From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933237AbbHZAi7 (ORCPT ); Tue, 25 Aug 2015 20:38:59 -0400 Received: from bgp253.corp-email.cn ([112.65.243.253]:2187 "EHLO bgp253.corp-email.cn" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932084AbbHZAi6 (ORCPT ); Tue, 25 Aug 2015 20:38:58 -0400 Subject: Re: [PATCH V2] mm:memory hot-add: memory can not been added to movable zone To: Yasuaki Ishimatsu References: <1440055685-6083-1-git-send-email-liuchangsheng@inspur.com> <55dc69b5.46268c0a.faa78.24eb@mx.google.com> CC: , , , , , , , Changsheng Liu From: Changsheng Liu Message-ID: <55DD0A99.5080803@inspur.com> Date: Wed, 26 Aug 2015 08:38:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 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 X-Originating-IP: [10.165.23.10] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > . >