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authorJianguo Wu <wujianguo@huawei.com>2012-10-08 16:33:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:54 +0900
commit7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125 (patch)
tree10328fcb468647ba678e022911d5c2005080f309 /mm/page_alloc.c
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 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 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8ac593893e6e..00750bc08a3a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6087,3 +6087,37 @@ void dump_page(struct page *page)
dump_page_flags(page->flags);
mem_cgroup_print_bad_page(page);
}
+
+/* reset zone->present_pages */
+void reset_zone_present_pages(void)
+{
+ struct zone *z;
+ int i, nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ z = NODE_DATA(nid)->node_zones + i;
+ z->present_pages = 0;
+ }
+ }
+}
+
+/* calculate zone's present pages in buddy system */
+void fixup_zone_present_pages(int nid, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ struct zone *z;
+ unsigned long zone_start_pfn, zone_end_pfn;
+ int i;
+
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ z = NODE_DATA(nid)->node_zones + i;
+ zone_start_pfn = z->zone_start_pfn;
+ zone_end_pfn = zone_start_pfn + z->spanned_pages;
+
+ /* if the two regions intersect */
+ if (!(zone_start_pfn >= end_pfn || zone_end_pfn <= start_pfn))
+ z->present_pages += min(end_pfn, zone_end_pfn) -
+ max(start_pfn, zone_start_pfn);
+ }
+}