A frequency-invariant load-tracking solution based on cpufreq transition notifier will not work for future fast frequency switching policies. That is why a different solution is presented with this patch.
Let cpufreq call the function arch_set_freq_scale() to pass the current frequency, the max supported frequency and the cpumask of the related cpus to a consumer (an arch) which defines arch_set_freq_scale(). The consumer has to associate arch_set_freq_scale with the name of its own implementation foo_set_freq_scale() to overwrite the empty standard definition in drivers/cpufreq/cpufreq.c. An arch could do this in one of its arch-specific header files (e.g. arch/$ARCH/include/asm/topology.h) which gets included in drivers/cpufreq/cpufreq.c. 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 function cpufreq_set_freq_scale() gets compiled out. Cc: Rafael J. Wysocki <[email protected]> Cc: Viresh Kumar <[email protected]> Signed-off-by: Dietmar Eggemann <[email protected]> --- drivers/cpufreq/cpufreq.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) 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); +} + /** * 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); + 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); + policy->min = new_policy->min; policy->max = new_policy->max; -- 2.11.0
