4 files changed, 20 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
 };
diff --git a/mm/internal.h b/mm/internal.h
index 1cfbf2e2bc9e..e4e728bdf324 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -146,6 +146,22 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page)
         }
 }
 
+/*
+ * free_page_mlock() -- clean up attempts to free and mlocked() page.
+ * Page should not be on lru, so no need to fix that up.
+ * free_pages_check() will verify...
+ */
+static inline void free_page_mlock(struct page *page)
+{
+        if (unlikely(TestClearPageMlocked(page))) {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                __dec_zone_page_state(page, NR_MLOCK);
+                __count_vm_event(UNEVICTABLE_MLOCKFREED);
+                local_irq_restore(flags);
+        }
+}
 
 #else /* CONFIG_UNEVICTABLE_LRU */
 static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
@@ -155,6 +171,7 @@ static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
 static inline void clear_page_mlock(struct page *page) { }
 static inline void mlock_vma_page(struct page *page) { }
 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
+static inline void free_page_mlock(struct page *page) { }
 
 #endif /* CONFIG_UNEVICTABLE_LRU */
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5886586fde6c..cfbadad75d1d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -454,6 +454,7 @@ static inline void __free_one_page(struct page *page,
 
 static inline int free_pages_check(struct page *page)
 {
+        free_page_mlock(page);
         if (unlikely(page_mapcount(page) |
                 (page->mapping != NULL)  |
                 (page_get_page_cgroup(page) != NULL) |
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 9e28abc0a0b9..9343227c5c60 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -689,6 +689,7 @@ static const char * const vmstat_text[] = {
         "unevictable_pgs_munlocked",
         "unevictable_pgs_cleared",
         "unevictable_pgs_stranded",
+        "unevictable_pgs_mlockfreed",
 #endif
 #endif
 };