From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753080Ab2FKKoZ (ORCPT ); Mon, 11 Jun 2012 06:44:25 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:53103 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751451Ab2FKKoX (ORCPT ); Mon, 11 Jun 2012 06:44:23 -0400 X-AuditID: cbfee61b-b7fcc6d000003a7a-23-4fd5cbfeed3c From: Bartlomiej Zolnierkiewicz To: Minchan Kim Subject: Re: [PATCH v10] mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks Date: Mon, 11 Jun 2012 12:43:14 +0200 User-Agent: KMail/1.13.2 (Linux/3.2.6; KDE/4.4.5; i686; ; ) Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , KOSAKI Motohiro , Dave Jones , Cong Wang , Markus Trippelsdorf , Mel Gorman , Rik van Riel , Marek Szyprowski , Kyungmin Park , Andrew Morton , Linus Torvalds References: <201206081046.32382.b.zolnierkie@samsung.com> <4FD54959.6060500@kernel.org> In-reply-to: <4FD54959.6060500@kernel.org> MIME-version: 1.0 Content-type: Text/Plain; charset=us-ascii Content-transfer-encoding: 7bit Message-id: <201206111243.14379.b.zolnierkie@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrJLMWRmVeSWpSXmKPExsVy+t9jQd1/p6/6G2w+pmJxedccNgdGj8+b 5AIYo7hsUlJzMstSi/TtErgyLky4wVJwnq/i6GPbBsbV3F2MnBwSAiYSyxoXMkHYYhIX7q1n 62Lk4hASmM4oceX2DCYIZzWTxOW1c8Cq2ASsJCa2r2IEsUUEVCT+PP0HZgsLxErsWLeHFcRm EVCVOHBlLTuILSpgLXH0wj1GkEHMAm+ZJdZ+fM/cxcgBNDVS4t+MfJAaTgEtif5PN8Hm8woI SvyYfI8FxGYGije/2cQIYctLbF7zlhmixlLidUszywRGgVlIWmYhaZmFpGUBI/MqRtHUguSC 4qT0XCO94sTc4tK8dL3k/NxNjOAAfCa9g3FVg8UhRgEORiUe3oalV/2FWBPLiitzDzFKcDAr ifBuqwAK8aYkVlalFuXHF5XmpBYfYpTmYFES522yvuAvJJCeWJKanZpakFoEk2Xi4JRqYCy4 xLW39/Mtk212nzZvEnroFvW5vGCp3pYtcV2/H6y+PslJ4SX3ezWD5ZlZU/0mT9+58+6fV+9a pDqXxV733Tvvbqn+PiPO07O09Fh11RcJ9ky4vqCP83CrVInvFWOJF/xXG+L0jE7ETNh3IMp/ UahFKmPOoYhOgbof/1X+nCrjt4+wzGIO363EUpyRaKjFXFScCADOkWj2PAIAAA== X-TM-AS-MML: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 11 June 2012 03:26:49 Minchan Kim wrote: > Hi Bartlomiej, > > On 06/08/2012 05:46 PM, Bartlomiej Zolnierkiewicz wrote: > > > > > Hi, > > > > This version is much simpler as it just uses __count_immobile_pages() > > instead of using its own open coded version and it integrates changes > > > That's a good idea. I don't have noticed that function is there. > When I look at the function, it has a problem, too. > Please, look at this. > > https://lkml.org/lkml/2012/6/10/180 > > If reviewer is okay that patch, I would like to resend your patch based on that. Ok, I would later merge all changes into v11 and rebase on top of your patch. > > from Minchan Kim (without page_count change as it doesn't seem correct > > > Why do you think so? > If it isn't correct, how can you prevent racing with THP page freeing? After seeing the explanation for the previous fix it is all clear now. > > and __count_immobile_pages() does the check in the standard way; if it > > still is a problem I think that removing 1st phase check altogether > > would be better instead of adding more locking complexity). > > > > The patch also adds compact_rescued_unmovable_blocks vmevent to vmstats > > to make it possible to easily check if the code is working in practice. > > > I think that part should be another patch. > > 1. Adding new vmstat would be arguable so it might interrupt this patch merging. Why would it be arguable? It seems non-intrusive and obvious to me. > 2. New vmstat adding is just for this patch is effective or not in real practice > so if we prove it in future, let's revert the vmstat. Separating it would make it > easily. I would like to add this vmstat permanently, not only for the testing period.. Best regards, -- Bartlomiej Zolnierkiewicz Samsung Poland R&D Center