sched: track cfs_rq->curr on !group-scheduling too

Noticed by Roman Zippel: use cfs_rq->curr in the !group-scheduling
case too. Small micro-optimization and cleanup effect:

   text    data     bss     dec     hex filename
   36269    3482      24   39775    9b5f sched.o.before
   36177    3486      24   39687    9b07 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

kernel/sched.c

@@ -189,11 +189,11 @@ struct cfs_rq {
 	struct rb_root tasks_timeline;
 	struct rb_node *rb_leftmost;
 	struct rb_node *rb_load_balance_curr;
-#ifdef CONFIG_FAIR_GROUP_SCHED
 	/* 'curr' points to currently running entity on this cfs_rq.
 	 * It is set to NULL otherwise (i.e when none are currently running).
 	 */
 	struct sched_entity *curr;
+#ifdef CONFIG_FAIR_GROUP_SCHED
 	struct rq *rq;	/* cpu runqueue to which this cfs_rq is attached */
 
 	/* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in

kernel/sched_fair.c

@@ -111,51 +111,38 @@ extern struct sched_class fair_sched_class;
  * CFS operations on generic schedulable entities:
  */
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-
-/* cpu runqueue to which this cfs_rq is attached */
-static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
-{
-	return cfs_rq->rq;
-}
-
 /* currently running entity (if any) on this cfs_rq */
 static inline struct sched_entity *cfs_rq_curr(struct cfs_rq *cfs_rq)
 {
 	return cfs_rq->curr;
 }
 
-/* An entity is a task if it doesn't "own" a runqueue */
-#define entity_is_task(se)	(!se->my_q)
-
 static inline void
 set_cfs_rq_curr(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	cfs_rq->curr = se;
 }
 
-#else	/* CONFIG_FAIR_GROUP_SCHED */
+#ifdef CONFIG_FAIR_GROUP_SCHED
 
+/* cpu runqueue to which this cfs_rq is attached */
 static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
 {
-	return container_of(cfs_rq, struct rq, cfs);
+	return cfs_rq->rq;
 }
 
-static inline struct sched_entity *cfs_rq_curr(struct cfs_rq *cfs_rq)
-{
-	struct rq *rq = rq_of(cfs_rq);
+/* An entity is a task if it doesn't "own" a runqueue */
+#define entity_is_task(se)	(!se->my_q)
 
-	if (unlikely(rq->curr->sched_class != &fair_sched_class))
-		return NULL;
+#else	/* CONFIG_FAIR_GROUP_SCHED */
 
-	return &rq->curr->se;
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+	return container_of(cfs_rq, struct rq, cfs);
 }
 
 #define entity_is_task(se)	1
 
-static inline void
-set_cfs_rq_curr(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
-
 #endif	/* CONFIG_FAIR_GROUP_SCHED */
 
 static inline struct task_struct *task_of(struct sched_entity *se)