From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934859Ab0BZBNV (ORCPT ); Thu, 25 Feb 2010 20:13:21 -0500 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:40959 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934840Ab0BZBNU (ORCPT ); Thu, 25 Feb 2010 20:13:20 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Fri, 26 Feb 2010 10:09:44 +0900 From: KAMEZAWA Hiroyuki To: Christoph Lameter Cc: David Rientjes , Pekka Enberg , Andi Kleen , Nick Piggin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haicheng.li@intel.com Subject: Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache_reap Message-Id: <20100226100944.1c2aa738.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20100211953.850854588@firstfloor.org> <20100211205404.085FEB1978@basil.firstfloor.org> <20100215061535.GI5723@laptop> <20100215103250.GD21783@one.firstfloor.org> <20100215104135.GM5723@laptop> <20100215105253.GE21783@one.firstfloor.org> <20100215110135.GN5723@laptop> <20100220090154.GB11287@basil.fritz.box> <4B862623.5090608@cs.helsinki.fi> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.7.1 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Feb 2010 12:30:26 -0600 (CST) Christoph Lameter wrote: > On Thu, 25 Feb 2010, David Rientjes wrote: > > > I don't see how memory hotadd with a new node being onlined could have > > worked fine before since slab lacked any memory hotplug notifier until > > Andi just added it. > > AFAICR The cpu notifier took on that role in the past. > > If what you say is true then memory hotplug has never worked before. > Kamesan? > In this code, int node = numa_node_id(); node is got by its CPU. At node hotplug, following order should be kept. Add: memory -> cpu Remove: cpu -> memory cpus must be onlined after memory. At least, we online cpus only after memory. Then, we(our heavy test on RHEL5) never see this kind of race. I'm sorry if my answer misses your point. Thanks, -Kame > -- > 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/ > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 272EC6B0047 for ; Thu, 25 Feb 2010 20:13:23 -0500 (EST) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o1Q1DJdf023207 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Fri, 26 Feb 2010 10:13:19 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 0872545DE4F for ; Fri, 26 Feb 2010 10:13:19 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m5.gw.fujitsu.co.jp (Postfix) with ESMTP id D8FC845DE54 for ; Fri, 26 Feb 2010 10:13:18 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id BA3A71DB8038 for ; Fri, 26 Feb 2010 10:13:18 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 765231DB803C for ; Fri, 26 Feb 2010 10:13:18 +0900 (JST) Date: Fri, 26 Feb 2010 10:09:44 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache_reap Message-Id: <20100226100944.1c2aa738.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20100211953.850854588@firstfloor.org> <20100211205404.085FEB1978@basil.firstfloor.org> <20100215061535.GI5723@laptop> <20100215103250.GD21783@one.firstfloor.org> <20100215104135.GM5723@laptop> <20100215105253.GE21783@one.firstfloor.org> <20100215110135.GN5723@laptop> <20100220090154.GB11287@basil.fritz.box> <4B862623.5090608@cs.helsinki.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: David Rientjes , Pekka Enberg , Andi Kleen , Nick Piggin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haicheng.li@intel.com List-ID: On Thu, 25 Feb 2010 12:30:26 -0600 (CST) Christoph Lameter wrote: > On Thu, 25 Feb 2010, David Rientjes wrote: > > > I don't see how memory hotadd with a new node being onlined could have > > worked fine before since slab lacked any memory hotplug notifier until > > Andi just added it. > > AFAICR The cpu notifier took on that role in the past. > > If what you say is true then memory hotplug has never worked before. > Kamesan? > In this code, int node = numa_node_id(); node is got by its CPU. At node hotplug, following order should be kept. Add: memory -> cpu Remove: cpu -> memory cpus must be onlined after memory. At least, we online cpus only after memory. Then, we(our heavy test on RHEL5) never see this kind of race. I'm sorry if my answer misses your point. Thanks, -Kame > -- > 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/ > -- 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/ . Don't email: email@kvack.org