sched/fair: calculate delta runnable load only when it's needed

Move the code of calculation for delta_sum/delta_avg to where
it is really needed to be done.

Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200103114400.17668-1-rocking@linux.alibaba.com

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d292883..32c5421 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3366,16 +3366,17 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
 
        runnable_load_sum = (s64)se_runnable(se) * runnable_sum;
        runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX);
-       delta_sum = runnable_load_sum - se_weight(se) * se->avg.runnable_load_sum;
-       delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
-
-       se->avg.runnable_load_sum = runnable_sum;
-       se->avg.runnable_load_avg = runnable_load_avg;
 
        if (se->on_rq) {
+               delta_sum = runnable_load_sum -
+                               se_weight(se) * se->avg.runnable_load_sum;
+               delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
                add_positive(&cfs_rq->avg.runnable_load_avg, delta_avg);
                add_positive(&cfs_rq->avg.runnable_load_sum, delta_sum);
        }
+
+       se->avg.runnable_load_sum = runnable_sum;
+       se->avg.runnable_load_avg = runnable_load_avg;
 }
 
 static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)