mlock: mlocked pages are unevictable

[linux-2.6-block.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index dfb342e0db9b342736d8211c43fb46bfe1fdfd1d..e5aaaad159ef236a1580faafaf7e663547f5965e 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -582,11 +582,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 
                sc->nr_scanned++;
 
-               if (unlikely(!page_evictable(page, NULL))) {
-                       unlock_page(page);
-                       putback_lru_page(page);
-                       continue;
-               }
+               if (unlikely(!page_evictable(page, NULL)))
+                       goto cull_mlocked;
 
                if (!sc->may_swap && page_mapped(page))
                        goto keep_locked;
@@ -624,9 +621,19 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                 * Anonymous process memory has backing store?
                 * Try to allocate it some swap space here.
                 */
-               if (PageAnon(page) && !PageSwapCache(page))
+               if (PageAnon(page) && !PageSwapCache(page)) {
+                       switch (try_to_munlock(page)) {
+                       case SWAP_FAIL:         /* shouldn't happen */
+                       case SWAP_AGAIN:
+                               goto keep_locked;
+                       case SWAP_MLOCK:
+                               goto cull_mlocked;
+                       case SWAP_SUCCESS:
+                               ; /* fall thru'; add to swap cache */
+                       }
                        if (!add_to_swap(page, GFP_ATOMIC))
                                goto activate_locked;
+               }
 #endif /* CONFIG_SWAP */
 
                mapping = page_mapping(page);
@@ -641,6 +648,8 @@ 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 */
                        }
@@ -731,6 +740,11 @@ free_it:
                }
                continue;
 
+cull_mlocked:
+               unlock_page(page);
+               putback_lru_page(page);
+               continue;
+
 activate_locked:
                /* Not a candidate for swapping, so reclaim swap space. */
                if (PageSwapCache(page) && vm_swap_full())
@@ -742,7 +756,7 @@ keep_locked:
                unlock_page(page);
 keep:
                list_add(&page->lru, &ret_pages);
-               VM_BUG_ON(PageLRU(page));
+               VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
        }
        list_splice(&ret_pages, page_list);
        if (pagevec_count(&freed_pvec))
@@ -2329,12 +2343,13 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
  * @vma: the VMA in which the page is or will be mapped, may be NULL
  *
  * Test whether page is evictable--i.e., should be placed on active/inactive
- * lists vs unevictable list.
+ * lists vs unevictable list.  The vma argument is !NULL when called from the
+ * fault path to determine how to instantate a new page.
  *
  * Reasons page might not be evictable:
  * (1) page's mapping marked unevictable
+ * (2) page is part of an mlocked VMA
  *
- * TODO - later patches
  */
 int page_evictable(struct page *page, struct vm_area_struct *vma)
 {
@@ -2342,7 +2357,8 @@ int page_evictable(struct page *page, struct vm_area_struct *vma)
        if (mapping_unevictable(page_mapping(page)))
                return 0;
 
-       /* TODO:  test page [!]evictable conditions */
+       if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page)))
+               return 0;
 
        return 1;
 }