Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945961Ab2JaSQl (ORCPT ); Wed, 31 Oct 2012 14:16:41 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:61859 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935727Ab2JaSQi (ORCPT ); Wed, 31 Oct 2012 14:16:38 -0400 Date: Wed, 31 Oct 2012 11:16:35 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Wen Congyang cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, Rob Landley , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , Yinghai Lu , "rusty@rustcorp.com.au" Subject: Re: [PART3 Patch 00/14] introduce N_MEMORY In-Reply-To: <1351670652-9932-1-git-send-email-wency@cn.fujitsu.com> Message-ID: References: <1351670652-9932-1-git-send-email-wency@cn.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1414 Lines: 36 On Wed, 31 Oct 2012, Wen Congyang wrote: > From: Lai Jiangshan > > This patch is part3 of the following patchset: > https://lkml.org/lkml/2012/10/29/319 > > Part1 is here: > https://lkml.org/lkml/2012/10/31/30 > > Part2 is here: > http://marc.info/?l=linux-kernel&m=135166705909544&w=2 > > You can apply this patchset without the other parts. > > we need a node which only contains movable memory. This feature is very > important for node hotplug. So we will add a new nodemask > for all memory. N_MEMORY contains movable memory but N_HIGH_MEMORY > doesn't contain it. > > We don't remove N_HIGH_MEMORY because it can be used to search which > nodes contains memory that the kernel can use. > This doesn't describe why we need the new node state, unfortunately. It makes sense to boot with node(s) containing only ZONE_MOVABLE, but it doesn't show why we need a nodemask to specify such nodes and such information should be available from the kernel log or /proc/zoneinfo. Node hotplug should fail if all memory cannot be offlined, so why do we need another nodemask? Only offline the node if all memory is offlined. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/