sched/cpufreq: Factor out utilization to frequency mapping

The schedutil governor maps utilization values to frequencies by applying
a 25% margin. Since this sort of mapping mechanism can be needed by other
users (i.e. EAS), factor the utilization-to-frequency mapping code out
of schedutil and move it to include/linux/sched/cpufreq.h to avoid code
duplication. The new map_util_freq() function is inlined to avoid
overheads.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>

diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h
index 59667444669fc0f10de065cefe770f11fff1c1b6..afa940cd50dc5355bed0815c0d7a0c20a548fb98 100644 (file)
--- a/include/linux/sched/cpufreq.h
+++ b/include/linux/sched/cpufreq.h
@@ -20,6 +20,12 @@ void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
                        void (*func)(struct update_util_data *data, u64 time,
                                    unsigned int flags));
 void cpufreq_remove_update_util_hook(int cpu);
+
+static inline unsigned long map_util_freq(unsigned long util,
+                                       unsigned long freq, unsigned long cap)
+{
+       return (freq + (freq >> 2)) * util / cap;
+}
 #endif /* CONFIG_CPU_FREQ */
 
 #endif /* _LINUX_SCHED_CPUFREQ_H */

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 3fffad3bc8a86a366b93d5480c8840f34a84121e..f5206c950143e7817da4e90f60a0e4c60ba928c9 100644 (file)
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -13,6 +13,7 @@
 
 #include "sched.h"
 
+#include <linux/sched/cpufreq.h>
 #include <trace/events/power.h>
 
 struct sugov_tunables {
@@ -167,7 +168,7 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
        unsigned int freq = arch_scale_freq_invariant() ?
                                policy->cpuinfo.max_freq : policy->cur;
 
-       freq = (freq + (freq >> 2)) * util / max;
+       freq = map_util_freq(util, freq, max);
 
        if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
                return sg_policy->next_freq;