From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx103.postini.com [74.125.245.103]) by kanga.kvack.org (Postfix) with SMTP id 6D1A06B004D for ; Mon, 30 Jan 2012 08:25:47 -0500 (EST) Date: Mon, 30 Jan 2012 13:25:43 +0000 From: Mel Gorman Subject: Re: [PATCH 03/15] mm: compaction: introduce isolate_migratepages_range(). Message-ID: <20120130132543.GP25268@csn.ul.ie> References: <1327568457-27734-1-git-send-email-m.szyprowski@samsung.com> <1327568457-27734-4-git-send-email-m.szyprowski@samsung.com> <20120130112428.GF25268@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Michal Nazarewicz Cc: Marek Szyprowski , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org, Kyungmin Park , Russell King , Andrew Morton , KAMEZAWA Hiroyuki , Daniel Walker , Arnd Bergmann , Jesse Barker , Jonathan Corbet , Shariq Hasnain , Chunsang Jeong , Dave Hansen , Benjamin Gaignard On Mon, Jan 30, 2012 at 01:42:50PM +0100, Michal Nazarewicz wrote: > >On Thu, Jan 26, 2012 at 10:00:45AM +0100, Marek Szyprowski wrote: > >>From: Michal Nazarewicz > >>@@ -313,7 +316,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, > >> } else if (!locked) > >> spin_lock_irq(&zone->lru_lock); > >> > >>- if (!pfn_valid_within(low_pfn)) > >>+ if (!pfn_valid(low_pfn)) > >> continue; > >> nr_scanned++; > >> > > On Mon, 30 Jan 2012 12:24:28 +0100, Mel Gorman wrote: > >This chunk looks unrelated to the rest of the patch. > > > >I think what you are doing is patching around a bug that CMA exposed > >which is very similar to the bug report at > >http://www.spinics.net/lists/linux-mm/msg29260.html . Is this true? > > > >If so, I posted a fix that only calls pfn_valid() when necessary. Can > >you check if that works for you and if so, drop this hunk please? If > >the patch does not work for you, then this hunk still needs to be > >in a separate patch and handled separately as it would also be a fix > >for -stable. > > I'll actually never encountered this bug myself and CMA is unlikely to > expose it, since it always operates on continuous memory regions with > no holes. > > I've made this change because looking at the code it seemed like this > may cause problems in some cases. The crash that you linked to looks > like the kind of problem I was thinking about. > > I'll drop this hunk and let you resolve this independently of CMA. > Ok, thanks. -- Mel Gorman SUSE Labs -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org