Problems with VM

Problems with VM

[ccroswhite]

I am having difficulties with memory allocation in  teh 2.4.17 kernel.
Memory is being agressively given as cache but not retrieved to be used
as 'normal' ran.  Consequently, I will have a machine that has 5M
'normal' RAM, 800M 'cache' RAM and the reset coming out of swap space.
I need this 'cache' RAM placed back into the available RAM pool to be
used by applications.  Is there a patch/kernel configuration that I can
change this behavior?

Chris Croswhite
Get2Chip, Inc.

Re: Problems with VM

[Rik van Riel]

On Thu, 14 Feb 2002 ccroswhite@get2chip.com wrote:

> I am having difficulties with memory allocation in  teh 2.4.17 kernel.
> Memory is being agressively given as cache but not retrieved to be used
> as 'normal' ran.  Consequently, I will have a machine that has 5M
> 'normal' RAM, 800M 'cache' RAM and the reset coming out of swap space.
> I need this 'cache' RAM placed back into the available RAM pool to be
> used by applications.  Is there a patch/kernel configuration that I can
> change this behavior?

If you feel adventurous, you could try my reverse mapping VM:

http://surriel.com/patches/2.4/2.4.17-rmap-12f


The changelog can be found at http://surriel.com/patches/Changelog.rmap

kind regards,

Rik
-- 
"Linux holds advantages over the single-vendor commercial OS"
    -- Microsoft's "Competing with Linux" document

http://www.surriel.com/		http://distro.conectiva.com/

Re: Problems with VM

[David Lang]

the linux kernel does not free any memory until someone needs it.

the way things should be happening is that the kernel will keep ~4-5M ram
free to be allocated instantly, and the rest of it will be used as cache.
Some percentage of the cache has been cleaned and is available to be
thrown out quickly if it is needed.

Some Swap space will be used in normal operation (when you start some
programs they use a huge amount of space and force things into swap, the
kernel will leave it there unless it is needed to run)

seeing swap space used is not cause for concern, only worry if you see
bunch of swap activity (lots of disk access) during your normal
operations.

David Lang




On Thu, 14 Feb 2002 ccroswhite@get2chip.com wrote:

> Date: Thu, 14 Feb 2002 16:18:08 -0800
> From: ccroswhite@get2chip.com
> To: linux-kernel@vger.kernel.org
> Subject: Problems with VM
>
> I am having difficulties with memory allocation in  teh 2.4.17 kernel.
> Memory is being agressively given as cache but not retrieved to be used
> as 'normal' ran.  Consequently, I will have a machine that has 5M
> 'normal' RAM, 800M 'cache' RAM and the reset coming out of swap space.
> I need this 'cache' RAM placed back into the available RAM pool to be
> used by applications.  Is there a patch/kernel configuration that I can
> change this behavior?
>
> Chris Croswhite
> Get2Chip, Inc.
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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>

Re: Problems with VM

[Alan Cox]

> as 'normal' ran.  Consequently, I will have a machine that has 5M
> 'normal' RAM, 800M 'cache' RAM and the reset coming out of swap space.
> I need this 'cache' RAM placed back into the available RAM pool to be
> used by applications.  Is there a patch/kernel configuration that I can
> change this behavior?

2.4.18-rc1 should fix the worst of that. The rmap patches in 2.4.18-ac
definitely fix it

Re: Problems with VM

[J.A. Magallon]

On 20020215 Alan Cox wrote:
>> as 'normal' ran.  Consequently, I will have a machine that has 5M
>> 'normal' RAM, 800M 'cache' RAM and the reset coming out of swap space.
>> I need this 'cache' RAM placed back into the available RAM pool to be
>> used by applications.  Is there a patch/kernel configuration that I can
>> change this behavior?
>
>2.4.18-rc1 should fix the worst of that. The rmap patches in 2.4.18-ac
>definitely fix it
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/
>

Or oyu can try the next patch from Andrea Arcangeli for the vm, still
to include in mainline. I have adapted it to apply cleanly on plain
2.4.18-rc1:

http://giga.cps.unizar.es/~magallon/linux/2.4.18-rc1-slb1/00-vm-24.gz



-- 
J.A. Magallon                           #  Let the source be with you...        
mailto:jamagallon@able.es
Mandrake Linux release 8.2 (Cooker) for i586
Linux werewolf 2.4.18-rc1-slb1 #1 SMP Thu Feb 14 01:04:12 CET 2002 i686