/*
* Shared reprogramming for clock_realtime and clock_monotonic
*
* When a timer is enqueued and expires earlier than the already enqueued
* timers, we have to check, whether it expires earlier than the timer for
* which the clock event device was armed.
*
* Called with interrupts disabled and base->cpu_base.lock held
*/
static int hrtimer_reprogram(struct hrtimer *timer,
struct hrtimer_clock_base *base)
{
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
int res;
WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
/*
* When the callback is running, we do not reprogram the clock event
* device. The timer callback is either running on a different CPU or
* the callback is executed in the hrtimer_interrupt context. The
* reprogramming is handled either by the softirq, which called the
* callback or at the end of the hrtimer_interrupt.
*/
if (hrtimer_callback_running(timer))
return 0;
/*
* CLOCK_REALTIME timer might be requested with an absolute
* expiry time which is less than base->offset. Nothing wrong
* about that, just avoid to call into the tick code, which
* has now objections against negative expiry values.
*/
if (expires.tv64 < 0)
return -ETIME;
if (expires.tv64 >= cpu_base->expires_next.tv64)
return 0;
/*
* If a hang was detected in the last timer interrupt then we
* do not schedule a timer which is earlier than the expiry
* which we enforced in the hang detection. We want the system
* to make progress.
*/
if (cpu_base->hang_detected)
return 0;
/*
* Clockevents returns -ETIME, when the event was in the past.
*/
res = tick_program_event(expires, 0);
if (!IS_ERR_VALUE(res))
cpu_base->expires_next = expires;
return res;
}
/*
* Switch the timer base to the current CPU when possible.
*/
static inline struct hrtimer_clock_base *
switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
int pinned)
{
struct hrtimer_clock_base *new_base;
struct hrtimer_cpu_base *new_cpu_base;
int this_cpu = smp_processor_id();
int cpu = hrtimer_get_target(this_cpu, pinned);
int basenum = base->index;
again:
new_cpu_base = &per_cpu(hrtimer_bases, cpu);
new_base = &new_cpu_base->clock_base[basenum];
if (base != new_base) {
/*
* We are trying to move timer to new_base.
* However we can't change timer's base while it is running,
* so we keep it on the same CPU. No hassle vs. reprogramming
* the event source in the high resolution case. The softirq
* code will take care of this when the timer function has
* completed. There is no conflict as we hold the lock until
* the timer is enqueued.
*/
if (unlikely(hrtimer_callback_running(timer)))
return base;
/* See the comment in lock_timer_base() */
timer->base = NULL;
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);
if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
cpu = this_cpu;
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
timer->base = base;
goto again;
}
timer->base = new_base;
} else {
if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
cpu = this_cpu;
goto again;
}
}
return new_base;
}
/**
* hrtimer_try_to_cancel - try to deactivate a timer
* @timer: hrtimer to stop
*
* Returns:
* 0 when the timer was not active
* 1 when the timer was active
* -1 when the timer is currently excuting the callback function and
* cannot be stopped
*/
int hrtimer_try_to_cancel(struct hrtimer *timer)
{
struct hrtimer_clock_base *base;
unsigned long flags;
int ret = -1;
base = lock_hrtimer_base(timer, &flags);
if (!hrtimer_callback_running(timer))
ret = remove_hrtimer(timer, base);
unlock_hrtimer_base(timer, &flags);
return ret;
}
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
struct rb_node *node;
while ((node = rb_first(&old_base->active))) {
timer = rb_entry(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
__remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
timer->base = new_base;
/*
* Enqueue the timer. Allow reprogramming of the event device
*/
enqueue_hrtimer(timer, new_base, 1);
}
}
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
struct timerqueue_node *node;
while ((node = timerqueue_getnext(&old_base->active))) {
timer = container_of(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
debug_deactivate(timer);
