1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 10131fdaff70..ed0ff443f036 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -949,6 +949,8 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
 static void cpuset_change_task_nodemask(struct task_struct *tsk,
                                         nodemask_t *newmems)
 {
+        bool masks_disjoint = !nodes_intersects(*newmems, tsk->mems_allowed);
+
 repeat:
         /*
          * Allow tasks that have access to memory reserves because they have
@@ -963,7 +965,6 @@ repeat:
         nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
         mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
 
-
         /*
          * ensure checking ->mems_allowed_change_disable after setting all new
          * allowed nodes.
@@ -980,9 +981,11 @@ repeat:
 
         /*
          * Allocation of memory is very fast, we needn't sleep when waiting
-         * for the read-side.
+         * for the read-side.  No wait is necessary, however, if at least one
+         * node remains unchanged.
          */
-        while (ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
+        while (masks_disjoint &&
+                        ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
                 task_unlock(tsk);
                 if (!task_curr(tsk))
                         yield();