1 files changed, 36 insertions, 5 deletions

diff --git a/mm/mlock.c b/mm/mlock.c
index 8b478350a2a1..bce1b22c36c2 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -60,6 +60,8 @@ void __clear_page_mlock(struct page *page)
                 return;
         }
 
+        dec_zone_page_state(page, NR_MLOCK);
+        count_vm_event(UNEVICTABLE_PGCLEARED);
         if (!isolate_lru_page(page)) {
                 putback_lru_page(page);
         } else {
@@ -69,6 +71,9 @@ void __clear_page_mlock(struct page *page)
                 lru_add_drain_all();
                 if (!isolate_lru_page(page))
                         putback_lru_page(page);
+                else if (PageUnevictable(page))
+                        count_vm_event(UNEVICTABLE_PGSTRANDED);
+
         }
 }
 
@@ -80,8 +85,12 @@ void mlock_vma_page(struct page *page)
 {
         BUG_ON(!PageLocked(page));
 
-        if (!TestSetPageMlocked(page) && !isolate_lru_page(page))
-                putback_lru_page(page);
+        if (!TestSetPageMlocked(page)) {
+                inc_zone_page_state(page, NR_MLOCK);
+                count_vm_event(UNEVICTABLE_PGMLOCKED);
+                if (!isolate_lru_page(page))
+                        putback_lru_page(page);
+        }
 }
 
 /*
@@ -106,9 +115,31 @@ static void munlock_vma_page(struct page *page)
 {
         BUG_ON(!PageLocked(page));
 
-        if (TestClearPageMlocked(page) && !isolate_lru_page(page)) {
-                try_to_munlock(page);
-                putback_lru_page(page);
+        if (TestClearPageMlocked(page)) {
+                dec_zone_page_state(page, NR_MLOCK);
+                if (!isolate_lru_page(page)) {
+                        int ret = try_to_munlock(page);
+                        /*
+                         * did try_to_unlock() succeed or punt?
+                         */
+                        if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN)
+                                count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+
+                        putback_lru_page(page);
+                } else {
+                        /*
+                         * We lost the race.  let try_to_unmap() deal
+                         * with it.  At least we get the page state and
+                         * mlock stats right.  However, page is still on
+                         * the noreclaim list.  We'll fix that up when
+                         * the page is eventually freed or we scan the
+                         * noreclaim list.
+                         */
+                        if (PageUnevictable(page))
+                                count_vm_event(UNEVICTABLE_PGSTRANDED);
+                        else
+                                count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+                }
         }
 }