Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756528AbaGWDSY (ORCPT ); Tue, 22 Jul 2014 23:18:24 -0400 Received: from mga02.intel.com ([134.134.136.20]:37664 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756429AbaGWDSU (ORCPT ); Tue, 22 Jul 2014 23:18:20 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,714,1400050800"; d="scan'208";a="577350575" Message-ID: <53CF2977.2040307@linux.intel.com> Date: Wed, 23 Jul 2014 11:18:15 +0800 From: Jiang Liu Organization: Intel User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Michal Hocko CC: Andrew Morton , Mel Gorman , David Rientjes , Mike Galbraith , Peter Zijlstra , "Rafael J . Wysocki" , Johannes Weiner , Tony Luck , linux-mm@kvack.org, linux-hotplug@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [RFC Patch V1 09/30] mm, memcg: Use cpu_to_mem()/numa_mem_id() to support memoryless node References: <1405064267-11678-1-git-send-email-jiang.liu@linux.intel.com> <1405064267-11678-10-git-send-email-jiang.liu@linux.intel.com> <20140718073614.GC21453@dhcp22.suse.cz> In-Reply-To: <20140718073614.GC21453@dhcp22.suse.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michal, Thanks for your comments! As discussed, we will rework the patch set in another direction to hide memoryless node from normal slab users. Regards! Gerry On 2014/7/18 15:36, Michal Hocko wrote: > On Fri 11-07-14 15:37:26, Jiang Liu wrote: >> When CONFIG_HAVE_MEMORYLESS_NODES is enabled, cpu_to_node()/numa_node_id() >> may return a node without memory, and later cause system failure/panic >> when calling kmalloc_node() and friends with returned node id. >> So use cpu_to_mem()/numa_mem_id() instead to get the nearest node with >> memory for the/current cpu. >> >> If CONFIG_HAVE_MEMORYLESS_NODES is disabled, cpu_to_mem()/numa_mem_id() >> is the same as cpu_to_node()/numa_node_id(). > > The change makes difference only for really tiny memcgs. If we really > have all pages on unevictable list or anon with no swap allowed and that > is the reason why no node is set in scan_nodes mask then reclaiming > memoryless node or any arbitrary close one doesn't make any difference. > The current memcg might not have any memory on that node at all. > > So the change doesn't make any practical difference and the changelog is > misleading. > >> Signed-off-by: Jiang Liu >> --- >> mm/memcontrol.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index a2c7bcb0e6eb..d6c4b7255ca9 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -1933,7 +1933,7 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) >> * we use curret node. >> */ >> if (unlikely(node == MAX_NUMNODES)) >> - node = numa_node_id(); >> + node = numa_mem_id(); >> >> memcg->last_scanned_node = node; >> return node; >> -- >> 1.7.10.4 >> > -- 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/