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Commit 7f1290f2 authored by Jianguo Wu's avatar Jianguo Wu Committed by Linus Torvalds
Browse files

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: default avatarJianguo Wu <wujianguo@huawei.com>
Signed-off-by: default avatarJiang Liu <jiang.liu@huawei.com>
Reported-by: default avatarPetr Tesarik <ptesarik@suse.cz>
Tested-by: default avatarPetr 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 05106e6a

arch/ia64/mm/init.c

+1 −0
Original line number Diff line number Diff line
@@ -637,6 +637,7 @@ mem_init (void) 


	high_memory = __va(max_low_pfn * PAGE_SIZE);



	reset_zone_present_pages();

	for_each_online_pgdat(pgdat)

		if (pgdat->bdata->node_bootmem_map)

			totalram_pages += free_all_bootmem_node(pgdat);

include/linux/mm.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */

mm/bootmem.c

+9 −1
Original line number Diff line number Diff line
@@ -198,6 +198,8 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) 
			int order = ilog2(BITS_PER_LONG);



			__free_pages_bootmem(pfn_to_page(start), order);

			fixup_zone_present_pages(page_to_nid(pfn_to_page(start)),

					start, start + BITS_PER_LONG);

			count += BITS_PER_LONG;

			start += BITS_PER_LONG;

		} else {
@@ -208,6 +210,9 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) 
				if (vec & 1) {

					page = pfn_to_page(start + off);

					__free_pages_bootmem(page, 0);

					fixup_zone_present_pages(

						page_to_nid(page),

						start + off, start + off + 1);

					count++;

				}

				vec >>= 1;
@@ -221,8 +226,11 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) 
	pages = bdata->node_low_pfn - bdata->node_min_pfn;

	pages = bootmem_bootmap_pages(pages);

	count += pages;

	while (pages--)

	while (pages--) {

		fixup_zone_present_pages(page_to_nid(page),

				page_to_pfn(page), page_to_pfn(page) + 1);

		__free_pages_bootmem(page++, 0);

	}



	bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);

mm/memory_hotplug.c

+7 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ static void get_page_bootmem(unsigned long info, struct page *page, 
void __ref put_page_bootmem(struct page *page)

{

	unsigned long type;

	struct zone *zone;



	type = (unsigned long) page->lru.next;

	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
@@ -116,6 +117,12 @@ void __ref put_page_bootmem(struct page *page) 
		set_page_private(page, 0);

		INIT_LIST_HEAD(&page->lru);

		__free_pages_bootmem(page, 0);



		zone = page_zone(page);

		zone_span_writelock(zone);

		zone->present_pages++;

		zone_span_writeunlock(zone);

		totalram_pages++;

	}



}

mm/nobootmem.c

+3 −0
Original line number Diff line number Diff line
@@ -116,6 +116,8 @@ static unsigned long __init __free_memory_core(phys_addr_t start, 
		return 0;



	__free_pages_memory(start_pfn, end_pfn);

	fixup_zone_present_pages(pfn_to_nid(start >> PAGE_SHIFT),

			start_pfn, end_pfn);



	return end_pfn - start_pfn;

}
@@ -126,6 +128,7 @@ unsigned long __init free_low_memory_core_early(int nodeid) 
	phys_addr_t start, end, size;

	u64 i;



	reset_zone_present_pages();

	for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL)

		count += __free_memory_core(start, end);