From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755853AbbCSRNi (ORCPT ); Thu, 19 Mar 2015 13:13:38 -0400 Received: from mga11.intel.com ([192.55.52.93]:24386 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753573AbbCSRKr (ORCPT ); Thu, 19 Mar 2015 13:10:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,430,1422950400"; d="scan'208";a="694632350" From: "Kirill A. Shutemov" To: Andrew Morton , Andrea Arcangeli , Hugh Dickins Cc: Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: [PATCH 15/16] page-flags: look on head page if the flag is encoded in page->mapping Date: Thu, 19 Mar 2015 19:08:21 +0200 Message-Id: <1426784902-125149-16-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1426784902-125149-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1426784902-125149-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PageAnon() and PageKsm() look on lower bits of page->mapping to check if the page is Anon or KSM. page->mapping can be overloaded in tail pages. Let's always look on head page to avoid false-positives. Signed-off-by: Kirill A. Shutemov --- include/linux/page-flags.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 55a69c40e4ae..07fa2781df23 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -385,6 +385,7 @@ PAGEFLAG_FALSE(HWPoison) static inline int PageAnon(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; } @@ -397,6 +398,7 @@ static inline int PageAnon(struct page *page) */ static inline int PageKsm(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); } -- 2.1.4