sched/fair: Add some serialization to the sched_domain load-balance walk

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

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 968ffee..cf86f74 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3828,7 +3828,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
         */
        if (local_group) {
                if (idle != CPU_NEWLY_IDLE) {
-                       if (balance_cpu != this_cpu) {
+                       if (balance_cpu != this_cpu ||
+                           cmpxchg(&group->balance_cpu, -1, balance_cpu) != -1) {
                                *balance = 0;
                                return;
                        }
@@ -4929,7 +4930,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
        int balance = 1;
        struct rq *rq = cpu_rq(cpu);
        unsigned long interval;
-       struct sched_domain *sd;
+       struct sched_domain *sd, *last = NULL;
        /* Earliest time when we have to do rebalance again */
        unsigned long next_balance = jiffies + 60*HZ;
        int update_next_balance = 0;
@@ -4939,6 +4940,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
 
        rcu_read_lock();
        for_each_domain(cpu, sd) {
+               last = sd;
                if (!(sd->flags & SD_LOAD_BALANCE))
                        continue;
 
@@ -4983,6 +4985,9 @@ out:
                if (!balance)
                        break;
        }
+       for (sd = last; sd; sd = sd->child)
+               (void)cmpxchg(&sd->groups->balance_cpu, cpu, -1);
+
        rcu_read_unlock();
 
        /*