/* Prepare a task for running in RT mode
*/
static void psnedf_task_new(struct task_struct * t, int on_rq, int is_scheduled)
{
rt_domain_t* edf = task_edf(t);
psnedf_domain_t* pedf = task_pedf(t);
unsigned long flags;
TRACE_TASK(t, "psn edf: task new, cpu = %d\n",
t->rt_param.task_params.cpu);
/* setup job parameters */
release_at(t, litmus_clock());
/* The task should be running in the queue, otherwise signal
* code will try to wake it up with fatal consequences.
*/
raw_readyq_lock_irqsave(&pedf->slock, flags);
if (is_scheduled) {
/* there shouldn't be anything else scheduled at the time */
BUG_ON(pedf->scheduled);
pedf->scheduled = t;
} else {
/* !is_scheduled means it is not scheduled right now, but it
* does not mean that it is suspended. If it is not suspended,
* it still needs to be requeued. If it is suspended, there is
* nothing that we need to do as it will be handled by the
* wake_up() handler. */
if (is_running(t)) {
requeue(t, edf);
/* maybe we have to reschedule */
psnedf_preempt_check(pedf);
}
}
raw_readyq_unlock_irqrestore(&pedf->slock, flags);
}
/* 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 void pfair_release_at(struct task_struct* task, lt_t start)
{
unsigned long flags;
quanta_t release;
BUG_ON(!is_realtime(task));
raw_spin_lock_irqsave(&pfair_lock, flags);
release_at(task, start);
release = time2quanta(start, CEIL);
if (release - pfair_time >= PFAIR_MAX_PERIOD)
release = pfair_time + PFAIR_MAX_PERIOD;
TRACE_TASK(task, "sys release at %lu\n", release);
drop_all_references(task);
prepare_release(task, release);
pfair_add_release(task);
/* Clear sporadic release flag, since this release subsumes any
* sporadic release on wake.
*/
tsk_pfair(task)->sporadic_release = 0;
raw_spin_unlock_irqrestore(&pfair_lock, flags);
}
static void pfair_task_wake_up(struct task_struct *t)
{
unsigned long flags;
lt_t now;
TRACE_TASK(t, "wakes at %llu, release=%lu, pfair_time:%lu\n",
litmus_clock(), cur_release(t), pfair_time);
raw_spin_lock_irqsave(&pfair_lock, flags);
/* It is a little unclear how to deal with Pfair
* tasks that block for a while and then wake. For now,
* if a task blocks and wakes before its next job release,
* then it may resume if it is currently linked somewhere
* (as if it never blocked at all). Otherwise, we have a
* new sporadic job release.
*/
if (tsk_pfair(t)->sporadic_release) {
now = litmus_clock();
release_at(t, now);
prepare_release(t, time2quanta(now, CEIL));
sched_trace_task_release(t);
/* FIXME: race with pfair_time advancing */
pfair_add_release(t);
tsk_pfair(t)->sporadic_release = 0;
}
check_preempt(t);
raw_spin_unlock_irqrestore(&pfair_lock, flags);
TRACE_TASK(t, "wake up done at %llu\n", litmus_clock());
}
static void psnedf_task_wake_up(struct task_struct *task)
{
unsigned long flags;
psnedf_domain_t* pedf = task_pedf(task);
rt_domain_t* edf = task_edf(task);
lt_t now;
TRACE_TASK(task, "wake_up at %llu\n", litmus_clock());
raw_readyq_lock_irqsave(&pedf->slock, flags);
set_task_state(task, TASK_RUNNING);
BUG_ON(is_queued(task));
now = litmus_clock();
if (is_sporadic(task) && is_tardy(task, now)
#ifdef CONFIG_LITMUS_LOCKING
/* We need to take suspensions because of semaphores into
* account! If a job resumes after being suspended due to acquiring
* a semaphore, it should never be treated as a new job release.
*/
&& !is_priority_boosted(task)
#endif
) {
/* new sporadic release */
release_at(task, now);
sched_trace_task_release(task);
}
budget_state_machine(task,on_wakeup);
/* Only add to ready queue if it is not the currently-scheduled
* task. This could be the case if a task was woken up concurrently
* on a remote CPU before the executing CPU got around to actually
* de-scheduling the task, i.e., wake_up() raced with schedule()
* and won.
*/
if (pedf->scheduled != task) {
requeue(task, edf);
psnedf_preempt_check(pedf);
}
raw_readyq_unlock_irqrestore(&pedf->slock, flags);
TRACE_TASK(task, "wake up done\n");
}
