sched/fair: Optimize select_idle_cpu

[linux.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 08a233e97a01974850ddeac7b7ccd6b782ea897b..280d54ccb4bed6503a22b267a996a812d4432304 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5828,6 +5828,7 @@ static inline int select_idle_smt(struct task_struct *p, int target)
  */
 static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
 {
+       struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
        struct sched_domain *this_sd;
        u64 avg_cost, avg_idle;
        u64 time, cost;
@@ -5859,11 +5860,11 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
 
        time = cpu_clock(this);
 
-       for_each_cpu_wrap(cpu, sched_domain_span(sd), target) {
+       cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+       for_each_cpu_wrap(cpu, cpus, target) {
                if (!--nr)
                        return si_cpu;
-               if (!cpumask_test_cpu(cpu, p->cpus_ptr))
-                       continue;
                if (available_idle_cpu(cpu))
                        break;
                if (si_cpu == -1 && sched_idle_cpu(cpu))
@@ -10322,6 +10323,9 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
        if (!task_on_rq_queued(p))
                return;
 
+       if (rq->cfs.nr_running == 1)
+               return;
+
        /*
         * Reschedule if we are currently running on this runqueue and
         * our priority decreased, or if we are not currently running on