Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756911AbZAYMDb (ORCPT ); Sun, 25 Jan 2009 07:03:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752912AbZAYMDW (ORCPT ); Sun, 25 Jan 2009 07:03:22 -0500 Received: from out3.smtp.messagingengine.com ([66.111.4.27]:38827 "EHLO out3.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006AbZAYMDV (ORCPT ); Sun, 25 Jan 2009 07:03:21 -0500 Date: Sun, 25 Jan 2009 23:03:19 +1100 From: Bron Gondwana To: Greg KH Cc: Bron Gondwana , Linux Kernel Mailing List , stable@kernel.org, Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber Subject: Re: [patch 016/104] epoll: introduce resource usage limits Message-ID: <20090125120319.GA13869@brong.net> References: <20081203193901.715896543@mini.kroah.org> <20081203194849.GQ8950@kroah.com> <1232686261.9977.1296303473@webmail.messagingengine.com> <20090123051620.GA8122@suse.de> <1232704065.25510.1296328851@webmail.messagingengine.com> <20090123170631.GB11566@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090123170631.GB11566@suse.de> Organization: brong.net User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1386 Lines: 34 On Fri, Jan 23, 2009 at 09:06:31AM -0800, Greg KH wrote: > On Fri, Jan 23, 2009 at 08:47:45PM +1100, Bron Gondwana wrote: > > 1) is this value ever supposed to be hit in practice by non-malicious > > software? If not, it appears 128 is too low. > > It does appear a bit low. What looks to you like a good value to use as > a default? I've upgraded one production mx to 2.6.28.2 plus my latest patch (the rest are still running 2.6.27.6, which is prior to this limit) Here's some figures with my latest patch after about 10 minutes running to stabilise the startup figures: kvm virtual mx: 0 39 0 230 4096 271872 production mx: 0 207 107 1811 4096 266555 The interesting figure in each case is the second one, num_user_instances. Interesting that the UID is listed as 0 though, that's root! 107 is postfix, which makes sense. As you can see, the production mx would have start choking epolls almost immediately. These machines are about 5 years old now. 4Gb of memory, dual hyperthreading 32 bit Xeons. They're the least powerful machines we still keep running! Bron ( most of our costs are power and rack space, after all ) -- 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/