Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755577AbZLWKKY (ORCPT ); Wed, 23 Dec 2009 05:10:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754969AbZLWKKX (ORCPT ); Wed, 23 Dec 2009 05:10:23 -0500 Received: from gw1.cosmosbay.com ([212.99.114.194]:57839 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754891AbZLWKKW (ORCPT ); Wed, 23 Dec 2009 05:10:22 -0500 Message-ID: <4B31EC7C.7000302@gmail.com> Date: Wed, 23 Dec 2009 11:10:04 +0100 From: Eric Dumazet User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.1.5) Gecko/20091204 Thunderbird/3.0 MIME-Version: 1.0 To: Haicheng Li CC: Christoph Lameter , linux-mm@kvack.org, Pekka Enberg , Matt Mackall , andi@firstfloor.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] slab: initialize unused alien cache entry as NULL at alloc_alien_cache(). References: <4B30BDA8.1070904@linux.intel.com> <4B31BE44.1070308@linux.intel.com> In-Reply-To: <4B31BE44.1070308@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [0.0.0.0]); Wed, 23 Dec 2009 11:10:04 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1143 Lines: 33 Le 23/12/2009 07:52, Haicheng Li a ?crit : > Christoph & Matt, > > Thanks for the review. Node ids beyond nr_node_ids could be used in the > case of > memory hotadding. > > Let me explain here: > Firstly, original nr_node_ids = 1 + nid of highest POSSIBLE node. > > Secondly, consider hotplug-adding the memories that are on a new_added > node: > 1. when acpi event is triggered: > acpi_memory_device_add() -> acpi_memory_enable_device() -> add_memory() > -> node_set_online() > > The node_state[N_ONLINE] is updated with this new node added. > And the id of this new node is beyond nr_node_ids. > Then, this is a violation of the first statement : nr_node_ids = 1 + nid of highest POSSIBLE node. If your system allows hotplugging of new nodes, then POSSIBLE nodes should include them at boot time. Same thing for cpus and nr_cpus_ids. If a cpu is added, then its id MUST be < nr_cpus_ids -- 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/