diff options
| author | Jianguo Wu <wujianguo@huawei.com> | 2012-10-08 16:33:06 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:54 +0900 |
| commit | 7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125 (patch) | |
| tree | 10328fcb468647ba678e022911d5c2005080f309 /include | |
| parent | 05106e6a54aed321191b4bb5c9ee09538cbad3b1 (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
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index bcaab4e6fe9..fa068040273 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1684,5 +1684,9 @@ static inline unsigned int debug_guardpage_minorder(void) { return 0; } static inline bool page_is_guard(struct page *page) { return false; } #endif /* CONFIG_DEBUG_PAGEALLOC */ +extern void reset_zone_present_pages(void); +extern void fixup_zone_present_pages(int nid, unsigned long start_pfn, + unsigned long end_pfn); + #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ |