From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592Ab2ALKF0 (ORCPT ); Thu, 12 Jan 2012 05:05:26 -0500 Received: from cantor2.suse.de ([195.135.220.15]:50315 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751153Ab2ALKFX (ORCPT ); Thu, 12 Jan 2012 05:05:23 -0500 Date: Thu, 12 Jan 2012 11:05:21 +0100 From: Michal Hocko To: KAMEZAWA Hiroyuki Cc: David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mel Gorman , Andrea Arcangeli Subject: [PATCH] mm: __count_immobile_pages make sure the node is online Message-ID: <20120112100521.GD1042@tiehlicka.suse.cz> References: <1326213022-11761-1-git-send-email-mhocko@suse.cz> <20120111084802.GA16466@tiehlicka.suse.cz> <20120112111702.3b7f2fa2.kamezawa.hiroyu@jp.fujitsu.com> <20120112082722.GB1042@tiehlicka.suse.cz> <20120112173536.db529713.kamezawa.hiroyu@jp.fujitsu.com> <20120112092314.GC1042@tiehlicka.suse.cz> <20120112183323.1bb62f4d.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120112183323.1bb62f4d.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 12-01-12 18:33:23, KAMEZAWA Hiroyuki wrote: [...] > > From 04f74e6f0ebf28f61650d63f8884e8855fb21b55 Mon Sep 17 00:00:00 2001 > > From: Michal Hocko > > Date: Thu, 12 Jan 2012 10:19:04 +0100 > > Subject: [PATCH] mm: __count_immobile_pages make sure the node is online > > > > page_zone requires to have an online node otherwise we are accessing > > NULL NODE_DATA. This is not an issue at the moment because node_zones > > are located at the structure beginning but this might change in the > > future so better be careful about that. > > > > Signed-off-by: Michal Hocko > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > mm/page_alloc.c | 11 +++++++++-- > > 1 files changed, 9 insertions(+), 2 deletions(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 485be89..c6fb8ea 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -5607,14 +5607,21 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count) > > > > bool is_pageblock_removable_nolock(struct page *page) > > { > > - struct zone *zone = page_zone(page); > > - unsigned long pfn = page_to_pfn(page); > > + struct zone *zone; > > + unsigned long pfn; > > > > /* > > * We have to be careful here because we are iterating over memory > > * sections which are not zone aware so we might end up outside of > > * the zone but still within the section. > > + * We have to take care about the node as well. If the node is offline > > + * its NODE_DATA will be NULL - see page_zone. > > */ > > + if (!node_online(page_to_nid(page))) > > + return false; > > + > > + zone = page_zone(page); > > + pfn = page_to_pfn(page); > > if (!zone || zone->zone_start_pfn > pfn || > > zone->zone_start_pfn + zone->spanned_pages <= pfn) > > return false; > > !zone check can be removed because of node_online() check. Yes you are right. Fixed bellow: --- >>From 39de8df13532150fc4518dad0cb3f6fd88745b8a Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 12 Jan 2012 10:19:04 +0100 Subject: [PATCH] mm: __count_immobile_pages make sure the node is online page_zone requires to have an online node otherwise we are accessing NULL NODE_DATA. This is not an issue at the moment because node_zones are located at the structure beginning but this might change in the future so better be careful about that. Signed-off-by: Michal Hocko Signed-off-by: KAMEZAWA Hiroyuki --- mm/page_alloc.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 485be89..b09e8c2 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5607,15 +5607,22 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count) bool is_pageblock_removable_nolock(struct page *page) { - struct zone *zone = page_zone(page); - unsigned long pfn = page_to_pfn(page); + struct zone *zone; + unsigned long pfn; /* * We have to be careful here because we are iterating over memory * sections which are not zone aware so we might end up outside of * the zone but still within the section. + * We have to take care about the node as well. If the node is offline + * its NODE_DATA will be NULL - see page_zone. */ - if (!zone || zone->zone_start_pfn > pfn || + if (!node_online(page_to_nid(page))) + return false; + + zone = page_zone(page); + pfn = page_to_pfn(page); + if (zone->zone_start_pfn > pfn || zone->zone_start_pfn + zone->spanned_pages <= pfn) return false; -- 1.7.7.3 -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic