Trigger cpufreq updates any time the number of soft_affined task changes.

-ck

---
 kernel/sched/bfs.c       |   31 ++++++++++++++++++++++---------
 kernel/sched/bfs_sched.h |   12 ++++++++++++
 2 files changed, 34 insertions(+), 9 deletions(-)

Index: linux-4.7-ck4/kernel/sched/bfs.c
===================================================================
--- linux-4.7-ck4.orig/kernel/sched/bfs.c	2016-09-13 17:21:52.354247208 +1000
+++ linux-4.7-ck4/kernel/sched/bfs.c	2016-09-13 17:21:52.352247253 +1000
@@ -1025,7 +1025,6 @@ static void update_load_avg(struct rq *r
 			load = 0;
 		load += rq->soft_affined * rq_load_avg(rq) * us_interval * 80 / 32768 / 128;
 		rq->load_avg = load;
-		cpufreq_trigger(grq.niffies, rq->load_avg);
 	}
 	rq->load_update = rq->clock;
 }
@@ -1057,6 +1056,7 @@ static void activate_task(struct task_st
 	grq.nr_running++;
 	inc_qnr();
 	update_load_avg(rq);
+	cpufreq_trigger(grq.niffies, rq->load_avg);
 }
 
 static inline void clear_sticky(struct task_struct *p);
@@ -1074,18 +1074,21 @@ static inline void deactivate_task(struc
 	grq.nr_running--;
 	clear_sticky(p);
 	update_load_avg(rq);
+	cpufreq_trigger(grq.niffies, rq->load_avg);
 }
 
 #ifdef CONFIG_SMP
 void set_task_cpu(struct task_struct *p, unsigned int cpu)
 {
+	unsigned int tcpu;
+
 #ifdef CONFIG_LOCKDEP
 	/*
 	 * The caller should hold grq lock.
 	 */
 	WARN_ON_ONCE(debug_locks && !lockdep_is_held(&grq.lock));
 #endif
-	if (task_cpu(p) == cpu)
+	if ((tcpu = task_cpu(p)) == cpu)
 		return;
 	trace_sched_migrate_task(p, cpu);
 	perf_event_task_migrate(p);
@@ -1097,8 +1100,21 @@ void set_task_cpu(struct task_struct *p,
 	 */
 	smp_wmb();
 	if (p->on_rq) {
-		task_rq(p)->soft_affined--;
-		cpu_rq(cpu)->soft_affined++;
+		struct rq *rq;
+
+		/*
+		 * set_task_cpu can be set on other CPUs so call cpufreq_trigger
+		 * explicitly telling it what CPU is being updated as the value
+		 * of soft_affined has changed.
+		 */
+		rq = task_rq(p);
+		rq->soft_affined--;
+		update_load_avg(rq);
+		other_cpufreq_trigger(tcpu, grq.niffies, rq->load_avg);
+		rq = cpu_rq(cpu);
+		rq->soft_affined++;
+		update_load_avg(rq);
+		other_cpufreq_trigger(cpu, grq.niffies, rq->load_avg);
 	}
 	task_thread_info(p)->cpu = cpu;
 }
@@ -3153,11 +3169,8 @@ void scheduler_tick(void)
 	if (!rq_idle(rq))
 		task_running_tick(rq);
 	else {
-		/*
-		 * Trigger cpufreq update while we're idle. Soft affined will
-		 * be zero unless we have uninterruptible tasks.
-		 */
-		cpufreq_trigger(grq.niffies, rq->soft_affined);
+		update_load_avg(rq);
+		cpufreq_trigger(grq.niffies, rq->load_avg);
 		no_iso_tick();
 	}
 	rq->last_tick = rq->clock;
Index: linux-4.7-ck4/kernel/sched/bfs_sched.h
===================================================================
--- linux-4.7-ck4.orig/kernel/sched/bfs_sched.h	2016-09-13 17:21:52.354247208 +1000
+++ linux-4.7-ck4/kernel/sched/bfs_sched.h	2016-09-13 17:21:52.352247253 +1000
@@ -210,10 +210,22 @@ static inline void cpufreq_trigger(u64 t
                data->func(data, time, util, SCHED_CAPACITY_SCALE);
 }
 
+static inline void other_cpufreq_trigger(int cpu, u64 time, unsigned long util)
+{
+       struct update_util_data *data;
+
+       data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data, cpu));
+       if (data)
+               data->func(data, time, util, SCHED_CAPACITY_SCALE);
+}
 #else
 static inline void cpufreq_trigger(u64 time, unsigned long util)
 {
 }
+
+static inline void other_cpufreq_trigger(int cpu, u64 time, unsigned long util)
+{
+}
 #endif /* CONFIG_CPU_FREQ */
 
 #ifdef arch_scale_freq_capacity