1 files changed, 31 insertions, 3 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index a757f6b11cbd..132950b33dde 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -460,7 +460,7 @@ struct rq {
         unsigned long last_load_update_tick;
 #ifdef CONFIG_NO_HZ
         u64 nohz_stamp;
-        unsigned char in_nohz_recently;
+        unsigned char nohz_balance_kick;
 #endif
         unsigned int skip_clock_update;
 
@@ -1195,6 +1195,27 @@ static void resched_cpu(int cpu)
 
 #ifdef CONFIG_NO_HZ
 /*
+ * In the semi idle case, use the nearest busy cpu for migrating timers
+ * from an idle cpu.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle cpu will add more delays to the timers than intended
+ * (as that cpu's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+        int cpu = smp_processor_id();
+        int i;
+        struct sched_domain *sd;
+
+        for_each_domain(cpu, sd) {
+                for_each_cpu(i, sched_domain_span(sd))
+                        if (!idle_cpu(i))
+                                return i;
+        }
+        return cpu;
+}
+/*
  * When add_timer_on() enqueues a timer into the timer wheel of an
  * idle CPU then this timer might expire before the next timer event
  * which is scheduled to wake up that CPU. In case of a completely
@@ -7791,6 +7812,10 @@ void __init sched_init(void)
                 rq->idle_stamp = 0;
                 rq->avg_idle = 2*sysctl_sched_migration_cost;
                 rq_attach_root(rq, &def_root_domain);
+#ifdef CONFIG_NO_HZ
+                rq->nohz_balance_kick = 0;
+                init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb, i));
+#endif
 #endif
                 init_rq_hrtick(rq);
                 atomic_set(&rq->nr_iowait, 0);
@@ -7835,8 +7860,11 @@ void __init sched_init(void)
         zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
 #ifdef CONFIG_SMP
 #ifdef CONFIG_NO_HZ
-        zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
-        alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
+        zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+        alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT);
+        atomic_set(&nohz.load_balancer, nr_cpu_ids);
+        atomic_set(&nohz.first_pick_cpu, nr_cpu_ids);
+        atomic_set(&nohz.second_pick_cpu, nr_cpu_ids);
 #endif
         /* May be allocated at isolcpus cmdline parse time */
         if (cpu_isolated_map == NULL)