mm: remove SWAP_MLOCK in ttu

ttu doesn'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.

Link: http://lkml.kernel.org/r/1489555493-14659-6-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 1b0cd4cf68e33e0e3a5dd0962c71b19aca4e06a7..3630d4dcee1349bdc656cb391432ff71d53f1e1d 100644 (file)
--- 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 171db511aa8c1dea1b72273a1cd25368512fd34a..45f41d4fa670f855dac04e3d08a378a1978980c2 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1329,7 +1329,7 @@ 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;
                        }
@@ -1506,7 +1506,6 @@ 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 f1fd388454bd04254df86097300b395643bf3747..cfd2651966a844921c3795521a1e01414b04aa03 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -987,7 +987,7 @@ 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;
@@ -1152,8 +1152,6 @@ 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 */
                        }
@@ -1295,20 +1293,16 @@ free_it:
                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: