Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754631AbZGOM6Y (ORCPT ); Wed, 15 Jul 2009 08:58:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754545AbZGOM6X (ORCPT ); Wed, 15 Jul 2009 08:58:23 -0400 Received: from gir.skynet.ie ([193.1.99.77]:38694 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754544AbZGOM6X (ORCPT ); Wed, 15 Jul 2009 08:58:23 -0400 Date: Wed, 15 Jul 2009 13:58:22 +0100 From: Mel Gorman To: Andrew Morton Cc: kosaki.motohiro@jp.fujitsu.com, Maxim Levitsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Lee Schermerhorn , Christoph Lameter , Pekka Enberg , Johannes Weiner , Jiri Slaby Subject: [PATCH] mm: Warn once when a page is freed with PG_mlocked set V2 Message-ID: <20090715125822.GB29749@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1972 Lines: 57 Changelog since V1 o Remove unnecessary branch When a page is freed with the PG_mlocked set, it is considered an unexpected but recoverable situation. A counter records how often this event happens but it is easy to miss that this event has occured at all. This patch warns once when PG_mlocked is set to prompt debuggers to check the counter to see how often it is happening. Signed-off-by: Mel Gorman --- mm/page_alloc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index caa9268..97c8ecf 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -495,8 +495,14 @@ static inline void free_page_mlock(struct page *page) static void free_page_mlock(struct page *page) { } #endif -static inline int free_pages_check(struct page *page) +static inline int free_pages_check(struct page *page, int wasMlocked) { + WARN_ONCE(wasMlocked, KERN_WARNING + "Page flag mlocked set for process %s at pfn:%05lx\n" + "page:%p flags:0x%lX\n", + current->comm, page_to_pfn(page), + page, page->flags|__PG_MLOCKED); + if (unlikely(page_mapcount(page) | (page->mapping != NULL) | (atomic_read(&page->_count) != 0) | @@ -562,7 +568,7 @@ static void __free_pages_ok(struct page *page, unsigned int order) kmemcheck_free_shadow(page, order); for (i = 0 ; i < (1 << order) ; ++i) - bad += free_pages_check(page + i); + bad += free_pages_check(page + i, wasMlocked); if (bad) return; @@ -1027,7 +1033,7 @@ static void free_hot_cold_page(struct page *page, int cold) if (PageAnon(page)) page->mapping = NULL; - if (free_pages_check(page)) + if (free_pages_check(page, wasMlocked)) return; if (!PageHighMem(page)) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/