From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e6.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m7KIEbdZ012597 for ; Wed, 20 Aug 2008 14:14:37 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m7KIBr0o229930 for ; Wed, 20 Aug 2008 14:11:53 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m7KIBrJ9006872 for ; Wed, 20 Aug 2008 14:11:53 -0400 Subject: Re: [BUG] Make setup_zone_migrate_reserve() aware of overlapping nodes From: Dave Hansen In-Reply-To: <1219252134.13885.25.camel@localhost.localdomain> References: <1218837685.12953.11.camel@localhost.localdomain> <1219252134.13885.25.camel@localhost.localdomain> Content-Type: text/plain; charset=UTF-8 Date: Wed, 20 Aug 2008 11:11:51 -0700 Message-Id: <1219255911.8960.41.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org Return-Path: To: Adam Litke Cc: linux-mm , linux-kernel , Andrew Morton , nacc , mel@csn.ul.ie, apw , agl List-ID: On Wed, 2008-08-20 at 12:08 -0500, Adam Litke wrote: > I have gotten to the root cause of the hugetlb badness I reported back > on August 15th. My system has the following memory topology (note the > overlapping node): > > i>>?Node 0 Memory: 0x8000000-0x44000000 > i>>?Node 1 Memory: 0x0-0x8000000 0x44000000-0x80000000 > > setup_zone_migrate_reserve() scans the address range 0x0-0x8000000 > looking for a pageblock to move onto the MIGRATE_RESERVE list. Finding > no candidates, it happily continues the scan into 0x8000000-0x44000000. > When a pageblock is found, the pages are moved to the MIGRATE_RESERVE > list on the wrong zone. Oops. This eventually gets down into move_freepages() via: ->setup_zone_migrate_reserve() ->move_freepages_block() ->move_freepages() right? It looks like there have been bugs in this area before in move_freepages(). Should there be a more stringent check in *there*? Maybe a warning? > i>>? > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2512,6 +2512,10 @@ static void setup_zone_migrate_reserve(struct > zone *zone) > pageblock_order; > > for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { > + /* Watch out for overlapping nodes */ > + if (!early_pfn_in_nid(pfn, zone->node)) > + continue; zone->node doesn't exist on !CONFIG_NUMA. :( You probably want: if (!early_pfn_in_nid(pfn, zone_to_nid(zone))) continue; Are you sure you need the "early_" variant here? We're not using early_pfn_valid() right below it. I guess you could also use: if (!page_to_nid(page) != zone_to_nid(zone)) continue; -- Dave -- 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