Messages in this thread | | | From | Josh Don <> | Date | Mon, 27 Jun 2022 16:42:49 -0700 | Subject | Re: [PATCH v4 4/7] sched/fair: remove useless check in select_idle_core |
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On Sun, Jun 19, 2022 at 5:05 AM Abel Wu <wuyun.abel@bytedance.com> wrote: > > The function only gets called when sds->has_idle_cores is true which can > be possible only when sched_smt_present is enabled. > > Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> > --- > kernel/sched/fair.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index aba1dad19574..1cc86e76e38e 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6256,9 +6256,6 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu > bool idle = true; > int cpu; > > - if (!static_branch_likely(&sched_smt_present)) > - return __select_idle_cpu(core, p); > -
The static branch is basically free; although you're right that we currently don't take !smt_present branch direction here, it doesn't seem harmful to leave this check in case assumptions change about when we call select_idle_core().
> for_each_cpu(cpu, cpu_smt_mask(core)) { > if (!available_idle_cpu(cpu)) { > idle = false; > -- > 2.31.1 >
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