sched/fair: Fix runnable_avg for throttled cfs

When a cfs_rq is throttled, its group entity is dequeued and its running
tasks are removed. We must update runnable_avg with the old h_nr_running
and update group_se->runnable_weight with the new h_nr_running at each
level of the hierarchy.

Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fixes: 9f68395333ad ("sched/pelt: Add a new runnable average signal")
Link: https://lkml.kernel.org/r/20200227154115.8332-1-vincent.guittot@linaro.org

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3887b7323abdf424c2903f905357c8fac2a10f33..54bd6280676e337a2aa4c9ad5b3e3cf517c66d90 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4720,8 +4720,13 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
                if (!se->on_rq)
                        break;
 
-               if (dequeue)
+               if (dequeue) {
                        dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
+               } else {
+                       update_load_avg(qcfs_rq, se, 0);
+                       se_update_runnable(se);
+               }
+
                qcfs_rq->h_nr_running -= task_delta;
                qcfs_rq->idle_h_nr_running -= idle_task_delta;
 
@@ -4789,8 +4794,13 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
                        enqueue = 0;
 
                cfs_rq = cfs_rq_of(se);
-               if (enqueue)
+               if (enqueue) {
                        enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
+               } else {
+                       update_load_avg(cfs_rq, se, 0);
+                       se_update_runnable(se);
+               }
+
                cfs_rq->h_nr_running += task_delta;
                cfs_rq->idle_h_nr_running += idle_task_delta;