From: Adam Litke <agl@us.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
nacc <nacc@linux.vnet.ibm.com>,
mel@csn.ul.ie, apw <apw@shadowen.org>,
agl <agl@linux.vnet.ibm.com>
Subject: [BUG] [PATCH v2] Make setup_zone_migrate_reserve() aware of overlapping nodes
Date: Wed, 20 Aug 2008 14:55:52 -0500 [thread overview]
Message-ID: <1219262152.13885.27.camel@localhost.localdomain> (raw)
In-Reply-To: <1219255911.8960.41.camel@nimitz>
Changes since V1
- Fix build for !NUMA
- Add VM_BUG_ON() to catch this problem at the source
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 <agl@us.ibm.com>
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
next prev parent reply other threads:[~2008-08-20 19:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-15 22:01 [BUG] __GFP_THISNODE is not always honored Adam Litke
2008-08-18 10:59 ` Mel Gorman
2008-08-18 18:16 ` Adam Litke
2008-08-18 19:57 ` Mel Gorman
2008-08-18 19:14 ` Christoph Lameter
2008-08-18 19:21 ` Christoph Lameter
2008-08-18 19:52 ` Mel Gorman
2008-08-20 17:08 ` [BUG] Make setup_zone_migrate_reserve() aware of overlapping nodes Adam Litke
2008-08-20 18:11 ` Dave Hansen
2008-08-20 19:55 ` Adam Litke [this message]
2008-08-21 11:33 ` [BUG] [PATCH v2] " Mel Gorman
2008-08-26 9:29 ` Andy Whitcroft
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