From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id BCFDC6B004D for ; Tue, 30 Jun 2009 11:10:48 -0400 (EDT) Date: Tue, 30 Jun 2009 16:11:03 +0100 From: Mel Gorman Subject: Re: BUG: Bad page state [was: Strange oopses in 2.6.30] Message-ID: <20090630151103.GF17561@csn.ul.ie> References: <20090623200846.223C.A69D9226@jp.fujitsu.com> <20090629084114.GA28597@csn.ul.ie> <20090630092847.A730.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090630092847.A730.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Lee Schermerhorn , Jiri Slaby , Maxim Levitsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Christoph Lameter , Pekka Enberg , Rik van Riel List-ID: On Tue, Jun 30, 2009 at 09:31:04AM +0900, KOSAKI Motohiro wrote: > Hi > > Thank you new version. > > > ==== CUT HERE ==== > > mm: Warn once when a page is freed with PG_mlocked set > > > > 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 | 16 ++++++++++++---- > > 1 file changed, 12 insertions(+), 4 deletions(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 5d714f8..519ea6e 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -495,8 +495,16 @@ 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) > > +{ > > + if (unlikely(wasMlocked)) { > > + WARN_ONCE(1, KERN_WARNING > > + "Page flag mlocked set for process %s at pfn:%05lx\n" > > + "page:%p flags:0x%lX\n", > > 0x%lX is a bit redundunt. > %lX insert "0x" string by itself, I think. > It does not automatically insert the 0x for me and I just did a quick test there. Can you double check please? > > > + 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 +570,7 @@ 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 +1035,7 @@ 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)) { > > Other part looks fine. thanks. > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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