diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f5e1e6f96411..e506d9de16fc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5443,6 +5443,15 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) put_prev_task_balance(rq, prev, rf); smt_mask = cpu_smt_mask(cpu); + need_sync = !!rq->core->core_cookie; + + /* reset state */ + rq->core->core_cookie = 0UL; + if (rq->core->core_forceidle) { + need_sync = true; + fi_before = true; + rq->core->core_forceidle = false; + } /* * core->core_task_seq, core->core_pick_seq, rq->core_sched_seq @@ -5455,14 +5464,25 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) * 'Fix' this by also increasing @task_seq for every pick. */ rq->core->core_task_seq++; - need_sync = !!rq->core->core_cookie; - /* reset state */ - rq->core->core_cookie = 0UL; - if (rq->core->core_forceidle) { + /* + * Optimize for common case where this CPU has no cookies + * and there are no cookied tasks running on siblings. + */ + if (!need_sync) { + for_each_class(class) { + next = class->pick_task(rq); + if (next) + break; + } + + if (!next->core_cookie) { + rq->core_pick = NULL; + goto done; + } need_sync = true; - rq->core->core_forceidle = false; } + for_each_cpu(i, smt_mask) { struct rq *rq_i = cpu_rq(i); @@ -5492,31 +5512,8 @@ again: * core. */ p = pick_task(rq_i, class, max); - if (!p) { - /* - * If there weren't no cookies; we don't need to - * bother with the other siblings. - * If the rest of the core is not running a tagged - * task, i.e. need_sync == 0, and the current CPU - * which called into the schedule() loop does not - * have any tasks for this class, skip selecting for - * other siblings since there's no point. We don't skip - * for RT/DL because that could make CFS force-idle RT. - */ - if (i == cpu && !need_sync && class == &fair_sched_class) - goto next_class; - + if (!p) continue; - } - - /* - * Optimize the 'normal' case where there aren't any - * cookies and we don't need to sync up. - */ - if (i == cpu && !need_sync && !p->core_cookie) { - next = p; - goto done; - } rq_i->core_pick = p; @@ -5544,19 +5541,9 @@ again: cpu_rq(j)->core_pick = NULL; } goto again; - } else { - /* - * Once we select a task for a cpu, we - * should not be doing an unconstrained - * pick because it might starve a task - * on a forced idle cpu. - */ - need_sync = true; } - } } -next_class:; } rq->core->core_pick_seq = rq->core->core_task_seq;