linux-kernel - Re: Hardcore trashing without any swap

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Date:	Fri, 11 Jun 2010 14:53:50 +0200
From:	László Monda <laci@...da.hu>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Hardcore trashing without any swap

On Fri, Jun 11, 2010 at 2:16 PM, Alan Cox <alan@...rguk.ukuu.org.uk> wrote:
> On Fri, 11 Jun 2010 02:10:33 +0200
> László Monda <laci@...da.hu> wrote:
>
>> Hi List,
>>
>> The problem I'm facing with is very simple, yet extremely irritating
>> in nature.  I have a laptop with 4G RAM and I don't use any swap.
>> Whenever the RAM is full my system keeps trashing.  This makes X and
>> SSH completely unresponsive for about a hour then a bunch of processes
>> gets killed and it's usable again.
>>
>> How is possible that my system is trashing even though I don't use any swap?
>
> Because you don't have any swap. Its having to dump stuff it doesn't want
> to like bits of applications that it can retrieve back from disk.

I can read what you wrote but cannot really understand it.  Please
tell me where my logic fails:

No swap -> no dedicated space on disk to dump stuff -> no disk I/O
should happen at all

>> I'd expect the kernel to immediately kill the largest process without
>> any trashing so I could continue my work right after the event.  How
>> is it possible to configure?
>
> It isn't.
>
> However if you want to avoid overcommit and thrashing play with
>
> /proc/sys/vm/overcommit*
>



-- 
László Monda <http://monda.hu>
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