[PATCH] sched: remove root_task_group

[Yong Zhang <yong.zhang0@gmail.com>]

root_task_group is the leftover of USER_SCHED, now it's always
same to init_task_group.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 kernel/sched.c           |    4 +---
 kernel/sched_autogroup.c |    2 +-
 kernel/sched_fair.c      |    2 +-
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 114a0de..2ba7a7e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -278,8 +278,6 @@ struct task_group {
 #endif
 };
 
-#define root_task_group init_task_group
-
 /* task_group_lock serializes the addition/removal of task groups */
 static DEFINE_SPINLOCK(task_group_lock);
 
@@ -1447,7 +1445,7 @@ static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
 	int ret;
 
 	rcu_read_lock();
-	parent = &root_task_group;
+	parent = &init_task_group;
 down:
 	ret = (*down)(parent, data);
 	if (ret)
diff --git a/kernel/sched_autogroup.c b/kernel/sched_autogroup.c
index c80fedc..ff6c88c 100644
--- a/kernel/sched_autogroup.c
+++ b/kernel/sched_autogroup.c
@@ -90,7 +90,7 @@ out_fail:
 static inline bool
 task_wants_autogroup(struct task_struct *p, struct task_group *tg)
 {
-	if (tg != &root_task_group)
+	if (tg != &init_task_group)
 		return false;
 
 	if (p->sched_class != &fair_sched_class)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c62ebae..a994a28 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1348,7 +1348,7 @@ static void task_waking_fair(struct rq *rq, struct task_struct *p)
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 /*
- * effective_load() calculates the load change as seen from the root_task_group
+ * effective_load() calculates the load change as seen from the init_task_group
  *
  * Adding load to a group doesn't make a group heavier, but can cause movement
  * of group shares between cpus. Assuming the shares were perfectly aligned one
-- 
1.7.0.4