3 files changed, 74 insertions, 0 deletions

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 7af8cb836e78..8b67cf837ca9 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -154,6 +154,7 @@ struct mempolicy *get_vma_policy(struct task_struct *task,
 
 extern void numa_default_policy(void);
 extern void numa_policy_init(void);
+extern void numa_policy_rebind(const nodemask_t *old, const nodemask_t *new);
 extern struct mempolicy default_policy;
 
 #else
@@ -226,6 +227,11 @@ static inline void numa_default_policy(void)
 {
 }
 
+static inline void numa_policy_rebind(const nodemask_t *old,
+                                        const nodemask_t *new)
+{
+}
+
 #endif /* CONFIG_NUMA */
 #endif /* __KERNEL__ */
 
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 6633f3fb6417..5a737ed9dac7 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -32,6 +32,7 @@
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/list.h>
+#include <linux/mempolicy.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/mount.h>
@@ -600,6 +601,7 @@ static void refresh_mems(void)
 
         if (current->cpuset_mems_generation != my_cpusets_mem_gen) {
                 struct cpuset *cs;
+                nodemask_t oldmem = current->mems_allowed;
 
                 down(&callback_sem);
                 task_lock(current);
@@ -608,6 +610,8 @@ static void refresh_mems(void)
                 current->cpuset_mems_generation = cs->mems_generation;
                 task_unlock(current);
                 up(&callback_sem);
+                if (!nodes_equal(oldmem, current->mems_allowed))
+                        numa_policy_rebind(&oldmem, &current->mems_allowed);
         }
 }
 
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);
+}