linux-sg2042/arch/ia64/mm
Jianguo Wu 7f1290f2f2 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

  http://marc.info/?l=linux-mm&m=134502182714186&w=2

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 <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reported-by: Petr Tesarik <ptesarik@suse.cz>
Tested-by: Petr Tesarik <ptesarik@suse.cz>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:54 +09:00
..
Makefile [PATCH] ia64: ioremap: check EFI for valid memory attributes 2006-03-26 08:56:54 -08:00
contig.c ia64: Use HAVE_MEMBLOCK_NODE_MAP 2011-12-08 10:22:08 -08:00
discontig.c arch, mm: filter disallowed nodes from arch specific show_mem functions 2011-05-25 08:39:03 -07:00
extable.c [IA64] fix compile error in arch/ia64/mm/extable.c 2009-06-15 09:17:50 -07:00
fault.c readahead: fault retry breaks mmap file read random detection 2012-10-09 16:22:47 +09:00
hugetlbpage.c thp: pte alloc trans splitting 2011-01-13 17:32:40 -08:00
init.c mm: fix-up zone present pages 2012-10-09 16:22:54 +09:00
ioremap.c implement early_io{re,un}map for ia64 2009-12-16 02:45:10 +00:00
numa.c ia64: revert __node_random addition 2010-05-30 10:08:03 -07:00
tlb.c [IA64] Fix spinaphore down_spin() 2010-06-30 10:46:16 -07:00