From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id C5D036B004F for ; Tue, 23 Jun 2009 07:04:09 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n5NB4CSW032595 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 23 Jun 2009 20:04:13 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id C76E845DD7C for ; Tue, 23 Jun 2009 20:04:12 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id A236445DE51 for ; Tue, 23 Jun 2009 20:04:12 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 7D273E08008 for ; Tue, 23 Jun 2009 20:04:12 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 20EB4E0800E for ; Tue, 23 Jun 2009 20:04:12 +0900 (JST) From: KOSAKI Motohiro Subject: Re: BUG: Bad page state [was: Strange oopses in 2.6.30] In-Reply-To: <20090622091626.GA3981@csn.ul.ie> References: <20090622113652.21E7.A69D9226@jp.fujitsu.com> <20090622091626.GA3981@csn.ul.ie> Message-Id: <20090623200147.2236.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 23 Jun 2009 20:04:11 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: kosaki.motohiro@jp.fujitsu.com, Jiri Slaby , Maxim Levitsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Lee Schermerhorn , Christoph Lameter , Pekka Enberg , Hugh Dickins , Johannes Weiner , Rik van Riel List-ID: > On Mon, Jun 22, 2009 at 11:39:53AM +0900, KOSAKI Motohiro wrote: > > (cc to Mel and some reviewer) > > > > > Flags are: > > > 0000000000400000 -- __PG_MLOCKED > > > 800000000050000c -- my page flags > > > 3650000c -- Maxim's page flags > > > 0000000000693ce1 -- my PAGE_FLAGS_CHECK_AT_FREE > > > > I guess commit da456f14d (page allocator: do not disable interrupts in > > free_page_mlock()) is a bit wrong. > > > > current code is: > > ------------------------------------------------------------- > > static void free_hot_cold_page(struct page *page, int cold) > > { > > (snip) > > int clearMlocked = PageMlocked(page); > > (snip) > > if (free_pages_check(page)) > > return; > > (snip) > > local_irq_save(flags); > > if (unlikely(clearMlocked)) > > free_page_mlock(page); > > ------------------------------------------------------------- > > > > Oh well, we remove PG_Mlocked *after* free_pages_check(). > > Then, it makes false-positive warning. > > > > Sorry, my review was also wrong. I think reverting this patch is better ;) > > > > I think a revert is way overkill. The intention of the patch is sound - > reducing the number of times interrupts are disabled. Having pages > with the PG_locked bit is now somewhat of an expected situation. I'd > prefer to go with either > > 1. Unconditionally clearing the bit with TestClearPageLocked as the > patch already posted does > 2. Removing PG_locked from the free_pages_check() > 3. Unlocking the pages as we go when an mlocked VMA is being torn town > > The patch that addresses 1 seemed ok to me. What do you think? Yes, I've overlooked Hanns's patch. I think that is good patch. Thansk folks. -- 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