From: Peter Zijlstra Date: Tue, 18 Oct 2011 20:03:48 +0000 (+0200) Subject: sched/rt: Do not throttle when PI boosting X-Git-Tag: v3.4-rc1~3^2~28 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7abc63b1bd412f7655b62ef3e35c3c11c5134636;p=platform%2Fkernel%2Flinux-3.10.git sched/rt: Do not throttle when PI boosting When a runqueue has rt_runtime_us = 0 then the only way it can accumulate rt_time is via PI boosting. That causes the runqueue to be throttled and replenishing does not change anything due to rt_runtime_us = 0. So avoid that situation by clearing rt_time and skip the throttling alltogether. Signed-off-by: Peter Zijlstra [ Changelog ] Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/n/tip-7x70cypsotjb4jvcor3edctk@git.kernel.org Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 6d1eb0b..7f7e7cd 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -857,8 +857,24 @@ 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)) { + rt_rq->rt_throttled = 1; + printk_once(KERN_WARNING "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;