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sched: rt: fix SMP bandwidth balancing for throttled groups 

Now we exceed the runtime and get throttled - the period rollover tick
will subtract the cpu quota from the runtime and check if we're below
quota. However with this cpu having a very small portion of the runtime
it will not refresh as fast as it should.

Therefore, also rebalance the runtime when we're throttled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Daniel K." <dk@uw.no>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Peter Zijlstra 2008-06-19 14:22:25 +02:00 committed by Ingo Molnar
parent ada18de2eb
commit b79f3833d8
1 changed files with 29 additions and 12 deletions
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41
kernel/sched_rt.c
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@ -228,6 +228,28 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
#endif
#ifdef CONFIG_SMP
static int do_balance_runtime(struct rt_rq *rt_rq);
static int balance_runtime(struct rt_rq *rt_rq)
{
int more = 0;
if (rt_rq->rt_time > rt_rq->rt_runtime) {
spin_unlock(&rt_rq->rt_runtime_lock);
more = do_balance_runtime(rt_rq);
spin_lock(&rt_rq->rt_runtime_lock);
}
return more;
}
#else
static inline int balance_runtime(struct rt_rq *rt_rq)
{
return 0;
}
#endif
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
{
int i, idle = 1;
@ -247,6 +269,8 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
u64 runtime;
spin_lock(&rt_rq->rt_runtime_lock);
if (rt_rq->rt_throttled)
balance_runtime(rt_rq);
runtime = rt_rq->rt_runtime;
rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
@ -267,7 +291,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
}
#ifdef CONFIG_SMP
static int balance_runtime(struct rt_rq *rt_rq)
static int do_balance_runtime(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
@ -428,17 +452,10 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
return 0;
#ifdef CONFIG_SMP
if (rt_rq->rt_time > runtime) {
spin_unlock(&rt_rq->rt_runtime_lock);
balance_runtime(rt_rq);
spin_lock(&rt_rq->rt_runtime_lock);
runtime = sched_rt_runtime(rt_rq);
if (runtime == RUNTIME_INF)
return 0;
}
#endif
balance_runtime(rt_rq);
runtime = sched_rt_runtime(rt_rq);
if (runtime == RUNTIME_INF)
return 0;
if (rt_rq->rt_time > runtime) {
rt_rq->rt_throttled = 1;