mm: make setup_zone_migrate_reserve() aware of overlapping nodes
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.
setup_zone_migrate_reserve() should skip pageblocks in overlapping nodes.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 @@
#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 @@
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;