Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262245AbTH3XSx (ORCPT ); Sat, 30 Aug 2003 19:18:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262257AbTH3XSx (ORCPT ); Sat, 30 Aug 2003 19:18:53 -0400 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:40874 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S262245AbTH3XSv (ORCPT ); Sat, 30 Aug 2003 19:18:51 -0400 Date: Sun, 31 Aug 2003 01:19:04 +0200 From: Andrea Arcangeli To: Marcelo Tosatti Cc: Mike Fedyk , Antonio Vargas , lkml , Marc-Christian Petersen Subject: Re: Andrea VM changes Message-ID: <20030830231904.GL24409@dualathlon.random> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i 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 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2005 Lines: 51 On Sat, Aug 30, 2003 at 04:21:02PM -0300, Marcelo Tosatti wrote: > y > > On Sat, 30 Aug 2003, Marcelo Tosatti wrote: > > > > > > > Indeed, you are right. > > > > > > I'll start looking at them Monday. I'll keep you in touch. Thanks. > > > > Andrea, > > > > Would you mind to explain me 05_vm_06_swap_out-3 ? > > > > I see you change shrink_cache, try_to_free_pages_zone, etc. > > > > Can you please give me a detailed explanation of the changes there? > > > > I appreciate very much. > > > > I'll keep looking at other patches for now. > > 05_vm_09_misc_junk-3 removes the PF_MEMDIE and you also seem to remove the > OOM killer. Is that right? Why? because the oom killer is a DoS on servers, on a database setup, with 2G free, with say all tasks 2.7G large, it'll start killing all the thousand database tasks instead of the 2g netscape task that hit an userspace bug and it started allocating ram in a loop, and that will make no progress since no physical ram will be released. There's no need of oom killer to keep the system stable, with my vm, and the current probabilistic oom killer in the page fault hander kills the right task most of the time (unlike the stock oom killers that works well only for the desktops or developer machines). So it does a much better job and it doesn't risk to DoS the box due oom. Another DoS generated by the oom killer is that it'll try forever to kill a UNINTERRUPTIBLE task hanging in a nfs server that is down, so it hangs the whole box for an unlimited time. I've an algorithm that will work, and that will provide very good guarantees to kill the "best" task to make the machine usable again, with the needed protection against the security DoSes, but it's in no-way similar to the current oom killer. Andrea - 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/