On Fri, Jul 28, 2017 at 12:16 PM, Viresh Kumar <viresh.ku...@linaro.org> wrote: > On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU > from policy-A can change frequency of CPUs belonging to policy-B. > > This is quite common in case of ARM platforms where we don't > configure any per-cpu register. > > Add a flag to identify such platforms and update > cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is > set. > > Also enable the flag for cpufreq-dt driver which is used only on ARM > platforms currently. > > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org> > --- > drivers/cpufreq/cpufreq-dt.c | 1 + > include/linux/cpufreq.h | 18 ++++++++++++++++-- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c > index fef3c2160691..d83ab94d041a 100644 > --- a/drivers/cpufreq/cpufreq-dt.c > +++ b/drivers/cpufreq/cpufreq-dt.c > @@ -274,6 +274,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) > transition_latency = CPUFREQ_ETERNAL; > > policy->cpuinfo.transition_latency = transition_latency; > + policy->dvfs_possible_from_any_cpu = true; > > return 0; > > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index b3b6e8203e82..227cd0f13300 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -127,6 +127,15 @@ struct cpufreq_policy { > */ > unsigned int transition_delay_us; > > + /* > + * Remote DVFS flag (Not added to the driver structure as we don't > want > + * to access another structure from scheduler hotpath). > + * > + * Should be set if CPUs can do DVFS on behalf of other CPUs from > + * different cpufreq policies. > + */ > + bool dvfs_possible_from_any_cpu; > + > /* Cached frequency lookup from cpufreq_driver_resolve_freq. */ > unsigned int cached_target_freq; > int cached_resolved_idx; > @@ -564,8 +573,13 @@ struct governor_attr { > > static inline bool cpufreq_can_do_remote_dvfs(struct cpufreq_policy *policy) > { > - /* Allow remote callbacks only on the CPUs sharing cpufreq policy */ > - if (cpumask_test_cpu(smp_processor_id(), policy->cpus)) > + /* > + * Allow remote callbacks if: > + * - dvfs_possible_from_any_cpu flag is set > + * - the local and remote CPUs share cpufreq policy > + */ > + if (policy->dvfs_possible_from_any_cpu || > + cpumask_test_cpu(smp_processor_id(), policy->cpus)) > return true; > > return false;
Currently sugov threads in the schedutil governor are pinned to the policy CPUs. schedutil can now make use of this new dvfs_possible_from_any_cpu flag and avoid the pinning, right? Thanks, Pavan -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project