From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 41B788D003B for ; Wed, 20 Apr 2011 03:15:29 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id D7DB13EE0C0 for ; Wed, 20 Apr 2011 16:15:25 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id BDD3345DE9F for ; Wed, 20 Apr 2011 16:15:25 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id A64B745DEA5 for ; Wed, 20 Apr 2011 16:15:25 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 8AFC11DB803C for ; Wed, 20 Apr 2011 16:15:25 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.240.81.147]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 506D2E18005 for ; Wed, 20 Apr 2011 16:15:25 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards In-Reply-To: References: <20110420102314.4604.A69D9226@jp.fujitsu.com> Message-Id: <20110420161615.462D.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Wed, 20 Apr 2011 16:15:23 +0900 (JST) Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: kosaki.motohiro@jp.fujitsu.com, Christoph Lameter , James Bottomley , Michal Hocko , Andrew Morton , Hugh Dickins , linux-mm@kvack.org, LKML , linux-parisc@vger.kernel.org, David Rientjes > 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. 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. I'm digging which fixing way has least risk. btw, x86 don't have an issue. Probably it's a reason why this issue was neglected long time. arch/x86/Kconfig ------------------------------------- config ARCH_DISCONTIGMEM_ENABLE def_bool y depends on NUMA && X86_32 -- 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