From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753514AbaCMPFR (ORCPT ); Thu, 13 Mar 2014 11:05:17 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41189 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751335AbaCMPFP (ORCPT ); Thu, 13 Mar 2014 11:05:15 -0400 Date: Thu, 13 Mar 2014 15:05:12 +0000 From: Mel Gorman To: Bartlomiej Zolnierkiewicz Cc: Hugh Dickins , Marek Szyprowski , Yong-Taek Lee , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH v2] mm/page_alloc: fix freeing of MIGRATE_RESERVE migratetype pages Message-ID: <20140313150512.GR10663@suse.de> References: <42197912.c6v2hLDCey@amdc1032> <20140313142540.GQ10663@suse.de> <3661570.lSOEkVGv4G@amdc1032> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <3661570.lSOEkVGv4G@amdc1032> 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, Mar 13, 2014 at 03:37:46PM +0100, Bartlomiej Zolnierkiewicz wrote: > On Thursday, March 13, 2014 02:25:40 PM Mel Gorman wrote: > > On Fri, Feb 14, 2014 at 07:34:17PM +0100, Bartlomiej Zolnierkiewicz wrote: > > > Pages allocated from MIGRATE_RESERVE migratetype pageblocks > > > are not freed back to MIGRATE_RESERVE migratetype free > > > lists in free_pcppages_bulk()->__free_one_page() if we got > > > to free_pcppages_bulk() through drain_[zone_]pages(). > > > The freeing through free_hot_cold_page() is okay because > > > freepage migratetype is set to pageblock migratetype before > > > calling free_pcppages_bulk(). If pages of MIGRATE_RESERVE > > > migratetype end up on the free lists of other migratetype > > > whole Reserved pageblock may be later changed to the other > > > migratetype in __rmqueue_fallback() and it will be never > > > changed back to be a Reserved pageblock. Fix the issue by > > > preserving freepage migratetype as a pageblock migratetype > > > (instead of overriding it to the requested migratetype) > > > for MIGRATE_RESERVE migratetype pages in rmqueue_bulk(). > > > > > > The problem was introduced in v2.6.31 by commit ed0ae21 > > > ("page allocator: do not call get_pageblock_migratetype() > > > more than necessary"). > > > > > > Signed-off-by: Bartlomiej Zolnierkiewicz > > > Reported-by: Yong-Taek Lee > > > Cc: Marek Szyprowski > > > Cc: Mel Gorman > > > Cc: Hugh Dickins > > > > It's a pity about the unconditional pageblock lookup in that path but I > > didn't see a better way around it so > > > > Acked-by: Mel Gorman > > Thanks but does that mean that v3 should be abandoned: > > https://lkml.org/lkml/2014/3/6/365 > Bah, no. v3 looks better. I was going through the vast pile of mail marked unread and thought it must be the latest version if it was still "new" and didn't search linux-mm. I was obviously thinking more clearly when I saw v2 the first time. Sorry for the confusion. -- Mel Gorman SUSE Labs