Date: Thu, 7 Oct 2004 22:05:39 -0300
From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: Marc-Christian Petersen <m.c.p@kernel.linux-systeme.com>
Cc: "Gabor Z. Papp" <gzp@papp.hu>, Michael Buesch <mbuesch@freenet.de>,
       linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [2.4] 0-order allocation failed
Message-ID: <20041008010539.GB16968@logos.cnet>
References: <200410071318.21091.mbuesch@freenet.de> <20041007153929.GB14614@logos.cnet> <x67jq2bcy3@gzp> <200410072054.17097@WOLK>
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On Thu, Oct 07, 2004 at 08:54:16PM +0200, Marc-Christian Petersen wrote:
> On Thursday 07 October 2004 20:28, Gabor Z. Papp wrote:
> 
> Hi all,
> 
> > | > > Can you check how much swap space is there available when
> > | > > the OOM killer trigger? I bet this is the case.
> > | > The machine doesn't have swap.
> > | Well then you're probably facing true OOM.
> > | Add some swap.
> 
> > There is really no way to run 2.4 without swap?
> > I have the same problem with nfsroot and ramdisk based setups after
> > 1-2 weeks uptime.
> 
> stop whining about braindead 2.4 mainline vm. Apply the attached patch and be 
> happy :p

As I told you in private, I can't see how badly this patch could affect performance.
But then, as you answered, with all anonymous pages added to LRU you see much better
behavior (tons less swapping) on several workloads. That must be due to 
refill_inactive()/shrink_cache() balancing.

The same patch also fixes kswapd excessive CPU consumption on huge
memory box.

Its easy enough to be applied because behaviour is unchanged by default
(you need to change a sysctl value for that).

I would like to understand why does it cause so much improved behaviour
though.

> Marcelo: Is there something wrong with my VM documentation update patches for 
> 2.4? Or do you not care and think: "Hello my friend, let's stick with 2.2 VM 
> documentation even if almost all of the documentation is not longer valid"

As I said to you in private, please resend.

Thanks!
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