sched: Move notify_migration() under CONFIG_SCHED_HMP

notify_migration() is a HMP specific function that relies on all
of its contents to be stubbed out for !CONFIG_SCHED_HMP. However,
it still maintains calls to rcu_read_lock/unlock(). In the !HMP
case these calls are simply redundant. Move the function under
CONFIG_SCHED_HMP and add a stub when the config is not defined so
that there is no overhead.

Change-Id: Iad914f31b629e81e403b0e89796b2b0f1d081695
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>

3 files changed, 25 insertions, 19 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6836851d416f..a790d101d120 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1134,25 +1134,6 @@ static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_
 	return rq;
 }
 
-static void notify_migration(int src_cpu, int dest_cpu, bool src_cpu_dead,
-			     struct task_struct *p)
-{
-	bool check_groups;
-
-	rcu_read_lock();
-	check_groups = task_in_related_thread_group(p);
-	rcu_read_unlock();
-
-	if (!same_freq_domain(src_cpu, dest_cpu)) {
-		if (!src_cpu_dead)
-			check_for_freq_change(cpu_rq(src_cpu), false,
-					      check_groups);
-		check_for_freq_change(cpu_rq(dest_cpu), false, check_groups);
-	} else {
-		check_for_freq_change(cpu_rq(dest_cpu), true, check_groups);
-	}
-}
-
 /*
  * migration_cpu_stop - this will be executed by a highprio stopper thread
  * and performs thread migration by bumping thread off CPU then
diff --git a/kernel/sched/hmp.c b/kernel/sched/hmp.c
index 84cce75c6e50..162d4a0c950c 100644
--- a/kernel/sched/hmp.c
+++ b/kernel/sched/hmp.c
@@ -1786,6 +1786,25 @@ void check_for_freq_change(struct rq *rq, bool check_pred, bool check_groups)
 		(void *)(long)cpu);
 }
 
+void notify_migration(int src_cpu, int dest_cpu, bool src_cpu_dead,
+			     struct task_struct *p)
+{
+	bool check_groups;
+
+	rcu_read_lock();
+	check_groups = task_in_related_thread_group(p);
+	rcu_read_unlock();
+
+	if (!same_freq_domain(src_cpu, dest_cpu)) {
+		if (!src_cpu_dead)
+			check_for_freq_change(cpu_rq(src_cpu), false,
+					      check_groups);
+		check_for_freq_change(cpu_rq(dest_cpu), false, check_groups);
+	} else {
+		check_for_freq_change(cpu_rq(dest_cpu), true, check_groups);
+	}
+}
+
 static int account_busy_for_cpu_time(struct rq *rq, struct task_struct *p,
 				     u64 irqtime, int event)
 {
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 0bae93891647..b09d3a1a026f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1300,6 +1300,9 @@ struct related_thread_group *task_related_thread_group(struct task_struct *p)
 extern void
 check_for_freq_change(struct rq *rq, bool check_pred, bool check_groups);
 
+extern void notify_migration(int src_cpu, int dest_cpu,
+			bool src_cpu_dead, struct task_struct *p);
+
 struct group_cpu_time {
 	u64 curr_runnable_sum;
 	u64 prev_runnable_sum;
@@ -1580,6 +1583,9 @@ static inline int update_preferred_cluster(struct related_thread_group *grp,
 static inline void
 check_for_freq_change(struct rq *rq, bool check_pred, bool check_groups) { }
 
+static inline void notify_migration(int src_cpu, int dest_cpu,
+			bool src_cpu_dead, struct task_struct *p) { }
+
 static inline int same_freq_domain(int src_cpu, int dst_cpu)
 {
 	return 1;