1 files changed, 23 insertions, 3 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 501ab637b94b..5280272cce3e 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1344,6 +1344,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
         hrtick_update(rq);
 }
 
+static void set_next_buddy(struct sched_entity *se);
+
 /*
  * The dequeue_task method is called before nr_running is
  * decreased. We remove the task from the rbtree and
@@ -1353,14 +1355,22 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 {
         struct cfs_rq *cfs_rq;
         struct sched_entity *se = &p->se;
+        int task_sleep = flags & DEQUEUE_SLEEP;
 
         for_each_sched_entity(se) {
                 cfs_rq = cfs_rq_of(se);
                 dequeue_entity(cfs_rq, se, flags);
 
                 /* Don't dequeue parent if it has other entities besides us */
-                if (cfs_rq->load.weight)
+                if (cfs_rq->load.weight) {
+                        /*
+                         * Bias pick_next to pick a task from this cfs_rq, as
+                         * p is sleeping when it is within its sched_slice.
+                         */
+                        if (task_sleep && parent_entity(se))
+                                set_next_buddy(parent_entity(se));
                         break;
+                }
                 flags |= DEQUEUE_SLEEP;
         }
 
@@ -1877,12 +1887,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
         struct sched_entity *se = &curr->se, *pse = &p->se;
         struct cfs_rq *cfs_rq = task_cfs_rq(curr);
         int scale = cfs_rq->nr_running >= sched_nr_latency;
+        int next_buddy_marked = 0;
 
         if (unlikely(se == pse))
                 return;
 
-        if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK))
+        if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
                 set_next_buddy(pse);
+                next_buddy_marked = 1;
+        }
 
         /*
          * We can come here with TIF_NEED_RESCHED already set from new task
@@ -1910,8 +1923,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
         update_curr(cfs_rq);
         find_matching_se(&se, &pse);
         BUG_ON(!pse);
-        if (wakeup_preempt_entity(se, pse) == 1)
+        if (wakeup_preempt_entity(se, pse) == 1) {
+                /*
+                 * Bias pick_next to pick the sched entity that is
+                 * triggering this preemption.
+                 */
+                if (!next_buddy_marked)
+                        set_next_buddy(pse);
                 goto preempt;
+        }
 
         return;