From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261447AbVGWSpw (ORCPT ); Sat, 23 Jul 2005 14:45:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261453AbVGWSpw (ORCPT ); Sat, 23 Jul 2005 14:45:52 -0400 Received: from mx1.redhat.com ([66.187.233.31]:6554 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S261447AbVGWSpu (ORCPT ); Sat, 23 Jul 2005 14:45:50 -0400 Date: Sat, 23 Jul 2005 14:45:40 -0400 From: Neil Horman To: =?iso-8859-1?Q?M=E1rcio?= Oliveira Cc: Roger Heflin , "'Neil Horman'" , arjanv@redhat.com, linux-kernel@vger.kernel.org Subject: Re: Memory Management Message-ID: <20050723184540.GA1670@hmsendeavour.rdu.redhat.com> References: <42E17FE7.3030205@latinsourcetech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <42E17FE7.3030205@latinsourcetech.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 22, 2005 at 08:23:19PM -0300, Márcio Oliveira wrote: > > > Roger, thanks for the information. > > I'm using Update 4 kernels (2.4.21-27.ELsmp - This kernel have some > mm / oom fixes) and don't have big problems when create large files, > plus the server is a 32-bit machine. > > Neil said that the problem can be Low Memory and I think it too. > > I read the following message on the list: > > http://marc.theaimsgroup.com/?l=linux-kernel&m=112044530919567&w=4 > > The problem seems like a I/O issue. Can I/O (like storage devices) > consume a large amount of low memory? Neil also said that the kernel is > trying to move lots of data to the disk and it's a module might require > such large memory. Somebody know how can I identify what is using Low > Memory on my system? > The best way I can think to do that is take a look at /proc/slabinfo. That will likely give you a pointer to which area of code is eating up your memory. > The older questions in the message are: > > The server has 16GB RAM and 16GB swap. When the OOM kill conditions > happens, the system has ~6GB RAM used, ~10GB RAM cached and 16GB free swap. > Is that indicate that the server can't allocate Low Memory and starts OOM > conditions? Because the High Memory is OK, right? > Based on the sysrq-m info you posted it looks like due to fragmentation the largest chunk of memory you can allocate is 2MB (perhaps less depending on address space availability). If you can build a test kernel to do a show_state rather than a show_mem at the beginning of oom_kil, then you should be able to tell who is trying to do an allocation that leads to kswapd calling out_of_memory. > Thanks to all! > > Regards, > Márcio > > -- /*************************************************** *Neil Horman *Software Engineer *Red Hat, Inc. *nhorman@redhat.com *gpg keyid: 1024D / 0x92A74FA1 *http://pgp.mit.edu ***************************************************/