Messages in this thread |  | | Date | Sat, 3 Dec 2022 14:33:23 +0000 | From | Qais Yousef <> | Subject | Re: [RFC PATCH 3/3] sched/fair: Traverse cpufreq policies to detect capacity inversion |
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On 12/02/22 15:57, Vincent Guittot wrote:
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 7c0dd57e562a..4bbbca85134b 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -8856,23 +8856,20 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) > > * * Thermal pressure will impact all cpus in this perf domain > > * equally. > > */ > > - if (sched_energy_enabled()) { > > + if (static_branch_unlikely(&sched_asym_cpucapacity)) { > > unsigned long inv_cap = capacity_orig - thermal_load_avg(rq); > > - struct perf_domain *pd = rcu_dereference(rq->rd->pd); > > + struct cpufreq_policy *policy, __maybe_unused *policy_n; > > > > rq->cpu_capacity_inverted = 0; > > > > - SCHED_WARN_ON(!rcu_read_lock_held()); > > - > > - for (; pd; pd = pd->next) { > > - struct cpumask *pd_span = perf_domain_span(pd); > > + for_each_active_policy_safe(policy, policy_n) { > > So you are looping all cpufreq policy (and before the perf domain) in > the period load balance. That' really not something we should or want > to do
Why is it not acceptable in the period load balance but acceptable in the hot wake up path in feec()? What's the difference?
Thanks!
-- Qais Yousef
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