Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760478Ab0KRVZA (ORCPT ); Thu, 18 Nov 2010 16:25:00 -0500 Received: from smtp-out.google.com ([74.125.121.35]:37133 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759303Ab0KRVY7 (ORCPT ); Thu, 18 Nov 2010 16:24:59 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; b=kcoy47QXrnjYHiCFKmxY7zEhbTTUacCLwSUFO7Z166+XWx3xfoYqN2CAV3WbExUjBe 2zIRk5Z24v2T/sHqMv1A== Date: Thu, 18 Nov 2010 13:24:52 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Shaohui Zheng cc: Paul Mundt , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, haicheng.li@linux.intel.com, ak@linux.intel.com, shaohui.zheng@linux.intel.com, Yinghai Lu , Haicheng Li Subject: Re: [2/8,v3] NUMA Hotplug Emulator: infrastructure of NUMA hotplug emulation In-Reply-To: <20101118052750.GD2408@shaohui> Message-ID: References: <20101117020759.016741414@intel.com> <20101117021000.568681101@intel.com> <20101117075128.GA30254@shaohui> <20101118041407.GA2408@shaohui> <20101118062715.GD17539@linux-sh.org> <20101118052750.GD2408@shaohui> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1244 Lines: 24 On Thu, 18 Nov 2010, Shaohui Zheng wrote: > in our draft patch, we re-setup nr_node_ids when CONFIG_ARCH_MEMORY_PROBE enabled > and mem=XXX was specified in grub. we set nr_node_ids as MAX_NUMNODES + 1, because > we do not know how many nodes will be hot-added through memory/probe interface. > it might be a little wasting of memory. > nr_node_ids need not be set to anything different at boot, the MEM_GOING_ONLINE callback should be used for anything (like the slab allocators) where a new node is introduced and needs to be dealt with accordingly; this is how regular memory hotplug works, we need no additional code in this regard because it's emulated. If a subsystem needs to change in response to a new node going online and doesn't as a result of using your emulator, that's a bug and either needs to be fixed or prohibited from use with CONFIG_MEMORY_HOTPLUG. (See the MEM_GOING_ONLINE callback in mm/slub.c, for instance, which deals only with the case of node hotplug.) -- 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/