From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 236B96B0047 for ; Mon, 4 Oct 2010 09:07:47 -0400 (EDT) Date: Mon, 4 Oct 2010 08:07:42 -0500 (CDT) From: Christoph Lameter Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers In-Reply-To: <20101004211112.E8B1.A69D9226@jp.fujitsu.com> Message-ID: References: <20100927110049.6B31.A69D9226@jp.fujitsu.com> <20101004211112.E8B1.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Mel Gorman , Rob Mueller , linux-kernel@vger.kernel.org, Bron Gondwana , linux-mm List-ID: On Mon, 4 Oct 2010, KOSAKI Motohiro wrote: > > The problem with zone reclaim mainly is created for large apps whose > > working set is larger than the local node. The special settings are only > > needing for those applications. > > In theory, yes. but please talk with userland developers. They always say > "Our software work fine on *BSD, Solaris, Mac, etc etc. that's definitely > linux problem". /me have no way to persuade them ;-) Do those support NUMA? I would think not. You would have to switch on interleave at the BIOS level (getting a hardware hack in place to get rid of the NUMA effects) to make these OSes run right. > This is one of option. but we don't need to create x86 arch specific > RECLAIM_DISTANCE. Because practical high-end numa machine are either > ia64(SGI, Fujitsu) or Power(IBM) and both platform already have arch > specific definition. then changing RECLAIM_DISTANCE doesn't make any > side effect on such platform. and if possible, x86 shouldn't have > arch specific definition because almost minor arch don't have a lot of > tester and its quality often depend on testing on x86. > > attached a patch below. Looks good. Acked-by: Christoph Lameter -- 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