From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id BFE8E6B0055 for ; Wed, 15 Jul 2009 08:19:15 -0400 (EDT) Date: Wed, 15 Jul 2009 13:58:22 +0100 From: Mel Gorman 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 Sender: owner-linux-mm@kvack.org 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 List-ID: 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, 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