From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753305AbcDAITa (ORCPT ); Fri, 1 Apr 2016 04:19:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:37632 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751337AbcDAIT1 (ORCPT ); Fri, 1 Apr 2016 04:19:27 -0400 Subject: Re: [PATCH v2 5/5] power: add zone range overlapping check To: js1304@gmail.com, Andrew Morton References: <1459476406-28418-1-git-send-email-iamjoonsoo.kim@lge.com> <1459476406-28418-6-git-send-email-iamjoonsoo.kim@lge.com> Cc: Rik van Riel , Johannes Weiner , Mel Gorman , Laura Abbott , Minchan Kim , Marek Szyprowski , Michal Nazarewicz , "Aneesh Kumar K.V" , "Rafael J. Wysocki" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim From: Vlastimil Babka Message-ID: <56FE2F11.2090406@suse.cz> Date: Fri, 1 Apr 2016 10:19:29 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <1459476406-28418-6-git-send-email-iamjoonsoo.kim@lge.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1.4.2016 4:06, js1304@gmail.com wrote: > From: Joonsoo Kim > > There is a system that node's pfn are overlapped like as following. > > -----pfn--------> > N0 N1 N2 N0 N1 N2 > > Therefore, we need to care this overlapping when iterating pfn range. > > mark_free_pages() iterates requested zone's pfn range and unset > all range's bitmap first. And then it marks freepages in a zone > to the bitmap. If there is an overlapping zone, above unset could > clear previous marked bit and reference to this bitmap in the future > will cause the problem. To prevent it, this patch adds a zone check > in mark_free_pages(). > > Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka > --- > mm/page_alloc.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 0cfee62..437a934 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2156,6 +2156,10 @@ void mark_free_pages(struct zone *zone) > for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) > if (pfn_valid(pfn)) { > page = pfn_to_page(pfn); > + > + if (page_zone(page) != zone) > + continue; > + > if (!swsusp_page_is_forbidden(page)) > swsusp_unset_page_free(page); > } >