From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id DE2C56B004D for ; Thu, 12 Jan 2012 05:05:23 -0500 (EST) Date: Thu, 12 Jan 2012 11:05:21 +0100 From: Michal Hocko 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> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mel Gorman , Andrea Arcangeli 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: ---