Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler changes for v3.4 from Ingo Molnar

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  printk: Make it compile with !CONFIG_PRINTK
  sched/x86: Fix overflow in cyc2ns_offset
  sched: Fix nohz load accounting -- again!
  sched: Update yield() docs
  printk/sched: Introduce special printk_sched() for those awkward moments
  sched/nohz: Correctly initialize 'next_balance' in 'nohz' idle balancer
  sched: Cleanup cpu_active madness
  sched: Fix load-balance wreckage
  sched: Clean up parameter passing of proc_sched_autogroup_set_nice()
  sched: Ditch per cgroup task lists for load-balancing
  sched: Rename load-balancing fields
  sched: Move load-balancing arguments into helper struct
  sched/rt: Do not submit new work when PI-blocked
  sched/rt: Prevent idle task boosting
  sched/wait: Add __wake_up_all_locked() API
  sched/rt: Document scheduler related skip-resched-check sites
  sched/rt: Use schedule_preempt_disabled()
  sched/rt: Add schedule_preempt_disabled()
  sched/rt: Do not throttle when PI boosting
  sched/rt: Keep period timer ticking when rt throttling is active
  ...

1 files changed, 34 insertions, 9 deletions

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index f42ae7f..b60dad7 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -778,12 +778,9 @@ static inline int balance_runtime(struct rt_rq *rt_rq)
 
 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 {
-	int i, idle = 1;
+	int i, idle = 1, throttled = 0;
 	const struct cpumask *span;
 
-	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
-		return 1;
-
 	span = sched_rt_period_mask();
 	for_each_cpu(i, span) {
 		int enqueue = 0;
@@ -818,12 +815,17 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 			if (!rt_rq_throttled(rt_rq))
 				enqueue = 1;
 		}
+		if (rt_rq->rt_throttled)
+			throttled = 1;
 
 		if (enqueue)
 			sched_rt_rq_enqueue(rt_rq);
 		raw_spin_unlock(&rq->lock);
 	}
 
+	if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
+		return 1;
+
 	return idle;
 }
 
@@ -855,8 +857,30 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 		return 0;
 
 	if (rt_rq->rt_time > runtime) {
-		rt_rq->rt_throttled = 1;
-		printk_once(KERN_WARNING "sched: RT throttling activated\n");
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+		/*
+		 * Don't actually throttle groups that have no runtime assigned
+		 * but accrue some time due to boosting.
+		 */
+		if (likely(rt_b->rt_runtime)) {
+			static bool once = false;
+
+			rt_rq->rt_throttled = 1;
+
+			if (!once) {
+				once = true;
+				printk_sched("sched: RT throttling activated\n");
+			}
+		} else {
+			/*
+			 * In case we did anyway, make it go away,
+			 * replenishment is a joke, since it will replenish us
+			 * with exactly 0 ns.
+			 */
+			rt_rq->rt_time = 0;
+		}
+
 		if (rt_rq_throttled(rt_rq)) {
 			sched_rt_rq_dequeue(rt_rq);
 			return 1;
@@ -884,7 +908,8 @@ static void update_curr_rt(struct rq *rq)
 	if (unlikely((s64)delta_exec < 0))
 		delta_exec = 0;
 
-	schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
+	schedstat_set(curr->se.statistics.exec_max,
+		      max(curr->se.statistics.exec_max, delta_exec));
 
 	curr->se.sum_exec_runtime += delta_exec;
 	account_group_exec_runtime(curr, delta_exec);
@@ -1972,7 +1997,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
 	if (--p->rt.time_slice)
 		return;
 
-	p->rt.time_slice = DEF_TIMESLICE;
+	p->rt.time_slice = RR_TIMESLICE;
 
 	/*
 	 * Requeue to the end of queue if we are not the only element
@@ -2000,7 +2025,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
 	 * Time slice is 0 for SCHED_FIFO tasks
 	 */
 	if (task->policy == SCHED_RR)
-		return DEF_TIMESLICE;
+		return RR_TIMESLICE;
 	else
 		return 0;
 }