---

yaml
---
r: 24894
b: refs/heads/master
c: e4e364e
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2741a559a01e1ba9bf87285569dc1a104d134ecf
+refs/heads/master: e4e364e865b382f9d99c7fc230ec2ce7df21257a

trunk/kernel/cpuset.c

@@ -833,6 +833,55 @@ static int update_cpumask(struct cpuset *cs, char *buf)
 	return 0;
 }
 
+/*
+ * cpuset_migrate_mm
+ *
+ *    Migrate memory region from one set of nodes to another.
+ *
+ *    Temporarilly set tasks mems_allowed to target nodes of migration,
+ *    so that the migration code can allocate pages on these nodes.
+ *
+ *    Call holding manage_mutex, so our current->cpuset won't change
+ *    during this call, as manage_mutex holds off any attach_task()
+ *    calls.  Therefore we don't need to take task_lock around the
+ *    call to guarantee_online_mems(), as we know no one is changing
+ *    our tasks cpuset.
+ *
+ *    Hold callback_mutex around the two modifications of our tasks
+ *    mems_allowed to synchronize with cpuset_mems_allowed().
+ *
+ *    While the mm_struct we are migrating is typically from some
+ *    other task, the task_struct mems_allowed that we are hacking
+ *    is for our current task, which must allocate new pages for that
+ *    migrating memory region.
+ *
+ *    We call cpuset_update_task_memory_state() before hacking
+ *    our tasks mems_allowed, so that we are assured of being in
+ *    sync with our tasks cpuset, and in particular, callbacks to
+ *    cpuset_update_task_memory_state() from nested page allocations
+ *    won't see any mismatch of our cpuset and task mems_generation
+ *    values, so won't overwrite our hacked tasks mems_allowed
+ *    nodemask.
+ */
+
+static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
+							const nodemask_t *to)
+{
+	struct task_struct *tsk = current;
+
+	cpuset_update_task_memory_state();
+
+	mutex_lock(&callback_mutex);
+	tsk->mems_allowed = *to;
+	mutex_unlock(&callback_mutex);
+
+	do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
+
+	mutex_lock(&callback_mutex);
+	guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed);
+	mutex_unlock(&callback_mutex);
+}
+
 /*
  * Handle user request to change the 'mems' memory placement
  * of a cpuset.  Needs to validate the request, update the
@@ -945,10 +994,8 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 		struct mm_struct *mm = mmarray[i];
 
 		mpol_rebind_mm(mm, &cs->mems_allowed);
-		if (migrate) {
-			do_migrate_pages(mm, &oldmem, &cs->mems_allowed,
-							MPOL_MF_MOVE_ALL);
-		}
+		if (migrate)
+			cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
 		mmput(mm);
 	}
 
@@ -1184,7 +1231,7 @@ static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
 	if (mm) {
 		mpol_rebind_mm(mm, &to);
 		if (is_memory_migrate(cs))
-			do_migrate_pages(mm, &from, &to, MPOL_MF_MOVE_ALL);
+			cpuset_migrate_mm(mm, &from, &to);
 		mmput(mm);
 	}