ttu don't need to return SWAP_MLOCK. Instead, just return SWAP_FAIL
because it means the page is not-swappable so it should move to
another LRU list(active or unevictable). putback friends will
move it to right list depending on the page's LRU flag.

Signed-off-by: Minchan Kim <minc...@kernel.org>
---
 include/linux/rmap.h |  1 -
 mm/rmap.c            |  3 +--
 mm/vmscan.c          | 20 +++++++-------------
 3 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 1b0cd4c..3630d4d 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -297,6 +297,5 @@ static inline int page_mkclean(struct page *page)
 #define SWAP_SUCCESS   0
 #define SWAP_AGAIN     1
 #define SWAP_FAIL      2
-#define SWAP_MLOCK     3
 
 #endif /* _LINUX_RMAP_H */
diff --git a/mm/rmap.c b/mm/rmap.c
index 9c51065..38e8ab1 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1324,7 +1324,7 @@ static int try_to_unmap_one(struct page *page, struct 
vm_area_struct *vma,
                                         */
                                        mlock_vma_page(page);
                                }
-                               ret = SWAP_MLOCK;
+                               ret = SWAP_FAIL;
                                page_vma_mapped_walk_done(&pvmw);
                                break;
                        }
@@ -1501,7 +1501,6 @@ static int page_mapcount_is_zero(struct page *page)
  * SWAP_SUCCESS        - we succeeded in removing all mappings
  * SWAP_AGAIN  - we missed a mapping, try again later
  * SWAP_FAIL   - the page is unswappable
- * SWAP_MLOCK  - page is mlocked.
  */
 int try_to_unmap(struct page *page, enum ttu_flags flags)
 {
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b8fd656..2a208f0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -982,7 +982,7 @@ static unsigned long shrink_page_list(struct list_head 
*page_list,
                sc->nr_scanned++;
 
                if (unlikely(!page_evictable(page)))
-                       goto cull_mlocked;
+                       goto activate_locked;
 
                if (!sc->may_unmap && page_mapped(page))
                        goto keep_locked;
@@ -1147,8 +1147,6 @@ static unsigned long shrink_page_list(struct list_head 
*page_list,
                                goto activate_locked;
                        case SWAP_AGAIN:
                                goto keep_locked;
-                       case SWAP_MLOCK:
-                               goto cull_mlocked;
                        case SWAP_SUCCESS:
                                ; /* try to free the page below */
                        }
@@ -1290,20 +1288,16 @@ static unsigned long shrink_page_list(struct list_head 
*page_list,
                list_add(&page->lru, &free_pages);
                continue;
 
-cull_mlocked:
-               if (PageSwapCache(page))
-                       try_to_free_swap(page);
-               unlock_page(page);
-               list_add(&page->lru, &ret_pages);
-               continue;
-
 activate_locked:
                /* Not a candidate for swapping, so reclaim swap space. */
-               if (PageSwapCache(page) && mem_cgroup_swap_full(page))
+               if (PageSwapCache(page) && (mem_cgroup_swap_full(page) ||
+                                               PageMlocked(page)))
                        try_to_free_swap(page);
                VM_BUG_ON_PAGE(PageActive(page), page);
-               SetPageActive(page);
-               pgactivate++;
+               if (!PageMlocked(page)) {
+                       SetPageActive(page);
+                       pgactivate++;
+               }
 keep_locked:
                unlock_page(page);
 keep:
-- 
2.7.4

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