From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e35.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m7KJtsYB015277 for ; Wed, 20 Aug 2008 15:55:54 -0400 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m7KJtpPd215496 for ; Wed, 20 Aug 2008 13:55:53 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m7KJtpLn032690 for ; Wed, 20 Aug 2008 13:55:51 -0600 Subject: [BUG] [PATCH v2] Make setup_zone_migrate_reserve() aware of overlapping nodes From: Adam Litke In-Reply-To: <1219255911.8960.41.camel@nimitz> References: <1218837685.12953.11.camel@localhost.localdomain> <1219252134.13885.25.camel@localhost.localdomain> <1219255911.8960.41.camel@nimitz> Content-Type: text/plain Date: Wed, 20 Aug 2008 14:55:52 -0500 Message-Id: <1219262152.13885.27.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: linux-mm , linux-kernel , Andrew Morton , nacc , mel@csn.ul.ie, apw , agl List-ID: 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..feb7916 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -694,6 +694,9 @@ static int move_freepages(struct zone *zone, #endif for (page = start_page; page <= end_page;) { + /* Make sure we are not inadvertently changing nodes */ + VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone)); + if (!pfn_valid_within(page_to_pfn(page))) { page++; continue; @@ -2516,6 +2519,10 @@ static void setup_zone_migrate_reserve(struct zone *zone) continue; page = pfn_to_page(pfn); + /* Watch out for overlapping nodes */ + if (page_to_nid(page) != zone_to_nid(zone)) + continue; + /* Blocks with reserved pages will never free, skip them. */ if (PageReserved(page)) continue; -- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center -- 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