The patch titled mm: make setup_zone_migrate_reserve() aware of overlapping nodes has been added to the -mm tree. Its filename is mm-make-setup_zone_migrate_reserve-aware-of-overlapping-nodes.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mm: make setup_zone_migrate_reserve() aware of overlapping nodes From: Adam Litke <agl@xxxxxxxxxx> 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@xxxxxxxxxx> Acked-by: Mel Gorman <mel@xxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Cc: Nishanth Aravamudan <nacc@xxxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> [2.6.25.x, 2.6.26.x] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff -puN mm/page_alloc.c~mm-make-setup_zone_migrate_reserve-aware-of-overlapping-nodes mm/page_alloc.c --- a/mm/page_alloc.c~mm-make-setup_zone_migrate_reserve-aware-of-overlapping-nodes +++ a/mm/page_alloc.c @@ -694,6 +694,9 @@ static int move_freepages(struct zone *z #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(s 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; _ Patches currently in -mm which might be from agl@xxxxxxxxxx are mm-make-setup_zone_migrate_reserve-aware-of-overlapping-nodes.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html