sched/balancing: Fix 'local->avg_load > busiest->avg_load' case in fix_small_imbalance()

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9b3fe1c..2aedacc 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4823,8 +4823,8 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
                (busiest->load_per_task * SCHED_POWER_SCALE) /
                busiest->group_power;
 
-       if (busiest->avg_load - local->avg_load + scaled_busy_load_per_task >=
-           (scaled_busy_load_per_task * imbn)) {
+       if (busiest->avg_load + scaled_busy_load_per_task >=
+           local->avg_load + (scaled_busy_load_per_task * imbn)) {
                env->imbalance = busiest->load_per_task;
                return;
        }
@@ -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);
        }
@@ -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);