Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751184AbdFAMcs (ORCPT ); Thu, 1 Jun 2017 08:32:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:37196 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751090AbdFAMcq (ORCPT ); Thu, 1 Jun 2017 08:32:46 -0400 Subject: Re: [PATCH 1/2] mm, memory_hotplug: fix MMOP_ONLINE_KEEP behavior To: Michal Hocko , Andrew Morton Cc: linux-mm@kvack.org, Mel Gorman , Andrea Arcangeli , Jerome Glisse , Reza Arbab , Yasuaki Ishimatsu , qiuxishi@huawei.com, Kani Toshimitsu , slaoub@gmail.com, Joonsoo Kim , Andi Kleen , David Rientjes , Daniel Kiper , Igor Mammedov , Vitaly Kuznetsov , Heiko Carstens , LKML , Michal Hocko References: <20170601083746.4924-1-mhocko@kernel.org> <20170601083746.4924-2-mhocko@kernel.org> From: Vlastimil Babka Message-ID: Date: Thu, 1 Jun 2017 14:32:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <20170601083746.4924-2-mhocko@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2562 Lines: 67 On 06/01/2017 10:37 AM, Michal Hocko wrote: > From: Michal Hocko > > Heiko Carstens has noticed that the MMOP_ONLINE_KEEP is broken currently > $ grep . memory3?/valid_zones > memory34/valid_zones:Normal Movable > memory35/valid_zones:Normal Movable > memory36/valid_zones:Normal Movable > memory37/valid_zones:Normal Movable > > $ echo online_movable > memory34/state > $ grep . memory3?/valid_zones > memory34/valid_zones:Movable > memory35/valid_zones:Movable > memory36/valid_zones:Movable > memory37/valid_zones:Movable > > $ echo online > memory36/state > $ grep . memory3?/valid_zones > memory34/valid_zones:Movable > memory36/valid_zones:Normal > memory37/valid_zones:Movable > > so we have effectivelly punched a hole into the movable zone. The > problem is that move_pfn_range() check for MMOP_ONLINE_KEEP is wrong. > It only checks whether the given range is already part of the movable > zone which is not the case here as only memory34 is in the zone. Fix > this by using allow_online_pfn_range(..., MMOP_ONLINE_KERNEL) if that > is false then we can be sure that movable onlining is the right thing to > do. > > Reported-by: Heiko Carstens > Tested-by: Heiko Carstens > Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online" Just fold it there before sending to Linus, right? > Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka > --- > mm/memory_hotplug.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 0a895df2397e..b3895fd609f4 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -950,11 +950,12 @@ static struct zone * __meminit move_pfn_range(int online_type, int nid, > if (online_type == MMOP_ONLINE_KEEP) { > struct zone *movable_zone = &pgdat->node_zones[ZONE_MOVABLE]; > /* > - * MMOP_ONLINE_KEEP inherits the current zone which is > - * ZONE_NORMAL by default but we might be within ZONE_MOVABLE > - * already. > + * MMOP_ONLINE_KEEP defaults to MMOP_ONLINE_KERNEL but use > + * movable zone if that is not possible (e.g. we are within > + * or past the existing movable zone) > */ > - if (zone_intersects(movable_zone, start_pfn, nr_pages)) > + if (!allow_online_pfn_range(nid, start_pfn, nr_pages, > + MMOP_ONLINE_KERNEL)) > zone = movable_zone; > } else if (online_type == MMOP_ONLINE_MOVABLE) { > zone = &pgdat->node_zones[ZONE_MOVABLE]; >