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
..
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
Makefile	[PATCH] ia64: ioremap: check EFI for valid memory attributes	2006-03-26 08:56:54 -08:00
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