On Fri, Jul 7, 2017 at 6:01 PM, Dietmar Eggemann <[email protected]> wrote: > On 06/07/17 11:40, Viresh Kumar wrote: >> On 06-07-17, 10:49, Dietmar Eggemann wrote: > > [...] > >>> In case arch_set_freq_scale() is not defined (and because of the >>> pr_debug() drivers/cpufreq/cpufreq.c is not compiled with -DDEBUG) >> >> The line within () needs to be improved to convey a clear message. > > Probably not needed anymore. See below. > > [...] > >>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >>> index 9bf97a366029..a04c5886a5ce 100644 >>> --- a/drivers/cpufreq/cpufreq.c >>> +++ b/drivers/cpufreq/cpufreq.c >>> @@ -347,6 +347,28 @@ static void __cpufreq_notify_transition(struct >>> cpufreq_policy *policy, >>> } >>> } >>> >>> +/********************************************************************* >>> + * FREQUENCY INVARIANT CPU CAPACITY SUPPORT * >>> + *********************************************************************/ >>> + >>> +#ifndef arch_set_freq_scale >>> +static void arch_set_freq_scale(struct cpumask *cpus, unsigned long >>> cur_freq, >>> + unsigned long max_freq) >>> +{} >>> +#endif >>> + >>> +static void cpufreq_set_freq_scale(struct cpufreq_policy *policy, >>> + struct cpufreq_freqs *freqs) >>> +{ >>> + unsigned long cur_freq = freqs ? freqs->new : policy->cur; >>> + unsigned long max_freq = policy->cpuinfo.max_freq; >>> + >>> + pr_debug("cpus %*pbl cur/cur max freq %lu/%lu kHz\n", >>> + cpumask_pr_args(policy->related_cpus), cur_freq, max_freq); >>> + >>> + arch_set_freq_scale(policy->related_cpus, cur_freq, max_freq); >> >> I am not sure why all these are required to be sent here and will come back >> to >> it later on after going through other patches. > > See below. > >>> +} >>> + >>> /** >>> * cpufreq_notify_transition - call notifier chain and adjust_jiffies >>> * on frequency transition. >>> @@ -405,6 +427,8 @@ void cpufreq_freq_transition_begin(struct >>> cpufreq_policy *policy, >>> >>> spin_unlock(&policy->transition_lock); >>> >>> + cpufreq_set_freq_scale(policy, freqs); >>> + >> >> Why do this before even changing the frequency ? We may fail while changing >> it. >> >> IMHO, you should call this routine whenever we update policy->cur and that >> happens regularly in __cpufreq_notify_transition() and few other places.. > > See below. > >>> cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); >>> } >>> EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); >>> @@ -2203,6 +2227,8 @@ static int cpufreq_set_policy(struct cpufreq_policy >>> *policy, >>> blocking_notifier_call_chain(&cpufreq_policy_notifier_list, >>> CPUFREQ_NOTIFY, new_policy); >>> >>> + cpufreq_set_freq_scale(new_policy, NULL); >> >> Why added it here ? To get it initialized ? If yes, then we should do that in >> cpufreq_online() where we first initialize policy->cur. > > I agree. This can go away. Initialization is not really needed here. We > initialize > the scale values to SCHED_CAPACITY_SCALE at boot-time. > >> Apart from this, you also need to update this in the schedutil governor (if >> you >> haven't done that in this series later) as that also updates policy->cur in >> the >> fast path. > > So what about I call arch_set_freq_scale() in __cpufreq_notify_transition() > in the > CPUFREQ_POSTCHANGE case for slow-switching and in > cpufreq_driver_fast_switch() for > fast-switching?
Why don't you do this in drivers instead of in the core? Ultimately, the driver knows what frequency it has requested, so why can't it call arch_set_freq_scale()? Thanks, Rafael
