> memory.
>
> To me, free memory is wasted memory. Is this a bug or a feature?
Normally it keeps some memory free for interrupt handlers which
cannot free other memory. But 150MB is indeed a lot, especially
it's only in the ~900MB lowmem zone.
You could play with /proc/sys/vm/lowmem_reserve_ratio but must
likely some defaults need tweaking.
-Andi
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next parent reply other threads:[~2006-10-05 20:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1160034527.23009.7.camel@localhost>
2006-10-05 20:01 ` Andi Kleen [this message]
2006-10-05 20:10 ` Steve Bergman
2006-10-05 20:17 ` Andi Kleen
2006-10-05 20:41 ` Steve Bergman
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