From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id EECFA6B004A for ; Thu, 18 Nov 2010 16:25:01 -0500 (EST) Received: from hpaq1.eem.corp.google.com (hpaq1.eem.corp.google.com [172.25.149.1]) by smtp-out.google.com with ESMTP id oAILOw6Q015868 for ; Thu, 18 Nov 2010 13:24:58 -0800 Received: from gyf2 (gyf2.prod.google.com [10.243.50.66]) by hpaq1.eem.corp.google.com with ESMTP id oAILOMuM006454 for ; Thu, 18 Nov 2010 13:24:56 -0800 Received: by gyf2 with SMTP id 2so2353592gyf.21 for ; Thu, 18 Nov 2010 13:24:56 -0800 (PST) Date: Thu, 18 Nov 2010 13:24:52 -0800 (PST) From: David Rientjes 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org 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 List-ID: 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, 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org