From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753579AbdGNJsR (ORCPT ); Fri, 14 Jul 2017 05:48:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:55884 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751366AbdGNJsQ (ORCPT ); Fri, 14 Jul 2017 05:48:16 -0400 Date: Fri, 14 Jul 2017 10:48:10 +0100 From: Mel Gorman To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , Johannes Weiner , Vlastimil Babka , LKML , Michal Hocko Subject: Re: [PATCH 3/9] mm, page_alloc: do not set_cpu_numa_mem on empty nodes initialization Message-ID: <20170714094810.ftthctfz33artwh2@suse.de> References: <20170714080006.7250-1-mhocko@kernel.org> <20170714080006.7250-4-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20170714080006.7250-4-mhocko@kernel.org> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 14, 2017 at 10:00:00AM +0200, Michal Hocko wrote: > From: Michal Hocko > > __build_all_zonelists reinitializes each online cpu local node for > CONFIG_HAVE_MEMORYLESS_NODES. This makes sense because previously memory > less nodes could gain some memory during memory hotplug and so the local > node should be changed for CPUs close to such a node. It makes less > sense to do that unconditionally for a newly creaded NUMA node which is > still offline and without any memory. > > Let's also simplify the cpu loop and use for_each_online_cpu instead of > an explicit cpu_online check for all possible cpus. > > Signed-off-by: Michal Hocko > --- > mm/page_alloc.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 7746824a425d..ebc3311555b1 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5096,10 +5096,8 @@ static int __build_all_zonelists(void *data) > > build_zonelists(pgdat); > } > - } > > #ifdef CONFIG_HAVE_MEMORYLESS_NODES > - for_each_possible_cpu(cpu) { > /* > * We now know the "local memory node" for each node-- > * i.e., the node of the first zone in the generic zonelist. > @@ -5108,10 +5106,10 @@ static int __build_all_zonelists(void *data) > * secondary cpus' numa_mem as they come on-line. During > * node/memory hotplug, we'll fixup all on-line cpus. > */ > - if (cpu_online(cpu)) > + for_each_online_cpu(cpu) > set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); > - } > #endif > + } > This is not as clear a benefit. For each online node, we now go through all online CPUs once per node. There would be some rationale for using for_each_online_cpu. -- Mel Gorman SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id A7E18440905 for ; Fri, 14 Jul 2017 05:48:16 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id c81so8414423wmd.10 for ; Fri, 14 Jul 2017 02:48:16 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id u48si6218115wrb.323.2017.07.14.02.48.15 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 14 Jul 2017 02:48:15 -0700 (PDT) Date: Fri, 14 Jul 2017 10:48:10 +0100 From: Mel Gorman Subject: Re: [PATCH 3/9] mm, page_alloc: do not set_cpu_numa_mem on empty nodes initialization Message-ID: <20170714094810.ftthctfz33artwh2@suse.de> References: <20170714080006.7250-1-mhocko@kernel.org> <20170714080006.7250-4-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20170714080006.7250-4-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , Johannes Weiner , Vlastimil Babka , LKML , Michal Hocko On Fri, Jul 14, 2017 at 10:00:00AM +0200, Michal Hocko wrote: > From: Michal Hocko > > __build_all_zonelists reinitializes each online cpu local node for > CONFIG_HAVE_MEMORYLESS_NODES. This makes sense because previously memory > less nodes could gain some memory during memory hotplug and so the local > node should be changed for CPUs close to such a node. It makes less > sense to do that unconditionally for a newly creaded NUMA node which is > still offline and without any memory. > > Let's also simplify the cpu loop and use for_each_online_cpu instead of > an explicit cpu_online check for all possible cpus. > > Signed-off-by: Michal Hocko > --- > mm/page_alloc.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 7746824a425d..ebc3311555b1 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5096,10 +5096,8 @@ static int __build_all_zonelists(void *data) > > build_zonelists(pgdat); > } > - } > > #ifdef CONFIG_HAVE_MEMORYLESS_NODES > - for_each_possible_cpu(cpu) { > /* > * We now know the "local memory node" for each node-- > * i.e., the node of the first zone in the generic zonelist. > @@ -5108,10 +5106,10 @@ static int __build_all_zonelists(void *data) > * secondary cpus' numa_mem as they come on-line. During > * node/memory hotplug, we'll fixup all on-line cpus. > */ > - if (cpu_online(cpu)) > + for_each_online_cpu(cpu) > set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); > - } > #endif > + } > This is not as clear a benefit. For each online node, we now go through all online CPUs once per node. There would be some rationale for using for_each_online_cpu. -- Mel Gorman SUSE Labs -- 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