static void __lapic_timer_propagate_broadcast(void *arg)
{
struct acpi_processor *pr = (struct acpi_processor *) arg;
if (pr->power.timer_broadcast_on_state < INT_MAX)
tick_broadcast_enable();
else
tick_broadcast_disable();
}
/* avoid HT sibilings if possible */
if (cpumask_empty(tmp))
cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
if (cpumask_empty(tmp)) {
mutex_unlock(&round_robin_lock);
return;
}
for_each_cpu(cpu, tmp) {
if (cpu_weight[cpu] < min_weight) {
min_weight = cpu_weight[cpu];
preferred_cpu = cpu;
}
}
if (tsk_in_cpu[tsk_index] != -1)
cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
tsk_in_cpu[tsk_index] = preferred_cpu;
cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
cpu_weight[preferred_cpu]++;
mutex_unlock(&round_robin_lock);
set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
}
static void exit_round_robin(unsigned int tsk_index)
{
struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
tsk_in_cpu[tsk_index] = -1;
}
static unsigned int idle_pct = 5; /* percentage */
static unsigned int round_robin_time = 1; /* second */
static int power_saving_thread(void *data)
{
struct sched_param param = {.sched_priority = 1};
int do_sleep;
unsigned int tsk_index = (unsigned long)data;
u64 last_jiffies = 0;
sched_setscheduler(current, SCHED_RR, ¶m);
while (!kthread_should_stop()) {
unsigned long expire_time;
try_to_freeze();
/* round robin to cpus */
expire_time = last_jiffies + round_robin_time * HZ;
if (time_before(expire_time, jiffies)) {
last_jiffies = jiffies;
round_robin_cpu(tsk_index);
}
do_sleep = 0;
expire_time = jiffies + HZ * (100 - idle_pct) / 100;
while (!need_resched()) {
if (tsc_detected_unstable && !tsc_marked_unstable) {
/* TSC could halt in idle, so notify users */
mark_tsc_unstable("TSC halts in idle");
tsc_marked_unstable = 1;
}
local_irq_disable();
tick_broadcast_enable();
tick_broadcast_enter();
stop_critical_timings();
mwait_idle_with_hints(power_saving_mwait_eax, 1);
start_critical_timings();
tick_broadcast_exit();
local_irq_enable();
if (time_before(expire_time, jiffies)) {
do_sleep = 1;
break;
}
}
/*
* current sched_rt has threshold for rt task running time.
* When a rt task uses 95% CPU time, the rt thread will be
* scheduled out for 5% CPU time to not starve other tasks. But
* the mechanism only works when all CPUs have RT task running,
* as if one CPU hasn't RT task, RT task from other CPUs will
* borrow CPU time from this CPU and cause RT task use > 95%
* CPU time. To make 'avoid starvation' work, takes a nap here.
*/
if (unlikely(do_sleep))
schedule_timeout_killable(HZ * idle_pct / 100);
/* If an external event has set the need_resched flag, then
* we need to deal with it, or this loop will continue to
* spin without calling __mwait().
*/
if (unlikely(need_resched()))
schedule();
}
exit_round_robin(tsk_index);
return 0;
}
static struct task_struct *ps_tsks[NR_CPUS];
static unsigned int ps_tsk_num;
static int create_power_saving_task(void)
{
int rc;
ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
(void *)(unsigned long)ps_tsk_num,
"acpi_pad/%d", ps_tsk_num);
if (IS_ERR(ps_tsks[ps_tsk_num])) {
rc = PTR_ERR(ps_tsks[ps_tsk_num]);
ps_tsks[ps_tsk_num] = NULL;
} else {
rc = 0;
ps_tsk_num++;
}
return rc;
}
