Better explanation of jump-to-CFS optimization removal

GSN-EDF and friends rely on being called even if there is currently
no runnable real-time task on the runqueue for (at least) two reasons:
1) To initiate migrations. LITMUS^RT pull tasks for migrations; this requires
     plugins to be called even if no task is currently present.
2) To maintain invariants when jobs block.

1 files changed, 4 insertions, 0 deletions

diff --git a/litmus/sched_litmus.c b/litmus/sched_litmus.c
index 9906e059879a..64ad5db07795 100644
--- a/litmus/sched_litmus.c
+++ b/litmus/sched_litmus.c
@@ -156,6 +156,8 @@ static void enqueue_task_litmus(struct rq *rq, struct task_struct *p,
                 sched_trace_task_resume(p);
                 tsk_rt(p)->present = 1;
                 litmus->task_wake_up(p);
+
+                rq->litmus.nr_running++;
         } else
                 TRACE_TASK(p, "ignoring an enqueue, not a wake up.\n");
 }
@@ -166,6 +168,8 @@ static void dequeue_task_litmus(struct rq *rq, struct task_struct *p, int sleep)
                 litmus->task_block(p);
                 tsk_rt(p)->present = 0;
                 sched_trace_task_block(p);
+
+                rq->litmus.nr_running--;
         } else
                 TRACE_TASK(p, "ignoring a dequeue, not going to sleep.\n");
 }