1 files changed, 64 insertions, 0 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 2076b1542b8a..5abc57c2b8bd 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -457,6 +457,7 @@ long do_get_mempolicy(int *policy, nodemask_t *nmask,
         struct vm_area_struct *vma = NULL;
         struct mempolicy *pol = current->mempolicy;
 
+        cpuset_update_current_mems_allowed();
         if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR))
                 return -EINVAL;
         if (flags & MPOL_F_ADDR) {
@@ -1206,3 +1207,66 @@ void numa_default_policy(void)
 {
         do_set_mempolicy(MPOL_DEFAULT, NULL);
 }
+
+/* Migrate a policy to a different set of nodes */
+static void rebind_policy(struct mempolicy *pol, const nodemask_t *old,
+                                                        const nodemask_t *new)
+{
+        nodemask_t tmp;
+
+        if (!pol)
+                return;
+
+        switch (pol->policy) {
+        case MPOL_DEFAULT:
+                break;
+        case MPOL_INTERLEAVE:
+                nodes_remap(tmp, pol->v.nodes, *old, *new);
+                pol->v.nodes = tmp;
+                current->il_next = node_remap(current->il_next, *old, *new);
+                break;
+        case MPOL_PREFERRED:
+                pol->v.preferred_node = node_remap(pol->v.preferred_node,
+                                                                *old, *new);
+                break;
+        case MPOL_BIND: {
+                nodemask_t nodes;
+                struct zone **z;
+                struct zonelist *zonelist;
+
+                nodes_clear(nodes);
+                for (z = pol->v.zonelist->zones; *z; z++)
+                        node_set((*z)->zone_pgdat->node_id, nodes);
+                nodes_remap(tmp, nodes, *old, *new);
+                nodes = tmp;
+
+                zonelist = bind_zonelist(&nodes);
+
+                /* If no mem, then zonelist is NULL and we keep old zonelist.
+                 * If that old zonelist has no remaining mems_allowed nodes,
+                 * then zonelist_policy() will "FALL THROUGH" to MPOL_DEFAULT.
+                 */
+
+                if (zonelist) {
+                        /* Good - got mem - substitute new zonelist */
+                        kfree(pol->v.zonelist);
+                        pol->v.zonelist = zonelist;
+                }
+                break;
+        }
+        default:
+                BUG();
+                break;
+        }
+}
+
+/*
+ * Someone moved this task to different nodes.  Fixup mempolicies.
+ *
+ * TODO - fixup current->mm->vma and shmfs/tmpfs/hugetlbfs policies as well,
+ * once we have a cpuset mechanism to mark which cpuset subtree is migrating.
+ */
+void numa_policy_rebind(const nodemask_t *old, const nodemask_t *new)
+{
+        rebind_policy(current->mempolicy, old, new);
+}