From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) by kanga.kvack.org (Postfix) with ESMTP id CC4586B006E for ; Tue, 9 Dec 2014 02:53:02 -0500 (EST) Received: by mail-pa0-f43.google.com with SMTP id kx10so75873pab.2 for ; Mon, 08 Dec 2014 23:53:02 -0800 (PST) Received: from mailout3.samsung.com (mailout3.samsung.com. [203.254.224.33]) by mx.google.com with ESMTPS id du2si559129pdb.156.2014.12.08.23.52.59 for (version=TLSv1 cipher=RC4-MD5 bits=128/128); Mon, 08 Dec 2014 23:53:00 -0800 (PST) Received: from epcpsbgm1.samsung.com (epcpsbgm1 [203.254.230.26]) by mailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NGB00GWY1W9Z220@mailout3.samsung.com> for linux-mm@kvack.org; Tue, 09 Dec 2014 16:52:58 +0900 (KST) From: Weijie Yang Subject: [PATCH 2/3] mm: page_isolation: remove unnecessary freepage_migratetype check for unused page Date: Tue, 09 Dec 2014 15:51:49 +0800 Message-id: <000201d01385$25a6c950$70f45bf0$%yang@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 7bit Content-language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: iamjoonsoo.kim@lge.com Cc: 'Andrew Morton' , mgorman@suse.de, 'Rik van Riel' , vbabka@suse.cz, 'Johannes Weiner' , 'Minchan Kim' , 'Weijie Yang' , linux-kernel@vger.kernel.org, linux-mm@kvack.org when we test the pages in a range is free or not, there is a little chance we encounter some page which is not in buddy but page_count is 0. That means that page could be in the page-freeing path but not in the buddy freelist, such as in pcplist or wait for the zone->lock which the tester is holding. Back to the freepage_migratetype, we use it for a cached value for decide which free-list the page go when freeing page. If the pageblock is isolated the page will go to free-list[MIGRATE_ISOLATE] even if the cached type is not MIGRATE_ISOLATE, the commit ad53f92e(fix incorrect isolation behavior by rechecking migratetype) patch series have ensure this. So the freepage_migratetype check for page_count==0 page in __test_page_isolated_in_pageblock() is meaningless. This patch removes the unnecessary freepage_migratetype check. Signed-off-by: Weijie Yang --- mm/page_isolation.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 6e5174d..f7c9183 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -223,8 +223,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, page = pfn_to_page(pfn); if (PageBuddy(page)) pfn += 1 << page_order(page); - else if (page_count(page) == 0 && - get_freepage_migratetype(page) == MIGRATE_ISOLATE) + else if (page_count(page) == 0) pfn += 1; else if (skip_hwpoisoned_pages && PageHWPoison(page)) { /* -- 1.7.10.4 -- 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