From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 28E366B0078 for ; Fri, 17 Sep 2010 10:22:04 -0400 (EDT) Date: Fri, 17 Sep 2010 09:22:00 -0500 (CDT) From: Christoph Lameter Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers In-Reply-To: <20100917140916.GA8474@brong.net> Message-ID: 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> <1284708756.2702.1395472601@webmail.messagingengine.com> <20100917140916.GA8474@brong.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Bron Gondwana Cc: Robert Mueller , Shaohua Li , KOSAKI Motohiro , "linux-kernel@vger.kernel.org" , linux-mm , Mel Gorman List-ID: On Sat, 18 Sep 2010, Bron Gondwana wrote: > > From the first look that seems to be the problem. You do not need to be > > bound to a particular cpu, the scheduler will just leave a single process > > on the same cpu by default. If you then allocate all memory only from this > > process then you get the scenario that you described. > > Huh? Which bit of forking server makes you think one process is allocating > lots of memory? They're opening and reading from files. Unless you're > calling the kernel a "single process". I have no idea what your app does. The data that I glanced over looks as if most allocations happen for a particular memory node and since the memory is optimized to be local to that node other memory is not used intensively. This can occur because of allocations through one process / thread that is always running on the same cpu and therefore always allocates from the memory node local to that cpu. It can also happen f.e. if a driver always allocates memory local to the I/O bus that it is using. -- 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