[PATCHv4 07/25] thp, vmstats: add counters for huge file pages

[Kirill A. Shutemov]

THP_FILE_ALLOC: how many times huge page was allocated and put page
cache.

THP_FILE_MAPPED: how many times file huge page was mapped.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 include/linux/vm_event_item.h | 7 +++++++
 mm/memory.c                   | 1 +
 mm/vmstat.c                   | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index ec084321fe09..42604173f122 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -70,6 +70,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		THP_FAULT_FALLBACK,
 		THP_COLLAPSE_ALLOC,
 		THP_COLLAPSE_ALLOC_FAILED,
+		THP_FILE_ALLOC,
+		THP_FILE_MAPPED,
 		THP_SPLIT_PAGE,
 		THP_SPLIT_PAGE_FAILED,
 		THP_DEFERRED_SPLIT_PAGE,
@@ -100,4 +102,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		NR_VM_EVENT_ITEMS
 };
 
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+#define THP_FILE_ALLOC ({ BUILD_BUG(); 0; })
+#define THP_FILE_MAPPED ({ BUILD_BUG(); 0; })
+#endif
+
 #endif		/* VM_EVENT_ITEM_H_INCLUDED */
diff --git a/mm/memory.c b/mm/memory.c
index 0109db96fdff..f7a73b6cabac 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2885,6 +2885,7 @@ static int do_set_pmd(struct fault_env *fe, struct page *page)
 
 	/* fault is handled */
 	ret = 0;
+	count_vm_event(THP_FILE_MAPPED);
 out:
 	spin_unlock(fe->ptl);
 	return ret;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 943b37f17007..78e94198b35f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -847,6 +847,8 @@ const char * const vmstat_text[] = {
 	"thp_fault_fallback",
 	"thp_collapse_alloc",
 	"thp_collapse_alloc_failed",
+	"thp_file_alloc",
+	"thp_file_mapped",
 	"thp_split_page",
 	"thp_split_page_failed",
 	"thp_deferred_split_page",
-- 
2.7.0