sched: fix improper load balance across sched domain

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

diff --git a/kernel/sched.c b/kernel/sched.c
index 5e220bf..9754364 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2336,7 +2336,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
        unsigned long max_pull;
        unsigned long busiest_load_per_task, busiest_nr_running;
        unsigned long this_load_per_task, this_nr_running;
-       int load_idx;
+       int load_idx, group_imb = 0;
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
        int power_savings_balance = 1;
        unsigned long leader_nr_running = 0, min_load_per_task = 0;
@@ -2355,9 +2355,10 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
                load_idx = sd->idle_idx;
 
        do {
-               unsigned long load, group_capacity;
+               unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
                int local_group;
                int i;
+               int __group_imb = 0;
                unsigned int balance_cpu = -1, first_idle_cpu = 0;
                unsigned long sum_nr_running, sum_weighted_load;
 
@@ -2368,6 +2369,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
 
                /* Tally up the load of all CPUs in the group */
                sum_weighted_load = sum_nr_running = avg_load = 0;
+               max_cpu_load = 0;
+               min_cpu_load = ~0UL;
 
                for_each_cpu_mask(i, group->cpumask) {
                        struct rq *rq;
@@ -2388,8 +2391,13 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
                                }
 
                                load = target_load(i, load_idx);
-                       } else
+                       } else {
                                load = source_load(i, load_idx);
+                               if (load > max_cpu_load)
+                                       max_cpu_load = load;
+                               if (min_cpu_load > load)
+                                       min_cpu_load = load;
+                       }
 
                        avg_load += load;
                        sum_nr_running += rq->nr_running;
@@ -2415,6 +2423,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
                avg_load = sg_div_cpu_power(group,
                                avg_load * SCHED_LOAD_SCALE);
 
+               if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE)
+                       __group_imb = 1;
+
                group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
 
                if (local_group) {
@@ -2423,11 +2434,12 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
                        this_nr_running = sum_nr_running;
                        this_load_per_task = sum_weighted_load;
                } else if (avg_load > max_load &&
-                          sum_nr_running > group_capacity) {
+                          (sum_nr_running > group_capacity || __group_imb)) {
                        max_load = avg_load;
                        busiest = group;
                        busiest_nr_running = sum_nr_running;
                        busiest_load_per_task = sum_weighted_load;
+                       group_imb = __group_imb;
                }
 
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
@@ -2499,6 +2511,9 @@ group_next:
                goto out_balanced;
 
        busiest_load_per_task /= busiest_nr_running;
+       if (group_imb)
+               busiest_load_per_task = min(busiest_load_per_task, avg_load);
+
        /*
         * We're trying to get all the cpus to the average_load, so we don't
         * want to push ourselves above the average load, nor do we wish to