sched: rt-group: reduce rescheduling

[linux-2.6] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 5ea2c533b43244c509db38adf29c4b5847729b1c..22712b2e058a45f82f01f65ccb89c61117ccaa37 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -442,6 +442,7 @@ struct rq {
        struct cfs_rq cfs;
        struct rt_rq rt;
        u64 rt_period_expire;
+       int rt_throttled;
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
        /* list of leaf cfs_rq on this cpu: */
@@ -594,6 +595,23 @@ static void update_rq_clock(struct rq *rq)
 #define task_rq(p)             cpu_rq(task_cpu(p))
 #define cpu_curr(cpu)          (cpu_rq(cpu)->curr)
 
+unsigned long rt_needs_cpu(int cpu)
+{
+       struct rq *rq = cpu_rq(cpu);
+       u64 delta;
+
+       if (!rq->rt_throttled)
+               return 0;
+
+       if (rq->clock > rq->rt_period_expire)
+               return 1;
+
+       delta = rq->rt_period_expire - rq->clock;
+       do_div(delta, NSEC_PER_SEC / HZ);
+
+       return (unsigned long)delta;
+}
+
 /*
  * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
  */
@@ -7102,9 +7120,11 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
        /* delimiter for bitsearch: */
        __set_bit(MAX_RT_PRIO, array->bitmap);
 
+#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+       rt_rq->highest_prio = MAX_RT_PRIO;
+#endif
 #ifdef CONFIG_SMP
        rt_rq->rt_nr_migratory = 0;
-       rt_rq->highest_prio = MAX_RT_PRIO;
        rt_rq->overloaded = 0;
 #endif
 
@@ -7191,6 +7211,7 @@ void __init sched_init(void)
                                &per_cpu(init_sched_rt_entity, i), i, 1);
 #endif
                rq->rt_period_expire = 0;
+               rq->rt_throttled = 0;
 
                for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
                        rq->cpu_load[j] = 0;