From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 760496B0012 for ; Fri, 27 May 2011 19:40:10 -0400 (EDT) Date: Sat, 28 May 2011 01:40:07 +0200 From: Michal Hocko Subject: Re: [PATCH v2] cpusets: randomize node rotor used in cpuset_mem_spread_node() Message-ID: <20110527234007.GB4276@tiehlicka.suse.cz> References: <20110414065146.GA19685@tiehlicka.suse.cz> <20110414160145.0830.A69D9226@jp.fujitsu.com> <20110415161831.12F8.A69D9226@jp.fujitsu.com> <20110415082051.GB8828@tiehlicka.suse.cz> <20110526153319.b7e8c0b6.akpm@linux-foundation.org> <20110527124705.GB4067@tiehlicka.suse.cz> <20110527231708.GB3214@tiehlicka.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , KOSAKI Motohiro , LKML , Jack Steiner , Lee Schermerhorn , Christoph Lameter , Pekka Enberg , Paul Menage , Robin Holt , Linus Torvalds , linux-mm@kvack.org On Fri 27-05-11 16:27:34, David Rientjes wrote: > On Sat, 28 May 2011, Michal Hocko wrote: > > > > CONFIG_NODES_SHIFT is used for UMA machines that are using DISCONTIGMEM > > > usually because they have very large holes; such machines don't need > > > things like mempolicies but do need the data structures that abstract > > > ranges of memory in the physical address space. This build breakage > > > probably isn't restricted to only alpha, you could probably see it with at > > > least ia64 and mips as well. > > > > Hmmm. I just find strange that some UMA arch uses functions like > > {first,next}_online_node. > > > > They shouldn't, but they do use NUMA data structures like pg_data_t for > DISCONTIGMEM. The MAX_NUMNODES > 1 optimization in nodemask.h is to > prevent doing things like node_weight() on a nodemask when we know that > only one bit will ever be set, otherwise we could make it conditional on > CONFIG_NEED_MULTIPLE_NODES. Thanks for the explanation. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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