Messages in this thread | | | From | Dietmar Eggemann <> | Subject | Re: [PATCH v2 8/9] sched/fair: Split select_task_rq_fair want_affine logic | Date | Thu, 19 Mar 2020 11:30:08 +0100 |
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On 11.03.20 19:16, Valentin Schneider wrote:
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> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index f98dac0c7f82..a6fca6817e92 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6620,26 +6620,33 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags) > } > > rcu_read_lock(); > + > + sd = highest_flag_domain(cpu, sd_flag); > + > + /* > + * If !want_affine, we just look for the highest domain where > + * sd_flag is set. > + */ > + if (!want_affine) > + goto scan; > + > + /* > + * Otherwise we look for the lowest domain with SD_WAKE_AFFINE and that > + * spans both 'cpu' and 'prev_cpu'. > + */ > for_each_domain(cpu, tmp) { > - /* > - * If both 'cpu' and 'prev_cpu' are part of this domain, > - * cpu is a valid SD_WAKE_AFFINE target. > - */ > - if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && > + if ((tmp->flags & SD_WAKE_AFFINE) && > cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { > if (cpu != prev_cpu) > new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync); > > - sd = NULL; /* Prefer wake_affine over balance flags */ > + /* Prefer wake_affine over SD lookup */
I assume that 'balance flags' stands for (wakeup) load balance, i.e. find_idlest_xxx() path. So why change it?
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