thp, vmstat: implement HZP_ALLOC and HZP_ALLOC_FAILED events

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>

diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt
index 8f5b41db314cfe0f9c6e1e978cdfd315ddf26019..60aeedd54615328c00937691685066f9348c0fe5 100644 (file)
--- a/Documentation/vm/transhuge.txt
+++ b/Documentation/vm/transhuge.txt
@@ -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

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 3d3114594370118addc16ee1156e9b19f6d97fef..fe786f07d2bd9e0d3149fd72f8c629609e94d89e 100644 (file)
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -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
 };

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d89220cb1d9fc69942362ff3871042e469409879..9a5d45dfad44ab86722e005dd208c6444ddf69f5 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -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();

diff --git a/mm/vmstat.c b/mm/vmstat.c
index c7370579111b872943c56bd694dc0bd02121092d..5da4b19023c30065cd8a32e875497fb51813d66c 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -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 */