Commit 344c790e authored by Adam Litke's avatar Adam Litke Committed by Linus Torvalds

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: default avatarAdam Litke <>
Acked-by: default avatarMel Gorman <>
Cc: Dave Hansen <>
Cc: Nishanth Aravamudan <>
Cc: Andy Whitcroft <>
Cc: <>		[2.6.25.x, 2.6.26.x]
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 169ccbd4
......@@ -694,6 +694,9 @@ static int move_freepages(struct zone *zone,
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))) {
......@@ -2516,6 +2519,10 @@ static void setup_zone_migrate_reserve(struct zone *zone)
page = pfn_to_page(pfn);
/* Watch out for overlapping nodes */
if (page_to_nid(page) != zone_to_nid(zone))
/* Blocks with reserved pages will never free, skip them. */
if (PageReserved(page))
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