vmstat: mlocked pages statistics

Add NR_MLOCK zone page state, which provides a (conservative) count of
mlocked pages (actually, the number of mlocked pages moved off the LRU).

Reworked by lts to fit in with the modified mlock page support in the
Reclaim Scalability series.

[kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo]
[lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 135840cd7feb..05b805020be2 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -45,6 +45,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
                 UNEVICTABLE_PGCULLED,   /* culled to noreclaim list */
                 UNEVICTABLE_PGSCANNED,  /* scanned for reclaimability */
                 UNEVICTABLE_PGRESCUED,  /* rescued from noreclaim list */
+                UNEVICTABLE_PGMLOCKED,
+                UNEVICTABLE_PGMUNLOCKED,
+                UNEVICTABLE_PGCLEARED,  /* on COW, page truncate */
+                UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */
 #endif
                 NR_VM_EVENT_ITEMS
 };