path: root/arch/ia64/mm
diff options
authorJianguo Wu <>2012-10-08 16:33:06 -0700
committerLinus Torvalds <>2012-10-09 16:22:54 +0900
commit7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125 (patch)
tree10328fcb468647ba678e022911d5c2005080f309 /arch/ia64/mm
parent05106e6a54aed321191b4bb5c9ee09538cbad3b1 (diff)
mm: fix-up zone present pages
I think zone->present_pages indicates pages that buddy system can management, it should be: zone->present_pages = spanned pages - absent pages - bootmem pages, but is now: zone->present_pages = spanned pages - absent pages - memmap pages. spanned pages: total size, including holes. absent pages: holes. bootmem pages: pages used in system boot, managed by bootmem allocator. memmap pages: pages used by page structs. This may cause zone->present_pages less than it should be. For example, numa node 1 has ZONE_NORMAL and ZONE_MOVABLE, it's memmap and other bootmem will be allocated from ZONE_MOVABLE, so ZONE_NORMAL's present_pages should be spanned pages - absent pages, but now it also minus memmap pages(free_area_init_core), which are actually allocated from ZONE_MOVABLE. When offlining all memory of a zone, this will cause zone->present_pages less than 0, because present_pages is unsigned long type, it is actually a very large integer, it indirectly caused zone->watermark[WMARK_MIN] becomes a large integer(setup_per_zone_wmarks()), than cause totalreserve_pages become a large integer(calculate_totalreserve_pages()), and finally cause memory allocating failure when fork process(__vm_enough_memory()). [root@localhost ~]# dmesg -bash: fork: Cannot allocate memory I think the bug described in is also caused by wrong zone present pages. This patch intends to fix-up zone->present_pages when memory are freed to buddy system on x86_64 and IA64 platforms. Signed-off-by: Jianguo Wu <> Signed-off-by: Jiang Liu <> Reported-by: Petr Tesarik <> Tested-by: Petr Tesarik <> Cc: "Luck, Tony" <> Cc: Mel Gorman <> Cc: Yinghai Lu <> Cc: Minchan Kim <> Cc: Johannes Weiner <> Cc: David Rientjes <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'arch/ia64/mm')
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 082e383c1b6f..acd5b68e8871 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -637,6 +637,7 @@ mem_init (void)
high_memory = __va(max_low_pfn * PAGE_SIZE);
+ reset_zone_present_pages();
if (pgdat->bdata->node_bootmem_map)
totalram_pages += free_all_bootmem_node(pgdat);