Support waking up blocked tasks

edfsc_task_wake_up() is called when a task becomes unblocked. Since
we remove blocked tasks from the system in edfsc_gschedule(), this
must be implemented or the previously blocked task will be lost
forever.

1 files changed, 13 insertions, 1 deletions

diff --git a/litmus/sched_edfsc.c b/litmus/sched_edfsc.c
index 8a1cd8f1c85f..212aa8ed0394 100644
--- a/litmus/sched_edfsc.c
+++ b/litmus/sched_edfsc.c
@@ -1071,9 +1071,21 @@ static void edfsc_task_new(struct task_struct* t, int on_rq, int is_scheduled)
         TRACE("EDF-sc: task new %d\n", t->pid);
 }
 
+/**
+ * This is called by LITMUS when our task is being woken up after having
+ * previously blocked on something like console or disk I/O. This is a pair to
+ * the `if (blocks) unlink(entry->scheduled);` in edfsc_gschedule().
+ */
 static void edfsc_task_wake_up(struct task_struct *task)
 {
-        // TODO
+        unsigned long flags;
+
+        TRACE_TASK(task, "wake_up at %llu\n", litmus_clock());
+        raw_spin_lock_irqsave(&g_lock, flags);
+        // TODO: Look into handling sporadic tasks as sched_gsnedf.c does
+        requeue(task);
+        // TODO: Look into queuing preemption as sched_gsnedf.c does?
+        raw_spin_unlock_irqrestore(&g_lock, flags);
 }
 
 static void edfsc_task_block(struct task_struct *t)