diff --git a/include/linux/sched.h b/include/linux/sched.h index 07576479c0ed..bb436ee1942d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -685,20 +685,22 @@ struct sched_dl_entity { * * @dl_server tells if this is a server entity. * - * @dl_defer tells if this is a deferred or regular server. For - * now only defer server exists. - * - * @dl_defer_armed tells if the deferrable server is waiting - * for the replenishment timer to activate it. - * * @dl_server_active tells if the dlserver is active(started). * dlserver is started on first cfs enqueue on an idle runqueue * and is stopped when a dequeue results in 0 cfs tasks on the * runqueue. In other words, dlserver is active only when cpu's * runqueue has atleast one cfs task. * + * @dl_defer tells if this is a deferred or regular server. For + * now only defer server exists. + * + * @dl_defer_armed tells if the deferrable server is waiting + * for the replenishment timer to activate it. + * * @dl_defer_running tells if the deferrable server is actually * running, skipping the defer phase. + * + * @dl_defer_idle tracks idle state */ unsigned int dl_throttled : 1; unsigned int dl_yielded : 1; @@ -709,6 +711,7 @@ struct sched_dl_entity { unsigned int dl_defer : 1; unsigned int dl_defer_armed : 1; unsigned int dl_defer_running : 1; + unsigned int dl_defer_idle : 1; /* * Bandwidth enforcement timer. Each -deadline task has its diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ece25caf379c..8307f24b8900 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1173,6 +1173,11 @@ static enum hrtimer_restart dl_server_timer(struct hrtimer *timer, struct sched_ */ rq->donor->sched_class->update_curr(rq); + if (dl_se->dl_defer_idle) { + dl_server_stop(dl_se); + return HRTIMER_NORESTART; + } + if (dl_se->dl_defer_armed) { /* * First check if the server could consume runtime in background. @@ -1420,10 +1425,11 @@ s64 dl_scaled_delta_exec(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta } static inline void -update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, - int flags); +update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se, int flags); + static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 delta_exec) { + bool idle = rq->curr == rq->idle; s64 scaled_delta_exec; if (unlikely(delta_exec <= 0)) { @@ -1444,6 +1450,9 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 dl_se->runtime -= scaled_delta_exec; + if (dl_se->dl_defer_idle && !idle) + dl_se->dl_defer_idle = 0; + /* * The fair server can consume its runtime while throttled (not queued/ * running as regular CFS). @@ -1453,6 +1462,29 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 * starting a new period, pushing the activation. */ if (dl_se->dl_defer && dl_se->dl_throttled && dl_runtime_exceeded(dl_se)) { + /* + * Non-servers would never get time accounted while throttled. + */ + WARN_ON_ONCE(!dl_server(dl_se)); + + /* + * While the server is marked idle, do not push out the + * activation further, instead wait for the period timer + * to lapse and stop the server. + */ + if (dl_se->dl_defer_idle && idle) { + /* + * The timer is at the zero-laxity point, this means + * dl_server_stop() / dl_server_start() can happen + * while now < deadline. This means update_dl_entity() + * will not replenish. Additionally start_dl_timer() + * will be set for 'deadline - runtime'. Negative + * runtime will not do. + */ + dl_se->runtime = 0; + return; + } + /* * If the server was previously activated - the starving condition * took place, it this point it went away because the fair scheduler @@ -1465,6 +1497,9 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 replenish_dl_new_period(dl_se, dl_se->rq); + if (idle) + dl_se->dl_defer_idle = 1; + /* * Not being able to start the timer seems problematic. If it could not * be started for whatever reason, we need to "unthrottle" the DL server @@ -1590,6 +1625,7 @@ void dl_server_stop(struct sched_dl_entity *dl_se) hrtimer_try_to_cancel(&dl_se->dl_timer); dl_se->dl_defer_armed = 0; dl_se->dl_throttled = 0; + dl_se->dl_defer_idle = 0; dl_se->dl_server_active = 0; }