Merge tag 'v4.4.274' into toradex_vf_4.4-next

Linux 4.4.274

1 files changed, 11 insertions, 4 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 3fb2d45c0b42..a2de597604e6 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1351,7 +1351,6 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
 	 */
 	WARN_ON_ONCE(!irqs_disabled());
 
-	debug_work_activate(work);
 
 	/* if draining, only works from the same workqueue are allowed */
 	if (unlikely(wq->flags & __WQ_DRAINING) &&
@@ -1430,6 +1429,7 @@ retry:
 		worklist = &pwq->delayed_works;
 	}
 
+	debug_work_activate(work);
 	insert_work(pwq, work, worklist, work_flags);
 
 	spin_unlock(&pwq->pool->lock);
@@ -3361,17 +3361,24 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq)
 	 * is updated and visible.
 	 */
 	if (!freezable || !workqueue_freezing) {
+		bool kick = false;
+
 		pwq->max_active = wq->saved_max_active;
 
 		while (!list_empty(&pwq->delayed_works) &&
-		       pwq->nr_active < pwq->max_active)
+		       pwq->nr_active < pwq->max_active) {
 			pwq_activate_first_delayed(pwq);
+			kick = true;
+		}
 
 		/*
 		 * Need to kick a worker after thawed or an unbound wq's
-		 * max_active is bumped.  It's a slow path.  Do it always.
+		 * max_active is bumped. In realtime scenarios, always kicking a
+		 * worker will cause interference on the isolated cpu cores, so
+		 * let's kick iff work items were activated.
 		 */
-		wake_up_worker(pwq->pool);
+		if (kick)
+			wake_up_worker(pwq->pool);
 	} else {
 		pwq->max_active = 0;
 	}