sched: rt-group: fixup schedulability constraints calculation
it was only possible to configure the rt-group scheduling parameters
beyond the default value in a very small range.
that's because div64_64() has a different calling convention than
do_div() :/
fix a few untidies while we are here; sysctl_sched_rt_period may overflow
due to that multiplication, so cast to u64 first. Also that RUNTIME_INF
juggling makes little sense although its an effective NOP.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 5b13e4b..b8ee864 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7726,9 +7726,7 @@
if (runtime == RUNTIME_INF)
return 1ULL << 16;
- runtime *= (1ULL << 16);
- div64_64(runtime, period);
- return runtime;
+ return div64_64(runtime << 16, period);
}
static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
@@ -7757,18 +7755,16 @@
u64 rt_runtime, rt_period;
int err = 0;
- rt_period = sysctl_sched_rt_period * NSEC_PER_USEC;
+ rt_period = (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
if (rt_runtime_us == -1)
- rt_runtime = rt_period;
+ rt_runtime = RUNTIME_INF;
mutex_lock(&rt_constraints_mutex);
if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
err = -EINVAL;
goto unlock;
}
- if (rt_runtime_us == -1)
- rt_runtime = RUNTIME_INF;
tg->rt_runtime = rt_runtime;
unlock:
mutex_unlock(&rt_constraints_mutex);
