From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f49.google.com (mail-pa0-f49.google.com [209.85.220.49]) by kanga.kvack.org (Postfix) with ESMTP id B73366B0031 for ; Thu, 9 Jan 2014 02:04:33 -0500 (EST) Received: by mail-pa0-f49.google.com with SMTP id kx10so2916759pab.36 for ; Wed, 08 Jan 2014 23:04:33 -0800 (PST) Received: from LGEMRELSE7Q.lge.com (LGEMRELSE7Q.lge.com. [156.147.1.151]) by mx.google.com with ESMTP id eb3si2955614pbd.257.2014.01.08.23.04.30 for ; Wed, 08 Jan 2014 23:04:32 -0800 (PST) From: Joonsoo Kim Subject: [PATCH 0/7] improve robustness on handling migratetype Date: Thu, 9 Jan 2014 16:04:40 +0900 Message-Id: <1389251087-10224-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A. Shutemov" , Rik van Riel , Jiang Liu , Mel Gorman , Cody P Schafer , Johannes Weiner , Michal Hocko , Minchan Kim , Michal Nazarewicz , Andi Kleen , Wei Yongjun , Tang Chen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim , Joonsoo Kim Hello, I found some weaknesses on handling migratetype during code review and testing CMA. First, we don't have any synchronization method on get/set pageblock migratetype. When we change migratetype, we hold the zone lock. So writer-writer race doesn't exist. But while someone changes migratetype, others can get migratetype. This may introduce totally unintended value as migratetype. Although I haven't heard of any problem report about that, it is better to protect properly. Second, (get/set)_freepage_migrate isn't used properly. I guess that it would be introduced for per cpu page(pcp) performance, but, it is also used by memory isolation, now. For that case, the information isn't enough to use, so we need to fix it. Third, there is the problem on buddy allocator. It doesn't consider migratetype when merging buddy, so pages from cma or isolate region can be moved to other migratetype freelist. It makes CMA failed over and over. To prevent it, the buddy allocator should consider migratetype if CMA/ISOLATE is enabled. This patchset is aimed at fixing these problems and based on v3.13-rc7. Thanks. Joonsoo Kim (7): mm/page_alloc: synchronize get/set pageblock mm/cma: fix cma free page accounting mm/page_alloc: move set_freepage_migratetype() to better place mm/isolation: remove invalid check condition mm/page_alloc: separate interface to set/get migratetype of freepage mm/page_alloc: store freelist migratetype to the page on buddy properly mm/page_alloc: don't merge MIGRATE_(CMA|ISOLATE) pages on buddy include/linux/mm.h | 35 +++++++++++++++++++++--- include/linux/mmzone.h | 2 ++ include/linux/page-isolation.h | 1 - mm/page_alloc.c | 59 ++++++++++++++++++++++++++-------------- mm/page_isolation.c | 5 +--- 5 files changed, 73 insertions(+), 29 deletions(-) -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org