From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753203AbXCWF5r (ORCPT ); Fri, 23 Mar 2007 01:57:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933675AbXCWF5r (ORCPT ); Fri, 23 Mar 2007 01:57:47 -0400 Received: from smtp103.mail.mud.yahoo.com ([209.191.85.213]:35422 "HELO smtp103.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753176AbXCWF5q (ORCPT ); Fri, 23 Mar 2007 01:57:46 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=P/W73KKhPmLvSCcVAlmtmojnZvd1pRPZHbFCmX0UoEiswtrjx0Hv2/v+HU262dP+HgkPVwJooWUCuj4Tw1WrpOY9YwwB9fKqdSq71k7UJ+KQ6p0ZO+/sBNwx3HH5PfsjVFCY6w29Dz1nHoxUJ+yXO2+MUuizEp/Mus8uQ52k5A4= ; X-YMail-OSG: ckCRW5UVM1mhFmf6fOOydb0e.o4s3ADVuYmWBLKqROlESk9FIu6DPU8H2u8GjVESS9Ldv7RAWAXTzkq.DpzOT3J4nrbmaZNFqHNGuSFKP7sTpS_L1WJcmYi4CbkBGSN9ujSu2gpIN6ADYLWdS_Rl8DYXWA-- Message-ID: <46036C54.6030502@yahoo.com.au> Date: Fri, 23 Mar 2007 16:57:40 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: "Eric W. Biederman" CC: Dave Hansen , Alan Cox , containers@lists.osdl.org, linux-kernel@vger.kernel.org, menage@google.com, Andrew Morton , xemul@sw.ru Subject: Re: controlling mmap()'d vs read/write() pages References: <45ED7DEC.7010403@sw.ru> <45ED80E1.7030406@sw.ru> <20070306140036.4e85bd2f.akpm@linux-foundation.org> <45F3F581.9030503@sw.ru> <20070311045111.62d3e9f9.akpm@linux-foundation.org> <20070312010039.GC21861@MAIL.13thfloor.at> <1173724979.11945.103.camel@localhost.localdomain> <20070312224129.GC21258@MAIL.13thfloor.at> <20070312220439.677b4787.akpm@linux-foundation.org> <1173806793.6680.44.camel@localhost.localdomain> <20070313190931.1417c012@lxorguk.ukuu.org.uk> <1174062660.8184.8.camel@localhost.localdomain> <1174074412.8184.29.camel@localhost.localdomain> <1174407335.26166.146.camel@localhost.localdomain> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric W. Biederman wrote: > Dave Hansen writes: > > >>So, I think we have a difference of opinion. I think it's _all_ about >>memory pressure, and you think it is _not_ about accounting for memory >>pressure. :) Perhaps we mean different things, but we appear to >>disagree greatly on the surface. > > > I think it is about preventing a badly behaved container from having a > significant effect on the rest of the system, and in particular other > containers on the system. That's Dave's point, I believe. Limiting mapped memory may be mostly OK for well behaved applications, but it doesn't do anything to stop bad ones from effectively DoSing the system or ruining any guarantees you might proclaim (not that hard guarantees are always possible without using virtualisation anyway). This is why I'm surprised at efforts that go to such great lengths to get accounting "just right" (but only for mmaped memory). You may as well not even bother, IMO. Give me an RSS limit big enough to run a couple of system calls and a loop... -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com