1 files changed, 16 insertions, 5 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 47a0c552c77b..396bca9c7996 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5794,27 +5794,38 @@ static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd
 static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
 {
         struct sched_domain *this_sd;
-        u64 avg_cost, avg_idle = this_rq()->avg_idle;
+        u64 avg_cost, avg_idle;
         u64 time, cost;
         s64 delta;
-        int cpu;
+        int cpu, nr = INT_MAX;
 
         this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
         if (!this_sd)
                 return -1;
 
-        avg_cost = this_sd->avg_scan_cost;
-
         /*
          * Due to large variance we need a large fuzz factor; hackbench in
          * particularly is sensitive here.
          */
-        if (sched_feat(SIS_AVG_CPU) && (avg_idle / 512) < avg_cost)
+        avg_idle = this_rq()->avg_idle / 512;
+        avg_cost = this_sd->avg_scan_cost + 1;
+
+        if (sched_feat(SIS_AVG_CPU) && avg_idle < avg_cost)
                 return -1;
 
+        if (sched_feat(SIS_PROP)) {
+                u64 span_avg = sd->span_weight * avg_idle;
+                if (span_avg > 4*avg_cost)
+                        nr = div_u64(span_avg, avg_cost);
+                else
+                        nr = 4;
+        }
+
         time = local_clock();
 
         for_each_cpu_wrap(cpu, sched_domain_span(sd), target) {
+                if (!--nr)
+                        return -1;
                 if (!cpumask_test_cpu(cpu, &p->cpus_allowed))
                         continue;
                 if (idle_cpu(cpu))