Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

[firefly-linux-kernel-4.4.55.git] / kernel / sched_fair.c

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index fdc417504681af17114c9fbf79e809dad02e2e23..a7e50ba185ac0a843ac16604e13a721ca8e4cb8e 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -719,7 +719,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
                __enqueue_entity(cfs_rq, se);
 }
 
-static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
        if (cfs_rq->last == se)
                cfs_rq->last = NULL;
@@ -728,6 +728,12 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
                cfs_rq->next = NULL;
 }
 
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+       for_each_sched_entity(se)
+               __clear_buddies(cfs_rq_of(se), se);
+}
+
 static void
 dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
@@ -768,8 +774,14 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 
        ideal_runtime = sched_slice(cfs_rq, curr);
        delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
-       if (delta_exec > ideal_runtime)
+       if (delta_exec > ideal_runtime) {
                resched_task(rq_of(cfs_rq)->curr);
+               /*
+                * The current task ran long enough, ensure it doesn't get
+                * re-elected due to buddy favours.
+                */
+               clear_buddies(cfs_rq, curr);
+       }
 }
 
 static void
@@ -1445,6 +1457,11 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
 
        do {
                se = pick_next_entity(cfs_rq);
+               /*
+                * If se was a buddy, clear it so that it will have to earn
+                * the favour again.
+                */
+               __clear_buddies(cfs_rq, se);
                set_next_entity(cfs_rq, se);
                cfs_rq = group_cfs_rq(se);
        } while (cfs_rq);