From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 219B98D003B for ; Wed, 20 Apr 2011 03:41:22 -0400 (EDT) Received: by yib18 with SMTP id 18so183187yib.14 for ; Wed, 20 Apr 2011 00:41:20 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110420161615.462D.A69D9226@jp.fujitsu.com> References: <20110420102314.4604.A69D9226@jp.fujitsu.com> <20110420161615.462D.A69D9226@jp.fujitsu.com> Date: Wed, 20 Apr 2011 10:34:23 +0300 Message-ID: Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Christoph Lameter , James Bottomley , Michal Hocko , Andrew Morton , Hugh Dickins , linux-mm@kvack.org, LKML , linux-parisc@vger.kernel.org, David Rientjes , Ingo Molnar , x86 maintainers Hi! On Wed, Apr 20, 2011 at 4:23 AM, KOSAKI Motohiro >> wrote: >> > I'm worry about this patch. A lot of mm code assume !NUMA systems >> > only have node 0. Not only SLUB. >> >> So is that a valid assumption or not? Christoph seems to think it is >> and James seems to think it's not. Which way should we aim to fix it? >> Would be nice if other people chimed in as we already know what James >> and Christoph think. On Wed, Apr 20, 2011 at 10:15 AM, KOSAKI Motohiro wrote: > I'm sorry. I don't know it really. The fact was gone into historical myst= . ;-) > > Now, CONFIG_NUMA has mainly five meanings. > > 1) system may has !0 node id. > 2) compile mm/mempolicy.c (ie enable mempolicy APIs) > 3) Allocator (kmalloc, vmalloc, alloc_page, et al) awake NUMA topology. > 4) enable zone-reclaim feature > 5) scheduler makes per-node load balancing scheduler domain > > Anyway, we have to fix this issue. =A0I'm digging which fixing way has le= ast risk. > > > btw, x86 don't have an issue. Probably it's a reason why this issue was n= eglected > long time. > > arch/x86/Kconfig > ------------------------------------- > config ARCH_DISCONTIGMEM_ENABLE > =A0 =A0 =A0 =A0def_bool y > =A0 =A0 =A0 =A0depends on NUMA && X86_32 That part makes me think the best option is to make parisc do CONFIG_NUMA as well regardless of the historical intent was. Pekka -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org