sched: ems: update cpu_scale when policy is updated

When policy->max is pressed, the performance of the cpu is
constrained. In the constrained state, the cpu capacity also
changes, and the overutil condition changes accordingly, so
the cpu scale is updated whenever policy is changed.

Change-Id: Ie6938e605d55cf700164a7512ffd6c41a747cbbc
Signed-off-by: Park Bumgyu <bumgyu.park@samsung.com>

diff --git a/kernel/sched/ems/energy.c b/kernel/sched/ems/energy.c
index b3490474d167856dca7e4e5c0548d1b66dadb1a5..663dbe26c45e5fbc9d0af429f8bc981e70a430ee 100644 (file)
--- a/kernel/sched/ems/energy.c
+++ b/kernel/sched/ems/energy.c
@@ -5,6 +5,7 @@
  * Park Bumgyu <bumgyu.park@samsung.com>
  */
 
+#include <linux/cpufreq.h>
 #include <trace/events/ems.h>
 
 #include "ems.h"
@@ -387,6 +388,43 @@ static void show_energy_table(struct energy_table *table, int cpu)
        }
 }
 
+/*
+ * Store the original capacity to update the cpu capacity according to the
+ * max frequency of cpufreq.
+ */
+DEFINE_PER_CPU(unsigned long, cpu_orig_scale) = SCHED_CAPACITY_SCALE;
+
+static int sched_cpufreq_policy_callback(struct notifier_block *nb,
+                                       unsigned long event, void *data)
+{
+       struct cpufreq_policy *policy = data;
+       unsigned long cpu_scale, max_scale;
+       int cpu;
+
+       if (event != CPUFREQ_NOTIFY)
+               return NOTIFY_DONE;
+
+       /*
+        * When policy->max is pressed, the performance of the cpu is constrained.
+        * In the constrained state, the cpu capacity also changes, and the
+        * overutil condition changes accordingly, so the cpu scale is updated
+        * whenever policy is changed.
+        */
+       max_scale = (policy->max << SCHED_CAPACITY_SHIFT);
+       max_scale /= policy->cpuinfo.max_freq;
+       for_each_cpu(cpu, policy->related_cpus) {
+               cpu_scale = per_cpu(cpu_orig_scale, cpu) * max_scale;
+               cpu_scale = cpu_scale >> SCHED_CAPACITY_SHIFT;
+               topology_set_cpu_scale(cpu, cpu_scale);
+       }
+
+       return NOTIFY_OK;
+}
+
+static struct notifier_block sched_cpufreq_policy_notifier = {
+       .notifier_call = sched_cpufreq_policy_callback,
+};
+
 /*
  * Whenever frequency domain is registered, and energy table corresponding to
  * the domain is created. Because cpu in the same frequency domain has the same
@@ -476,6 +514,7 @@ void init_sched_energy_table(struct cpumask *cpus, int table_size,
                show_energy_table(table, cpu);
 
                last_state = table->nr_states - 1;
+               per_cpu(cpu_orig_scale, cpu) = table->states[last_state].cap;
                topology_set_cpu_scale(cpu, table->states[last_state].cap);
 
                rcu_read_lock();
@@ -522,7 +561,9 @@ static int __init init_sched_energy_data(void)
                pr_info("cpu%d mips=%d, coefficient=%d\n", cpu, table->mips, table->coefficient);
        }
 
+       cpufreq_register_notifier(&sched_cpufreq_policy_notifier, CPUFREQ_POLICY_NOTIFIER);
+
        return 0;
 }
-pure_initcall(init_sched_energy_data);
+core_initcall(init_sched_energy_data);
 #endif /* CONFIG_SIMPLIFIED_ENERGY_MODEL */