diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index f7d0b64b9d35..b98084e1f5b0 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2535,8 +2535,13 @@ static inline int task_on_rq_migrating(struct task_struct *p)
 #define WF_EXEC			0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */
 #define WF_FORK			0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */
 #define WF_TTWU			0x08 /* Wakeup;            maps to SD_BALANCE_WAKE */
-
-#define WF_SYNC			0x10 /* Waker goes to sleep after wakeup */
+/*
+ * Hint that the caller expects the waker to sleep soon.
+ * Scheduler classes may use it for placement or preemption.
+ * Callers must not rely on it to prevent migration,
+ * preserve CPU locality or make the wakee run next.
+ */
+#define WF_SYNC			0x10
 #define WF_MIGRATED		0x20 /* Internal use, task got migrated */
 #define WF_CURRENT_CPU		0x40 /* Prefer to move the wakee to the current CPU. */
 #define WF_RQ_SELECTED		0x80 /* ->select_task_rq() was called */
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index d033f600f48c..477e4bf9c01e 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -174,15 +174,11 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key);
  * @mode: which threads
  * @key: opaque value to be passed to wakeup targets
  *
- * The sync wakeup differs that the waker knows that it will schedule
- * away soon, so while the target thread will be woken up, it will not
- * be migrated to another CPU - ie. the two threads are 'synchronized'
- * with each other. This can prevent needless bouncing between CPUs.
+ * Passes WF_SYNC to waitqueue wake functions. The default wake function
+ * forwards it to the scheduler; see WF_SYNC for the hint's semantics.
  *
- * On UP it can prevent extra preemption.
- *
- * If this function wakes up a task, it executes a full memory barrier before
- * accessing the task state.
+ * If this function wakes up a task, it executes a full memory barrier
+ * before accessing the task state.
  */
 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
 			void *key)
@@ -200,15 +196,7 @@ EXPORT_SYMBOL_GPL(__wake_up_sync_key);
  * @mode: which threads
  * @key: opaque value to be passed to wakeup targets
  *
- * The sync wakeup differs in that the waker knows that it will schedule
- * away soon, so while the target thread will be woken up, it will not
- * be migrated to another CPU - ie. the two threads are 'synchronized'
- * with each other. This can prevent needless bouncing between CPUs.
- *
- * On UP it can prevent extra preemption.
- *
- * If this function wakes up a task, it executes a full memory barrier before
- * accessing the task state.
+ * Same as __wake_up_sync_key(), but called with @wq_head->lock held.
  */
 void __wake_up_locked_sync_key(struct wait_queue_head *wq_head,
 			       unsigned int mode, void *key)