From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264461AbUGNEKi (ORCPT ); Wed, 14 Jul 2004 00:10:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265431AbUGNEKi (ORCPT ); Wed, 14 Jul 2004 00:10:38 -0400 Received: from mail-relay-2.tiscali.it ([213.205.33.42]:55774 "EHLO mail-relay-2.tiscali.it") by vger.kernel.org with ESMTP id S264461AbUGNEKe (ORCPT ); Wed, 14 Jul 2004 00:10:34 -0400 Date: Wed, 14 Jul 2004 06:10:26 +0200 From: Andrea Arcangeli To: Peter Zaitsev Cc: linux-kernel@vger.kernel.org Subject: Re: VM Problems in 2.6.7 (Too active OOM Killer) Message-ID: <20040714041026.GX974@dualathlon.random> References: <1089771823.15336.2461.camel@abyss.home> <20040714031701.GT974@dualathlon.random> <1089776640.15336.2557.camel@abyss.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1089776640.15336.2557.camel@abyss.home> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 13, 2004 at 08:44:02PM -0700, Peter Zaitsev wrote: > The reason for me to disable swap both in 2.4 and 2.6 is - it really > hurts performance. In some cases performance can be 2-3 times slower > with swap file enabled. Using O_DIRECT and mlock() for buffers helps > but not completely. in 2.4 you can disable swap just fine (with oom killer disabled). until I/somebody fix 2.6 you can workaround this problem while still avoiding to swap much by setting /proc/sys/vm/swappiness to 0 or similar to tell the VM "please don't swap" even if swap is enabled ;). That will still prevent the oom killer to kick in. The oom killer is forbidden to run as long as `free` tells you that >= 4k of swap are still available to the OS. There are no other fundamental vm problems left I'm aware of in latest 2.6 besides these no-swap and oom issues.