4 files changed, 16 insertions, 1 deletions

diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt
index 8f5b41db314c..60aeedd54615 100644
--- 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 3d3114594370..fe786f07d2bd 100644
--- 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 d89220cb1d9f..9a5d45dfad44 100644
--- 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 c7370579111b..5da4b19023c3 100644
--- 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 */