Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755449Ab2HTHBk (ORCPT ); Mon, 20 Aug 2012 03:01:40 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:3625 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752375Ab2HTHBf (ORCPT ); Mon, 20 Aug 2012 03:01:35 -0400 X-IronPort-AV: E=Sophos;i="4.77,796,1336320000"; d="scan'208";a="5670424" Message-ID: <5031E208.2080202@cn.fujitsu.com> Date: Mon, 20 Aug 2012 15:06:48 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: wujianguo CC: tony.luck@intel.com, fenghua.yu@intel.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, jiang.liu@huawei.com, guohanjun@huawei.com, qiuxishi@huawei.com, liuj97@gmail.com Subject: Re: [PATCH]mm/ia64: fix a node distance bug References: <5031D763.9010808@gmail.com> In-Reply-To: <5031D763.9010808@gmail.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/08/20 15:01:36, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/08/20 15:01:37, Serialize complete at 2012/08/20 15:01:37 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2645 Lines: 81 At 08/20/2012 02:21 PM, wujianguo Wrote: > From: Jianguo Wu > > Hi all, > When doing memory-hot-plug, We found node distance is wrong after offline > a node in IA64 platform. For example system has 4 nodes: > node distances: > node 0 1 2 3 > 0: 10 21 21 32 > 1: 21 10 32 21 > 2: 21 32 10 21 > 3: 32 21 21 10 > > linux-drf:/sys/devices/system/node/node0 # cat distance > 10 21 21 32 > linux-drf:/sys/devices/system/node/node1 # cat distance > 21 10 32 21 > > After offline node2: > linux-drf:/sys/devices/system/node/node0 # cat distance > 10 21 32 > linux-drf:/sys/devices/system/node/node1 # cat distance > 32 21 32 --------->expected value is: 21 10 21 > > In arch IA, we have following definition: > extern u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES]; > #define node_distance(from,to) (numa_slit[(from) * num_online_nodes() + (to)]) > > node distance is setup as following: > acpi_numa_arch_fixup() > { > ... > memset(numa_slit, -1, sizeof(numa_slit)); > for (i = 0; i < slit_table->locality_count; i++) { > if (!pxm_bit_test(i)) > continue; > node_from = pxm_to_node(i); > for (j = 0; j < slit_table->locality_count; j++) { > if (!pxm_bit_test(j)) > continue; > node_to = pxm_to_node(j); > node_distance(node_from, node_to) = > slit_table->entry[i * slit_table->locality_count + j]; > } > } > ... > } > num_online_nodes() is a variable value, during system boot the return vale is 4, > but after offline node2, the return value is 3, so we read a wrong node distance value. > This patch is trying to fix this bug. > > Signed-off-by: Jianguo Wu > --- > arch/ia64/include/asm/numa.h | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/ia64/include/asm/numa.h b/arch/ia64/include/asm/numa.h > index 6a8a27c..2e27ef1 100644 > --- a/arch/ia64/include/asm/numa.h > +++ b/arch/ia64/include/asm/numa.h > @@ -59,7 +59,7 @@ extern struct node_cpuid_s node_cpuid[NR_CPUS]; > */ > > extern u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES]; > -#define node_distance(from,to) (numa_slit[(from) * num_online_nodes() + (to)]) > +#define node_distance(from,to) (numa_slit[(from) * MAX_NUMNODES + (to)]) Hmm, MAX_NUMNODES is too large. I think num_possible_nodes() is better. Thanks Wen Congyang > > extern int paddr_to_nid(unsigned long paddr); > -- 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/