From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f44.google.com (mail-qg0-f44.google.com [209.85.192.44]) by kanga.kvack.org (Postfix) with ESMTP id 7F6449003C7 for ; Tue, 25 Aug 2015 20:39:41 -0400 (EDT) Received: by qgeg42 with SMTP id g42so117909027qge.1 for ; Tue, 25 Aug 2015 17:39:41 -0700 (PDT) Received: from bgp253.corp-email.cn (bgp253.corp-email.cn. [112.65.243.253]) by mx.google.com with ESMTPS id l84si35901802qhl.115.2015.08.25.17.39.39 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 25 Aug 2015 17:39:40 -0700 (PDT) Subject: Re: [PATCH V2] mm:memory hot-add: memory can not been added to movable zone References: <1440055685-6083-1-git-send-email-liuchangsheng@inspur.com> <55dc69b5.46268c0a.faa78.24eb@mx.google.com> From: Changsheng Liu Message-ID: <55DD0A99.5080803@inspur.com> Date: Wed, 26 Aug 2015 08:38:49 +0800 MIME-Version: 1.0 In-Reply-To: <55dc69b5.46268c0a.faa78.24eb@mx.google.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu Cc: akpm@linux-foundation.org, isimatu.yasuaki@jp.fujitsu.com, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, yanxiaofeng@inspur.com, fandd@inspur.com, Changsheng Liu First, thanks very much for your review, I will update codes according to your suggestion On 2015/8/25 21:12, Yasuaki Ishimatsu wrote: > On Thu, 20 Aug 2015 03:28:05 -0400 > Changsheng Liu wrote: > >> From: Changsheng Liu >> >> When memory is hot added, should_add_memory_movable() always returns 0 >> because the movable zone is empty, so the memory that was hot added will >> add to the normal zone even if we want to remove the memory. >> >> So we change should_add_memory_movable(): if the user config >> CONFIG_MOVABLE_NODE it will return 1 when the movable zone is empty. >> >> Reviewed-by: Andrew Morton >> Signed-off-by: Changsheng Liu >> Tested-by: Dongdong Fan >> --- >> mm/memory_hotplug.c | 3 +-- >> 1 files changed, 1 insertions(+), 2 deletions(-) >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 26fbba7..ff658f2 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1199,8 +1199,7 @@ static int should_add_memory_movable(int nid, u64 start, u64 size) >> struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; >> >> if (zone_is_empty(movable_zone)) >> - return 0; >> - >> + return IS_ENABLED(CONFIG_MOVABLE_NODE); >> if (movable_zone->zone_start_pfn <= start_pfn) >> return 1; > Currently, kernel allows to create ZONE_MOVABLE after ZONE_NORMAL as follows: > PFN low high > ---|-------------|-------------|--- > ZONE_NORMAL ZONE_MOVABLE > > But kernel does not allow to create ZONE_MOVABLE before ZONE_NORMAL as follows: > PFN low high > ---|-------------|-------------|--- > ZONE_MOVABLE ZONE_NORMAL > > Also, kernel does not allow to create ZONE_MOVABLE in ZOME_NORMAL as follows: > PFN low high > ---|-------------|-------------|-------------|--- > ZONE_NORMAL ZONE_MOVABLE ZONE_NORMAL > > So should_add_memory_movable() checks them. > > Accoring to your patch, when movable_zone is empty, the hot added memory is > always managed to ZONE_MOVABLE. It means that ZONE_MOVALBE will puts before/in > ZONE_NORMAL. > > You must prevent from creating ZONE_MOVABLE before/in ZONE_NORMAL. > > Thanks, > Yasuaki Ishimatsu > >> >> -- >> 1.7.1 >> >> -- >> 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 > . > -- 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