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thp, vmstat: implement HZP_ALLOC and HZP_ALLOC_FAILED events

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hzp_alloc is incremented every time a huge zero page is successfully
	allocated. It includes allocations which where dropped due
	race with other allocation. Note, it doesn't count every map
	of the huge zero page, only its allocation.

hzp_alloc_failed is incremented if kernel fails to allocate huge zero
	page and falls back to using small pages.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2012-12-12 13:51:09 -08:00 committed by Linus Torvalds
parent 97ae17497e
commit d8a8e1f0da
4 changed files with 16 additions and 1 deletions
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8
Documentation/vm/transhuge.txt
View File

@ -197,6 +197,14 @@ thp_split is incremented every time a huge page is split into base
pages. This can happen for a variety of reasons but a common
reason is that a huge page is old and is being reclaimed.
thp_zero_page_alloc is incremented every time a huge zero page is
successfully allocated. It includes allocations which where
dropped due race with other allocation. Note, it doesn't count
every map of the huge zero page, only its allocation.
thp_zero_page_alloc_failed is incremented if kernel fails to allocate
huge zero page and falls back to using small pages.
As the system ages, allocating huge pages may be expensive as the
system uses memory compaction to copy data around memory to free a
huge page for use. There are some counters in /proc/vmstat to help

2
include/linux/vm_event_item.h
View File

@ -58,6 +58,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_COLLAPSE_ALLOC,
THP_COLLAPSE_ALLOC_FAILED,
THP_SPLIT,
THP_ZERO_PAGE_ALLOC,
THP_ZERO_PAGE_ALLOC_FAILED,
#endif
NR_VM_EVENT_ITEMS
};

5
mm/huge_memory.c
View File

@ -184,8 +184,11 @@ retry:
zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
HPAGE_PMD_ORDER);
if (!zero_page)
if (!zero_page) {
count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
return 0;
}
count_vm_event(THP_ZERO_PAGE_ALLOC);
preempt_disable();
if (cmpxchg(&huge_zero_pfn, 0, page_to_pfn(zero_page))) {
preempt_enable();

2
mm/vmstat.c
View File

@ -801,6 +801,8 @@ const char * const vmstat_text[] = {
"thp_collapse_alloc",
"thp_collapse_alloc_failed",
"thp_split",
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
#endif
#endif /* CONFIG_VM_EVENTS_COUNTERS */