sched/fair: Fix the wrong throttled clock time for cfs_rq_clock_task()

Two minor fixes for cfs_rq_clock_task():

 1) If cfs_rq is currently being throttled, we need to subtract the cfs
    throttled clock time.

 2) Make "throttled_clock_task_time" update SMP unrelated. Now UP cases
    need it as well.

Signed-off-by: Xunlei Pang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: Xunlei Pang

kernel/sched/fair.c

@@ -3688,7 +3688,7 @@ static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
 static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq)
 {
 	if (unlikely(cfs_rq->throttle_count))
-		return cfs_rq->throttled_clock_task;
+		return cfs_rq->throttled_clock_task - cfs_rq->throttled_clock_task_time;
 
 	return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time;
 }
@@ -3826,13 +3826,11 @@ static int tg_unthrottle_up(struct task_group *tg, void *data)
 	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
 
 	cfs_rq->throttle_count--;
-#ifdef CONFIG_SMP
 	if (!cfs_rq->throttle_count) {
 		/* adjust cfs_rq_clock_task() */
 		cfs_rq->throttled_clock_task_time += rq_clock_task(rq) -
 					     cfs_rq->throttled_clock_task;
 	}
-#endif
 
 	return 0;
 }