mlock: count attempts to free mlocked page

Allow free of mlock()ed pages.  This shouldn't happen, but during
developement, it occasionally did.

This patch allows us to survive that condition, while keeping the
statistics and events correct for debug.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 05b805020be2..9cd3ab0f554d 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -49,6 +49,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
                 UNEVICTABLE_PGMUNLOCKED,
                 UNEVICTABLE_PGCLEARED,  /* on COW, page truncate */
                 UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */
+                UNEVICTABLE_MLOCKFREED,
 #endif
                 NR_VM_EVENT_ITEMS
 };