vmstat: mlocked pages statistics
[linux-2.6.git] / mm / mlock.c
index 8b47835..bce1b22 100644 (file)
@@ -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);
+               }
        }
 }