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

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
......@@ -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);
......
......@@ -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 */
......@@ -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);
......
......@@ -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++;
}
}
......
......@@ -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);
......
......@@ -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);
}
}
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