On Thu, 6 Mar 2014 13:20:40 +0100 Juri Lelli <juri.le...@gmail.com> wrote:
> Yes. I think you can go with > > p->prio = p->normal_prio > > and save a few checks in rt_mutex_getprio(). > You're right! Thanks. ----- I decided to run my tests on linux-next, and my wakeup_rt tracer was broken. After running a bisect, I found that the problem commit was: linux-next commit c365c292d059 "sched: Consider pi boosting in setscheduler()" And the reason the wake_rt tracer test was failing, was because it had no RT task to trace. I first noticed this when running with sched_switch event and saw that my RT task still had normal SCHED_OTHER priority. Looking at the problem commit, I found: - p->normal_prio = normal_prio(p); - p->prio = rt_mutex_getprio(p); With no + p->normal_prio = normal_prio(p); + p->prio = rt_mutex_getprio(p); Reading what the commit is suppose to do, I realize that the p->prio can't be set if the task is boosted with a higher prio, but the p->normal_prio still needs to be set regardless, otherwise, when the task is deboosted, it wont get the new priority. The p->prio has to be set before "check_class_changed()" is called, otherwise the class wont be changed. Link: http://lkml.kernel.org/r/20140305232931.449ee...@gandalf.local.home Signed-off-by: Steven Rostedt <rost...@goodmis.org> --- kernel/sched/core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4600bca..3134756 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3198,6 +3198,7 @@ static void __setscheduler_params(struct task_struct *p, * getparam()/getattr() don't report silly values for !rt tasks. */ p->rt_priority = attr->sched_priority; + p->normal_prio = normal_prio(p); set_load_weight(p); } @@ -3207,6 +3208,12 @@ static void __setscheduler(struct rq *rq, struct task_struct *p, { __setscheduler_params(p, attr); + /* + * If we get here, there was no pi waiters boosting the + * task. It is safe to use the normal prio. + */ + p->prio = normal_prio(p); + if (dl_prio(p->prio)) p->sched_class = &dl_sched_class; else if (rt_prio(p->prio)) -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
