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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-01-25 21:08:31 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-25 21:08:31 +0100
commit48d5e258216f1c7713633439beb98a38c7290649 (patch)
tree6f8c98785015d56337e87ed56b23d39feeeaf846 /kernel
parent614ee1f61f667b02165c1ae0c1357048dc6d94a0 (diff)
sched: rt throttling vs no_hz
We need to teach no_hz about the rt throttling because its tick driven. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c23
-rw-r--r--kernel/sched_rt.c30
-rw-r--r--kernel/time/tick-sched.c5
3 files changed, 43 insertions, 15 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 5ea2c533b43..22712b2e058 100644
--- 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;
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 1144bf55669..8bfdb3f8a52 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -175,7 +175,11 @@ static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq)
ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
if (rt_rq->rt_time > ratio) {
+ struct rq *rq = rq_of_rt_rq(rt_rq);
+
+ rq->rt_throttled = 1;
rt_rq->rt_throttled = 1;
+
sched_rt_ratio_dequeue(rt_rq);
return 1;
}
@@ -183,18 +187,6 @@ static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq)
return 0;
}
-static void __update_sched_rt_period(struct rt_rq *rt_rq, u64 period)
-{
- unsigned long rt_ratio = sched_rt_ratio(rt_rq);
- u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
-
- rt_rq->rt_time -= min(rt_rq->rt_time, ratio);
- if (rt_rq->rt_throttled) {
- rt_rq->rt_throttled = 0;
- sched_rt_ratio_enqueue(rt_rq);
- }
-}
-
static void update_sched_rt_period(struct rq *rq)
{
struct rt_rq *rt_rq;
@@ -204,8 +196,18 @@ static void update_sched_rt_period(struct rq *rq)
period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
rq->rt_period_expire += period;
- for_each_leaf_rt_rq(rt_rq, rq)
- __update_sched_rt_period(rt_rq, period);
+ for_each_leaf_rt_rq(rt_rq, rq) {
+ unsigned long rt_ratio = sched_rt_ratio(rt_rq);
+ u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+
+ rt_rq->rt_time -= min(rt_rq->rt_time, ratio);
+ if (rt_rq->rt_throttled) {
+ rt_rq->rt_throttled = 0;
+ sched_rt_ratio_enqueue(rt_rq);
+ }
+ }
+
+ rq->rt_throttled = 0;
}
}
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index cb89fa8db11..5f9fb645b72 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -153,6 +153,7 @@ void tick_nohz_update_jiffies(void)
void tick_nohz_stop_sched_tick(void)
{
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
+ unsigned long rt_jiffies;
struct tick_sched *ts;
ktime_t last_update, expires, now, delta;
struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
@@ -216,6 +217,10 @@ void tick_nohz_stop_sched_tick(void)
next_jiffies = get_next_timer_interrupt(last_jiffies);
delta_jiffies = next_jiffies - last_jiffies;
+ rt_jiffies = rt_needs_cpu(cpu);
+ if (rt_jiffies && rt_jiffies < delta_jiffies)
+ delta_jiffies = rt_jiffies;
+
if (rcu_needs_cpu(cpu))
delta_jiffies = 1;
/*