[PATCH v10 23/25] mm: add speculative page fault vmstats

[Laurent Dufour]

Add speculative_pgfault vmstat counter to count successful speculative page
fault handling.

Also fixing a minor typo in include/linux/vm_event_item.h.

Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
 include/linux/vm_event_item.h | 3 +++
 mm/memory.c                   | 1 +
 mm/vmstat.c                   | 5 ++++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 5c7f010676a7..a240acc09684 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -111,6 +111,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		SWAP_RA,
 		SWAP_RA_HIT,
 #endif
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+		SPECULATIVE_PGFAULT,
+#endif
 		NR_VM_EVENT_ITEMS
 };
 
diff --git a/mm/memory.c b/mm/memory.c
index 425f07e0bf38..1cd5bc000643 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4508,6 +4508,7 @@ int __handle_speculative_fault(struct mm_struct *mm, unsigned long address,
 	 * If there is no need to retry, don't return the vma to the caller.
 	 */
 	if (ret != VM_FAULT_RETRY) {
+		count_vm_event(SPECULATIVE_PGFAULT);
 		put_vma(vmf.vma);
 		*vma = NULL;
 	}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 536332e988b8..c6b49bfa8139 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1289,7 +1289,10 @@ const char * const vmstat_text[] = {
 	"swap_ra",
 	"swap_ra_hit",
 #endif
-#endif /* CONFIG_VM_EVENTS_COUNTERS */
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+	"speculative_pgfault"
+#endif
+#endif /* CONFIG_VM_EVENT_COUNTERS */
 };
 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 
-- 
2.7.4