From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754313AbYHTRJJ (ORCPT ); Wed, 20 Aug 2008 13:09:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751520AbYHTRI4 (ORCPT ); Wed, 20 Aug 2008 13:08:56 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:56668 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750766AbYHTRIz (ORCPT ); Wed, 20 Aug 2008 13:08:55 -0400 Subject: [BUG] Make setup_zone_migrate_reserve() aware of overlapping nodes From: Adam Litke To: linux-mm Cc: linux-kernel , Andrew Morton , nacc , mel@csn.ul.ie, apw , agl In-Reply-To: <1218837685.12953.11.camel@localhost.localdomain> References: <1218837685.12953.11.camel@localhost.localdomain> Content-Type: text/plain; charset=UTF-8 Organization: IBM Date: Wed, 20 Aug 2008 12:08:54 -0500 Message-Id: <1219252134.13885.25.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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): Node 0 Memory: 0x8000000-0x44000000 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. (Andrew: once the proper fix is agreed upon, this should also be a candidate for -stable.) setup_zone_migrate_reserve() should skip pageblocks in overlapping nodes. Signed-off-by: Adam Litke diff --git a/mm/page_alloc.c b/mm/page_alloc.c index af982f7..f297a9b 100644 --- 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; + if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); -- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center