From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 3D4CB6B0078 for ; Fri, 17 Sep 2010 03:32:38 -0400 (EDT) Message-Id: <1284708756.2702.1395472601@webmail.messagingengine.com> From: "Robert Mueller" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" In-Reply-To: <1284703264.3408.1.camel@sli10-conroe.sh.intel.com> References: <1284349152.15254.1394658481@webmail.messagingengine.com> <20100916184240.3BC9.A69D9226@jp.fujitsu.com> <1284684653.10161.1395434085@webmail.messagingengine.com> <1284703264.3408.1.camel@sli10-conroe.sh.intel.com> Reply-To: robm@fastmail.fm Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers Date: Fri, 17 Sep 2010 17:32:36 +1000 Sender: owner-linux-mm@kvack.org To: Shaohua Li Cc: Christoph Lameter , KOSAKI Motohiro , "linux-kernel@vger.kernel.org" , Bron Gondwana , linux-mm , Mel Gorman List-ID: > > I don't think this is any fault of how the software works. It's a > > *very* standard "pre-fork child processes, allocate incoming > > connections to a child process, open and mmap one or more files to > > read data from them". That's not exactly a weird programming model, > > and it's bad that the kernel is handling that case very badly with > > everything default. > > maybe you incoming connection always happen on one CPU and you do the > page allocation in that cpu, so some nodes use out of memory but > others have a lot free. Try bind the child process to different nodes > might help. There's are 5000+ child processes (it's a cyrus IMAP server). Neither the parent of any of the children are bound to any particular CPU. It uses a standard fcntl lock to make sure only one spare child at a time calls accept(). I don't think that's the problem. Rob -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org