static void psnedf_tick(struct task_struct *t)
{
psnedf_domain_t *pedf = local_pedf;
/* Check for inconsistency. We don't need the lock for this since
* ->scheduled is only changed in schedule, which obviously is not
* executing in parallel on this CPU
*/
BUG_ON(is_realtime(t) && t != pedf->scheduled);
if (is_realtime(t) &&
tsk_rt(t)->budget.ops && budget_quantum_tracked(t) &&
budget_exhausted(t)) {
TRACE_TASK(t, "budget exhausted\n");
budget_state_machine2(t,on_exhausted,!IN_SCHEDULE);
}
}
static struct task_struct* demo_schedule(struct task_struct * prev)
{
struct demo_cpu_state *local_state = local_cpu_state();
/* next == NULL means "schedule background work". */
struct task_struct *next = NULL;
/* prev's task state */
int exists, out_of_time, job_completed, self_suspends, preempt, resched;
raw_spin_lock(&local_state->local_queues.ready_lock);
BUG_ON(local_state->scheduled && local_state->scheduled != prev);
BUG_ON(local_state->scheduled && !is_realtime(prev));
exists = local_state->scheduled != NULL;
self_suspends = exists && !is_current_running();
out_of_time = exists && budget_enforced(prev) && budget_exhausted(prev);
job_completed = exists && is_completed(prev);
/* preempt is true if task `prev` has lower priority than something on
* the ready queue. */
preempt = edf_preemption_needed(&local_state->local_queues, prev);
/* check all conditions that make us reschedule */
resched = preempt;
/* if `prev` suspends, it CANNOT be scheduled anymore => reschedule */
if (self_suspends) {
resched = 1;
}
/* also check for (in-)voluntary job completions */
if (out_of_time || job_completed) {
demo_job_completion(prev, out_of_time);
resched = 1;
}
if (resched) {
/* First check if the previous task goes back onto the ready
* queue, which it does if it did not self_suspend.
*/
if (exists && !self_suspends) {
demo_requeue(prev, local_state);
}
next = __take_ready(&local_state->local_queues);
} else {
/* No preemption is required. */
next = local_state->scheduled;
}
local_state->scheduled = next;
if (exists && prev != next) {
TRACE_TASK(prev, "descheduled.\n");
}
if (next) {
TRACE_TASK(next, "scheduled.\n");
}
/* This mandatory. It triggers a transition in the LITMUS^RT remote
* preemption state machine. Call this AFTER the plugin has made a local
* scheduling decision.
*/
sched_state_task_picked();
raw_spin_unlock(&local_state->local_queues.ready_lock);
return next;
}
