/* Called when the state of tsk changes back to TASK_RUNNING.
* We need to requeue the task.
*
* NOTE: If a sporadic task is suspended for a long time,
* this might actually be an event-driven release of a new job.
*/
static void demo_task_resume(struct task_struct *tsk)
{
unsigned long flags;
struct demo_cpu_state *state = cpu_state_for(get_partition(tsk));
lt_t now;
TRACE_TASK(tsk, "wake_up at %llu\n", litmus_clock());
raw_spin_lock_irqsave(&state->local_queues.ready_lock, flags);
now = litmus_clock();
if (is_sporadic(tsk) && is_tardy(tsk, now)) {
/* This sporadic task was gone for a "long" time and woke up past
* its deadline. Give it a new budget by triggering a job
* release. */
release_at(tsk, now);
}
/* This check is required to avoid races with tasks that resume before
* the scheduler "noticed" that it resumed. That is, the wake up may
* race with the call to schedule(). */
if (state->scheduled != tsk) {
demo_requeue(tsk, state);
if (edf_preemption_needed(&state->local_queues, state->scheduled)) {
preempt_if_preemptable(state->scheduled, state->cpu);
}
}
raw_spin_unlock_irqrestore(&state->local_queues.ready_lock, flags);
}
static void demo_task_new(struct task_struct *tsk, int on_runqueue,
int is_running)
{
/* We'll use this to store IRQ flags. */
unsigned long flags;
struct demo_cpu_state *state = cpu_state_for(get_partition(tsk));
lt_t now;
TRACE_TASK(tsk, "is a new RT task %llu (on runqueue:%d, running:%d)\n",
litmus_clock(), on_runqueue, is_running);
/* Acquire the lock protecting the state and disable interrupts. */
raw_spin_lock_irqsave(&state->local_queues.ready_lock, flags);
now = litmus_clock();
/* Release the first job now. */
release_at(tsk, now);
if (is_running) {
/* If tsk is running, then no other task can be running
* on the local CPU. */
BUG_ON(state->scheduled != NULL);
state->scheduled = tsk;
} else if (on_runqueue) {
demo_requeue(tsk, state);
}
if (edf_preemption_needed(&state->local_queues, state->scheduled))
preempt_if_preemptable(state->scheduled, state->cpu);
raw_spin_unlock_irqrestore(&state->local_queues.ready_lock, flags);
}
static int demo_check_for_preemption_on_release(rt_domain_t *local_queues)
{
struct demo_cpu_state *state = container_of(local_queues, struct demo_cpu_state,
local_queues);
/* Because this is a callback from rt_domain_t we already hold
* the necessary lock for the ready queue. */
if (edf_preemption_needed(local_queues, state->scheduled)) {
preempt_if_preemptable(state->scheduled, state->cpu);
return 1;
}
return 0;
}
/* we assume the lock is being held */
static void preempt(psnedf_domain_t *pedf)
{
preempt_if_preemptable(pedf->scheduled, pedf->cpu);
}