From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752625Ab0ENFuW (ORCPT ); Fri, 14 May 2010 01:50:22 -0400 Received: from 124x34x33x190.ap124.ftth.ucom.ne.jp ([124.34.33.190]:41725 "EHLO master.linux-sh.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186Ab0ENFuS (ORCPT ); Fri, 14 May 2010 01:50:18 -0400 Date: Fri, 14 May 2010 14:49:28 +0900 From: Paul Mundt To: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ak@linux.intel.com, fengguang.wu@intel.com, haicheng.li@linux.intel.com, shaohui.zheng@linux.intel.com Subject: Re: [RFC,5/7] NUMA hotplug emulator Message-ID: <20100514054928.GC12002@linux-sh.org> References: <20100513121457.GJ2169@shaohui> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100513121457.GJ2169@shaohui> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 13, 2010 at 08:14:57PM +0800, Shaohui Zheng wrote: > hotplug emulator: support cpu probe/release in x86 > > Add cpu interface probe/release under sysfs for x86. User can use this > interface to emulate the cpu hot-add process, it is for cpu hotplug > test purpose. Add a kernel option CONFIG_ARCH_CPU_PROBE_RELEASE for this > feature. > > This interface provides a mechanism to emulate cpu hotplug with software > methods, it becomes possible to do cpu hotplug automation and stress > testing. > At a quick glance, is this really necessary? It seems like you could easily replace most of this with a CPU notifier chain that takes care of the node handling. See for example how ppc64 manages the CPU hotplug/numa emulation case in arch/powerpc/mm/numa.c. arch_register_cpu() just looks like some topology hack for ACPI, it would be nice not to perpetuate that too much.