From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032353Ab2I1UZl (ORCPT ); Fri, 28 Sep 2012 16:25:41 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:48962 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032337Ab2I1UZe (ORCPT ); Fri, 28 Sep 2012 16:25:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Haifeng Li , Gavin Shan , Michal Hocko , KyongHo Cho , Mel Gorman , Minchan Kim , Johannes Weiner , Andrew Morton , Linus Torvalds Subject: [ 076/218] mm/page_alloc: fix the page address of higher pages buddy calculation Date: Fri, 28 Sep 2012 13:14:53 -0700 Message-Id: <20120928201510.291909574@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.1.428.g652398a In-Reply-To: <20120928201501.208384923@linuxfoundation.org> References: <20120928201501.208384923@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Haifeng commit 0ba8f2d59304dfe69b59c034de723ad80f7ab9ac upstream. The heuristic method for buddy has been introduced since commit 43506fad21ca ("mm/page_alloc.c: simplify calculation of combined index of adjacent buddy lists"). But the page address of higher page's buddy was wrongly calculated, which will lead page_is_buddy to fail for ever. IOW, the heuristic method would be disabled with the wrong page address of higher page's buddy. Calculating the page address of higher page's buddy should be based higher_page with the offset between index of higher page and index of higher page's buddy. Signed-off-by: Haifeng Li Signed-off-by: Gavin Shan Reviewed-by: Michal Hocko Cc: KyongHo Cho Cc: Mel Gorman Cc: Minchan Kim Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -579,7 +579,7 @@ static inline void __free_one_page(struc combined_idx = buddy_idx & page_idx; higher_page = page + (combined_idx - page_idx); buddy_idx = __find_buddy_index(combined_idx, order + 1); - higher_buddy = page + (buddy_idx - combined_idx); + higher_buddy = higher_page + (buddy_idx - combined_idx); if (page_is_buddy(higher_page, higher_buddy, order + 1)) { list_add_tail(&page->lru, &zone->free_area[order].free_list[migratetype]);