1 files changed, 51 insertions, 48 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3171f884d245..73790188b0eb 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -185,8 +185,8 @@ static struct mempolicy *mpol_new(int mode, nodemask_t *nodes)
 }
 
 static void gather_stats(struct page *, void *);
-static void migrate_page_add(struct vm_area_struct *vma,
-        struct page *page, struct list_head *pagelist, unsigned long flags);
+static void migrate_page_add(struct page *page, struct list_head *pagelist,
+                                unsigned long flags);
 
 /* Scan through pages checking if pages follow certain conditions. */
 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -208,6 +208,17 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                 page = vm_normal_page(vma, addr, *pte);
                 if (!page)
                         continue;
+                /*
+                 * The check for PageReserved here is important to avoid
+                 * handling zero pages and other pages that may have been
+                 * marked special by the system.
+                 *
+                 * If the PageReserved would not be checked here then f.e.
+                 * the location of the zero page could have an influence
+                 * on MPOL_MF_STRICT, zero pages would be counted for
+                 * the per node stats, and there would be useless attempts
+                 * to put zero pages on the migration list.
+                 */
                 if (PageReserved(page))
                         continue;
                 nid = page_to_nid(page);
@@ -216,11 +227,8 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 
                 if (flags & MPOL_MF_STATS)
                         gather_stats(page, private);
-                else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
-                        spin_unlock(ptl);
-                        migrate_page_add(vma, page, private, flags);
-                        spin_lock(ptl);
-                }
+                else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+                        migrate_page_add(page, private, flags);
                 else
                         break;
         } while (pte++, addr += PAGE_SIZE, addr != end);
@@ -309,6 +317,10 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
         int err;
         struct vm_area_struct *first, *vma, *prev;
 
+        /* Clear the LRU lists so pages can be isolated */
+        if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+                lru_add_drain_all();
+
         first = find_vma(mm, start);
         if (!first)
                 return ERR_PTR(-EFAULT);
@@ -519,51 +531,15 @@ long do_get_mempolicy(int *policy, nodemask_t *nmask,
  * page migration
  */
 
-/* Check if we are the only process mapping the page in question */
-static inline int single_mm_mapping(struct mm_struct *mm,
-                        struct address_space *mapping)
-{
-        struct vm_area_struct *vma;
-        struct prio_tree_iter iter;
-        int rc = 1;
-
-        spin_lock(&mapping->i_mmap_lock);
-        vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
-                if (mm != vma->vm_mm) {
-                        rc = 0;
-                        goto out;
-                }
-        list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
-                if (mm != vma->vm_mm) {
-                        rc = 0;
-                        goto out;
-                }
-out:
-        spin_unlock(&mapping->i_mmap_lock);
-        return rc;
-}
-
-/*
- * Add a page to be migrated to the pagelist
- */
-static void migrate_page_add(struct vm_area_struct *vma,
-        struct page *page, struct list_head *pagelist, unsigned long flags)
+static void migrate_page_add(struct page *page, struct list_head *pagelist,
+                                unsigned long flags)
 {
         /*
-         * Avoid migrating a page that is shared by others and not writable.
+         * Avoid migrating a page that is shared with others.
          */
-        if ((flags & MPOL_MF_MOVE_ALL) || !page->mapping || PageAnon(page) ||
-            mapping_writably_mapped(page->mapping) ||
-            single_mm_mapping(vma->vm_mm, page->mapping)) {
-                int rc = isolate_lru_page(page);
-
-                if (rc == 1)
+        if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
+                if (isolate_lru_page(page))
                         list_add(&page->lru, pagelist);
-                /*
-                 * If the isolate attempt was not successful then we just
-                 * encountered an unswappable page. Something must be wrong.
-                 */
-                WARN_ON(rc == 0);
         }
 }
 
@@ -1000,6 +976,33 @@ static unsigned interleave_nodes(struct mempolicy *policy)
         return nid;
 }
 
+/*
+ * Depending on the memory policy provide a node from which to allocate the
+ * next slab entry.
+ */
+unsigned slab_node(struct mempolicy *policy)
+{
+        switch (policy->policy) {
+        case MPOL_INTERLEAVE:
+                return interleave_nodes(policy);
+
+        case MPOL_BIND:
+                /*
+                 * Follow bind policy behavior and start allocation at the
+                 * first node.
+                 */
+                return policy->v.zonelist->zones[0]->zone_pgdat->node_id;
+
+        case MPOL_PREFERRED:
+                if (policy->v.preferred_node >= 0)
+                        return policy->v.preferred_node;
+                /* Fall through */
+
+        default:
+                return numa_node_id();
+        }
+}
+
 /* Do static interleaving for a VMA with known offset. */
 static unsigned offset_il_node(struct mempolicy *pol,
                 struct vm_area_struct *vma, unsigned long off)