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 <redacted>
---
 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"