From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756298AbaCLG6M (ORCPT ); Wed, 12 Mar 2014 02:58:12 -0400 Received: from lgeamrelo04.lge.com ([156.147.1.127]:63419 "EHLO lgeamrelo04.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755425AbaCLG6L (ORCPT ); Wed, 12 Mar 2014 02:58:11 -0400 X-Original-SENDERIP: 10.186.119.203 X-Original-MAILFROM: jungsoo.son@lge.com From: Jungsoo Son To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jungsoo Son , Minchan Kim , Joonsoo Kim Subject: [PATCH] page owners: correct page->order when to free page Date: Wed, 12 Mar 2014 15:58:06 +0900 Message-Id: <1394607486-31493-1-git-send-email-jungsoo.son@lge.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When I use PAGE_OWNER in mmotm tree, I found a problem that mismatches the number of allocated pages. When I investigate, the problem is that set_page_order is called for only a head page if freed page is merged to a higher order page in the buddy allocator so tail pages of the higher order page couldn't be reset to page->order = -1. It means when we do 'cat /proc/page-owner', it could show wrong information. So page->order should be set to -1 for all the tail pages as well as the first page before buddy allocator merges them. This patch is for clearing page->order of all the tail pages in free_pages_prepare() when to free page. Signed-off-by: Jungsoo Son Cc: Minchan Kim Cc: Joonsoo Kim --- mm/page_alloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index dfbc967..9b946f0 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -741,6 +741,13 @@ static bool free_pages_prepare(struct page *page, unsigned int order) if (bad) return false; +#ifdef CONFIG_PAGE_OWNER + for (i = 0; i < (1 << order); i++) { + struct page *p = (page + i); + p->order = -1; + } +#endif + if (!PageHighMem(page)) { debug_check_no_locks_freed(page_address(page), PAGE_SIZE << order); -- 1.7.9.5