From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f180.google.com (mail-wi0-f180.google.com [209.85.212.180]) by kanga.kvack.org (Postfix) with ESMTP id 107136B0253 for ; Thu, 27 Aug 2015 05:29:56 -0400 (EDT) Received: by widdq5 with SMTP id dq5so71825898wid.1 for ; Thu, 27 Aug 2015 02:29:55 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id tn8si2899047wjc.133.2015.08.27.02.29.53 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 27 Aug 2015 02:29:54 -0700 (PDT) Subject: Re: [PATCH V3] mm: memory hot-add: memory can not be added to movable zone defaultly References: <1440665641-3839-1-git-send-email-liuchangsheng@inspur.com> From: Vlastimil Babka Message-ID: <55DED890.4020200@suse.cz> Date: Thu, 27 Aug 2015 11:29:52 +0200 MIME-Version: 1.0 In-Reply-To: <1440665641-3839-1-git-send-email-liuchangsheng@inspur.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Changsheng Liu , akpm@linux-foundation.org, isimatu.yasuaki@jp.fujitsu.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, wunan@inspur.com, yanxiaofeng@inspur.com, fandd@inspur.com, Changsheng Liu On 08/27/2015 10:54 AM, Changsheng Liu wrote: > From: Changsheng Liu > > After the user config CONFIG_MOVABLE_NODE and movable_node kernel option, > When the memory is hot added, should_add_memory_movable() return 0 > because all zones including movable zone are empty, > so the memory that was hot added will be added to the normal zone > and the normal zone will be created firstly. > But we want the whole node to be added to movable zone defaultly. OK it seems current behavior indeed goes against the expectations of setting movable_node. > So we change should_add_memory_movable(): if the user config > CONFIG_MOVABLE_NODE and movable_node kernel option > it will always return 1 and all zones is empty at the same time, > so that the movable zone will be created firstly > and then the whole node will be added to movable zone defaultly. > If we want the node to be added to normal zone, > we can do it as follows: > "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" > > If the memory is added to movable zone defaultly, > the user can offline it and add it to other zone again. Was this tested to really work as well? Per Yasuaki's explanation in v2, you shouldn't create ZONE_MOVABLE before ZONE_NORMAL. > But if the memory is added to normal zone defaultly, > the user will not offline the memory used by kernel. > > Reviewed-by: Andrew Morton Interesting... > Signed-off-by: Changsheng Liu i > Tested-by: Dongdong Fan > --- > mm/memory_hotplug.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 26fbba7..b5f14fa 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1198,6 +1198,9 @@ static int should_add_memory_movable(int nid, u64 start, u64 size) > pg_data_t *pgdat = NODE_DATA(nid); > struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; > > + if (movable_node_is_enabled()) > + return 1; > + > if (zone_is_empty(movable_zone)) > return 0; > > -- 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