inline static void arm_enforcement_timer(struct task_struct* t, int force)
{
struct enforcement_timer* et;
lt_t when_to_fire, remaining_budget;
lt_t now;
unsigned long flags;
BUG_ON(!t);
BUG_ON(!is_realtime(t));
et = &tsk_rt(t)->budget.timer;
if (et->armed) {
TRACE_TASK(t, "timer already armed!\n");
return;
}
if (!force) {
if ( (!budget_enforced(t) ||
(budget_enforced(t) &&
bt_flag_is_set(t, BTF_BUDGET_EXHAUSTED)))
&&
(!budget_signalled(t) ||
(budget_signalled(t) &&
bt_flag_is_set(t, BTF_SIG_BUDGET_SENT)))) {
TRACE_TASK(t,
"trying to arm timer when budget "
"has already been exhausted.\n");
return;
}
}
TRACE_TASK(t, "arming enforcement timer.\n");
/* __hrtimer_start_range_ns() cancels the timer
* anyway, so we don't have to check whether it is still armed */
raw_spin_lock_irqsave(&et->lock, flags);
if (et->armed) {
TRACE_TASK(t, "timer already armed (race)!\n");
goto out;
}
now = litmus_clock();
remaining_budget = budget_remaining(t);
when_to_fire = now + remaining_budget;
TRACE_TASK(t, "budget remaining: %ld, when_to_fire: %ld\n",
remaining_budget, when_to_fire);
__hrtimer_start_range_ns(&et->timer,
ns_to_ktime(when_to_fire),
0 /* delta */,
HRTIMER_MODE_ABS_PINNED, /* TODO: need to use non-pinned? */
0 /* no wakeup */);
et->armed = 1;
out:
raw_spin_unlock_irqrestore(&et->lock, flags);
}
static enum hrtimer_restart psnedf_simple_on_exhausted(struct task_struct *t, int in_schedule)
{
/* Assumption: t is scheduled on the CPU executing this callback */
if (budget_signalled(t) && !bt_flag_is_set(t, BTF_SIG_BUDGET_SENT)) {
/* signal exhaustion */
send_sigbudget(t); /* will set BTF_SIG_BUDGET_SENT */
}
if (budget_enforced(t) && !bt_flag_test_and_set(t, BTF_BUDGET_EXHAUSTED)) {
if (!is_np(t)) {
/* np tasks will be preempted when they become
* preemptable again
*/
litmus_reschedule_local();
TRACE("%d is preemptable => FORCE_RESCHED\n", t->pid);
} else if (is_user_np(t)) {
TRACE("%d is non-preemptable, preemption delayed.\n", t->pid);
request_exit_np(t);
}
}
return HRTIMER_NORESTART;
}