[tip:sched/core] sched/fair: Fix the wrong throttled clock time for cfs_rq_clock_task()

[tip-bot for Xunlei Pang]

Commit-ID:  1a99ae3f00d3c7c7885ee529ac9a874b19caa0cf
Gitweb:     http://git.kernel.org/tip/1a99ae3f00d3c7c7885ee529ac9a874b19caa0cf
Author:     Xunlei Pang <xlpang@xxxxxxxxxx>
AuthorDate: Tue, 10 May 2016 21:03:18 +0800
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 3 Jun 2016 09:18:56 +0200

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 <xlpang@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1462885398-14724-1-git-send-email-xlpang@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/sched/fair.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 218f8e8..1e87bb6 100644
--- a/kernel/sched/fair.c
+++ b/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;
 }