__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
timer->base = new_base;
enqueue_hrtimer(timer, new_base);
timer->state &= ~HRTIMER_STATE_MIGRATE;
}
}
void sobliv_on_exit_top_m(struct task_struct* t)
{
if (budget_precisely_tracked(t)) {
if (tsk_rt(t)->budget.timer.armed) {
if (!is_running(t)) {
/* the time at which we started draining budget while
* suspended is recorded in evt_timestamp. evt_timestamp
* was set either when 't' exited the top-m while suspended
* or when 't' blocked. */
lt_t suspend_cost;
BUG_ON(!tsk_rt(t)->budget.suspend_timestamp);
suspend_cost = litmus_clock() -
tsk_rt(t)->budget.suspend_timestamp;
TRACE_TASK(t, "budget consumed while suspended: %llu\n",
suspend_cost);
get_exec_time(t) += suspend_cost;
/* timer should have fired before now */
if (get_exec_time(t) + 1000000/10 > get_exec_cost(t)) {
TRACE_TASK(t,
"budget overrun while suspended by over 1/10 "
"millisecond! timer should have already fired!\n");
WARN_ON(1);
}
}
TRACE_TASK(t, "stops draining budget\n");
/* the callback will handle it if it is executing */
if (!hrtimer_callback_running(&tsk_rt(t)->budget.timer.timer)) {
/* TODO: record a timestamp if the task isn't running */
cancel_enforcement_timer(t);
}
else {
TRACE_TASK(t,
"within callback context. skipping operation.\n");
}
}
else {
TRACE_TASK(t, "was not draining budget\n");
}
}
}
/*
* Shared reprogramming for clock_realtime and clock_monotonic
*
* When a timer is enqueued and expires earlier than the already enqueued
* timers, we have to check, whether it expires earlier than the timer for
* which the clock event device was armed.
*
* Called with interrupts disabled and base->cpu_base.lock held
*/
static int hrtimer_reprogram(struct hrtimer *timer,
struct hrtimer_clock_base *base)
{
ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
ktime_t expires = ktime_sub(timer->expires, base->offset);
int res;
WARN_ON_ONCE(timer->expires.tv64 < 0);
/*
* When the callback is running, we do not reprogram the clock event
* device. The timer callback is either running on a different CPU or
* the callback is executed in the hrtimer_interrupt context. The
* reprogramming is handled either by the softirq, which called the
* callback or at the end of the hrtimer_interrupt.
*/
if (hrtimer_callback_running(timer))
return 0;
/*
* CLOCK_REALTIME timer might be requested with an absolute
* expiry time which is less than base->offset. Nothing wrong
* about that, just avoid to call into the tick code, which
* has now objections against negative expiry values.
*/
if (expires.tv64 < 0)
return -ETIME;
if (expires.tv64 >= expires_next->tv64)
return 0;
/*
* Clockevents returns -ETIME, when the event was in the past.
*/
res = tick_program_event(expires, 0);
if (!IS_ERR_VALUE(res))
*expires_next = expires;
return res;
}
void sobliv_on_enter_top_m(struct task_struct* t)
{
if (!bt_flag_is_set(t, BTF_SIG_BUDGET_SENT)) {
if (tsk_rt(t)->budget.timer.armed)
TRACE_TASK(t, "budget timer already armed.\n");
else {
/* if we're blocked, then record the time at which we
started measuring */
if (!is_running(t))
tsk_rt(t)->budget.suspend_timestamp = litmus_clock();
/* the callback will handle it if it is executing */
if (!hrtimer_callback_running(&tsk_rt(t)->budget.timer.timer)) {
arm_enforcement_timer(t, 0);
}
else {
TRACE_TASK(t,
"within callback context. deferring timer arm.\n");
}
}
}
}
static inline struct hrtimer_clock_base *
switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
int pinned)
{
struct hrtimer_clock_base *new_base;
struct hrtimer_cpu_base *new_cpu_base;
int this_cpu = smp_processor_id();
int cpu = hrtimer_get_target(this_cpu, pinned);
int basenum = base->index;
again:
new_cpu_base = &per_cpu(hrtimer_bases, cpu);
new_base = &new_cpu_base->clock_base[basenum];
if (base != new_base) {
if (unlikely(hrtimer_callback_running(timer)))
return base;
timer->base = NULL;
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);
this_cpu = smp_processor_id();
if (cpu != this_cpu && (hrtimer_check_target(timer, new_base)
|| !cpu_online(cpu))) {
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
cpu = smp_processor_id();
timer->base = base;
goto again;
}
timer->base = new_base;
}
return new_base;
}
