From: Peter Zijlstra Date: Wed, 27 Feb 2008 11:00:46 +0000 (+0100) Subject: sched: rt-group: fixup schedulability constraints calculation X-Git-Tag: v2.6.25-rc5~13^2~1 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2692a2406b9262bbb101708815be99ec2988e48b;p=linux-2.6 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 Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched.c b/kernel/sched.c index 5b13e4b0e0..b8ee864c74 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7726,9 +7726,7 @@ static unsigned long to_ratio(u64 period, u64 runtime) 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 @@ int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 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);