[RFC][PATCH 1/5] sched/fair: Update the rq clock before detaching tasks

[Matt Fleming]

detach_task_cfs_rq() may indirectly call rq_clock() to inform the
cpufreq code that the rq utilisation has changed. In which case, we
need to update the rq clock.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: Yuyang Du <yuyang.du@xxxxxxxxx>
Cc: Byungchul Park <byungchul.park@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 218f8e83db73..02856647339d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8378,6 +8378,8 @@ static void detach_task_cfs_rq(struct task_struct *p)
 	struct sched_entity *se = &p->se;
 	struct cfs_rq *cfs_rq = cfs_rq_of(se);
 
+	update_rq_clock(task_rq(p));
+
 	if (!vruntime_normalized(p)) {
 		/*
 		 * Fix up our vruntime so that the current sleep doesn't
-- 
2.7.3