Messages in this thread Patch in this message | | | Date | Fri, 12 Nov 2021 15:55:27 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/2] sched/fair: skip newidle update stats |
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Subject: sched/fair: Reflow newidle_balance() From: Peter Zijlstra <peterz@infradead.org> Date: Fri Nov 12 15:46:08 CET 2021
The control flow in newidle_balance() is a little convoluted, attempt simplification.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/fair.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-)
--- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10858,10 +10858,10 @@ static inline void nohz_newidle_balance( static int newidle_balance(struct rq *this_rq, struct rq_flags *rf) { unsigned long next_balance = jiffies + HZ; + int pulled_task = 0, timeout = 0; int this_cpu = this_rq->cpu; u64 t0, t1, curr_cost = 0; struct sched_domain *sd; - int pulled_task = 0, early_stop = 0; update_misfit_status(NULL, this_rq); @@ -10889,17 +10889,9 @@ static int newidle_balance(struct rq *th if (!READ_ONCE(this_rq->rd->overload) || (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) { - if (sd) { + if (sd) update_next_balance(sd, &next_balance); - /* - * We skip new idle LB because there is not enough - * time before next wake up. Make sure that we will - * not kick NOHZ_NEWILB_KICK - */ - early_stop = 1; - } - goto out; } @@ -10922,7 +10914,7 @@ static int newidle_balance(struct rq *th update_next_balance(sd, &next_balance); if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) { - early_stop = 1; + timeout = 1; break; } @@ -10967,6 +10959,11 @@ static int newidle_balance(struct rq *th if (this_rq->nr_running != this_rq->cfs.h_nr_running) pulled_task = -1; + if (pulled_task || timeout) + goto out; + + nohz_newidle_balance(this_rq); + out: /* Move the next balance forward */ if (time_after(this_rq->next_balance, next_balance)) @@ -10974,8 +10971,6 @@ static int newidle_balance(struct rq *th if (pulled_task) this_rq->idle_stamp = 0; - else if (!early_stop) - nohz_newidle_balance(this_rq); return pulled_task; }
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