sched/balancing: Fix 'local->avg_load > sds->avg_load' case in calculate_imbalance()

[linux-drm-fsl-dcu.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7f0a5e6cdae0e03db16a8c8fec5bd48ba1f893af..0b99aae339cb90fca133b234a836f1cf915fc06a 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4896,7 +4896,8 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
         * max load less than avg load(as we skip the groups at or below
         * its cpu_power, while calculating max_load..)
         */
-       if (busiest->avg_load < sds->avg_load) {
+       if (busiest->avg_load <= sds->avg_load ||
+           local->avg_load >= sds->avg_load) {
                env->imbalance = 0;
                return fix_small_imbalance(env, sds);
        }
@@ -5151,7 +5152,7 @@ static int should_we_balance(struct lb_env *env)
         * First idle cpu or the first cpu(busiest) in this sched group
         * is eligible for doing load balancing at this and above domains.
         */
-       return balance_cpu != env->dst_cpu;
+       return balance_cpu == env->dst_cpu;
 }
 
 /*
@@ -5928,11 +5929,15 @@ static void task_fork_fair(struct task_struct *p)
        cfs_rq = task_cfs_rq(current);
        curr = cfs_rq->curr;
 
-       if (unlikely(task_cpu(p) != this_cpu)) {
-               rcu_read_lock();
-               __set_task_cpu(p, this_cpu);
-               rcu_read_unlock();
-       }
+       /*
+        * Not only the cpu but also the task_group of the parent might have
+        * been changed after parent->se.parent,cfs_rq were copied to
+        * child->se.parent,cfs_rq. So call __set_task_cpu() to make those
+        * of child point to valid ones.
+        */
+       rcu_read_lock();
+       __set_task_cpu(p, this_cpu);
+       rcu_read_unlock();
 
        update_curr(cfs_rq);