From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757092Ab2I1Ihd (ORCPT ); Fri, 28 Sep 2012 04:37:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:51871 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757034Ab2I1Ih3 (ORCPT ); Fri, 28 Sep 2012 04:37:29 -0400 Date: Fri, 28 Sep 2012 09:37:22 +0100 From: Mel Gorman To: Minchan Kim Cc: Andrew Morton , Thierry Reding , Marek Szyprowski , Michal Nazarewicz , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Bartlomiej Zolnierkiewicz , Kyungmin Park , Mark Brown , Peter Ujfalusi Subject: Re: CMA broken in next-20120926 Message-ID: <20120928083722.GM3429@suse.de> References: <20120927112911.GA25959@avionic-0098.mockup.avionic-design.de> <20120927151159.4427fc8f.akpm@linux-foundation.org> <20120928054330.GA27594@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120928054330.GA27594@bbox> 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 > I hope this patch fixes the bug. If this patch fixes the problem > but has some problem about description or someone has better idea, > feel free to modify and resend to akpm, Please. > A full revert is overkill. Can the following patch be tested as a potential replacement please? ---8<--- mm: compaction: Iron out isolate_freepages_block() and isolate_freepages_range() -fix1 CMA is reported to be broken in next-20120926. Minchan Kim pointed out that this was due to nr_scanned != total_isolated in the case of CMA because PageBuddy pages are one scan but many isolations in CMA. This patch should address the problem. This patch is a fix for mm-compaction-acquire-the-zone-lock-as-late-as-possible-fix-2.patch Signed-off-by: Mel Gorman --- mm/compaction.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 8250b69..d6e260a 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -282,6 +282,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, { int nr_scanned = 0, total_isolated = 0; struct page *cursor, *valid_page = NULL; + unsigned long nr_strict_required = end_pfn - blockpfn; unsigned long flags; bool locked = false; @@ -343,10 +344,10 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, /* * If strict isolation is requested by CMA then check that all the - * pages scanned were isolated. If there were any failures, 0 is + * pages requested were isolated. If there were any failures, 0 is * returned and CMA will fail. */ - if (strict && nr_scanned != total_isolated) + if (strict && nr_strict_required != total_isolated) total_isolated = 0; if (locked)