diff options
| -rw-r--r-- | drivers/thermal/intel_powerclamp.c | 292 |
1 files changed, 170 insertions, 122 deletions
diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_powerclamp.c index 63657d193db5..a94f7c849a4e 100644 --- a/drivers/thermal/intel_powerclamp.c +++ b/drivers/thermal/intel_powerclamp.c @@ -86,11 +86,27 @@ static unsigned int control_cpu; /* The cpu assigned to collect stat and update */ static bool clamping; +static const struct sched_param sparam = { + .sched_priority = MAX_USER_RT_PRIO / 2, +}; +struct powerclamp_worker_data { + struct kthread_worker *worker; + struct kthread_work balancing_work; + struct kthread_delayed_work idle_injection_work; + struct timer_list wakeup_timer; + unsigned int cpu; + unsigned int count; + unsigned int guard; + unsigned int window_size_now; + unsigned int target_ratio; + unsigned int duration_jiffies; + bool clamping; +}; -static struct task_struct * __percpu *powerclamp_thread; +static struct powerclamp_worker_data * __percpu worker_data; static struct thermal_cooling_device *cooling_dev; static unsigned long *cpu_clamping_mask; /* bit map for tracking per cpu - * clamping thread + * clamping kthread worker */ static unsigned int duration; @@ -368,103 +384,104 @@ static bool powerclamp_adjust_controls(unsigned int target_ratio, return set_target_ratio + guard <= current_ratio; } -static int clamp_thread(void *arg) +static void clamp_balancing_func(struct kthread_work *work) { - int cpunr = (unsigned long)arg; - DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0); - static const struct sched_param param = { - .sched_priority = MAX_USER_RT_PRIO/2, - }; - unsigned int count = 0; - unsigned int target_ratio; + struct powerclamp_worker_data *w_data; + int sleeptime; + unsigned long target_jiffies; + unsigned int compensated_ratio; + int interval; /* jiffies to sleep for each attempt */ - set_bit(cpunr, cpu_clamping_mask); - set_freezable(); - init_timer_on_stack(&wakeup_timer); - sched_setscheduler(current, SCHED_FIFO, ¶m); - - while (true == clamping && !kthread_should_stop() && - cpu_online(cpunr)) { - int sleeptime; - unsigned long target_jiffies; - unsigned int guard; - unsigned int compensated_ratio; - int interval; /* jiffies to sleep for each attempt */ - unsigned int duration_jiffies = msecs_to_jiffies(duration); - unsigned int window_size_now; - - try_to_freeze(); - /* - * make sure user selected ratio does not take effect until - * the next round. adjust target_ratio if user has changed - * target such that we can converge quickly. - */ - target_ratio = set_target_ratio; - guard = 1 + target_ratio/20; - window_size_now = window_size; - count++; + w_data = container_of(work, struct powerclamp_worker_data, + balancing_work); - /* - * systems may have different ability to enter package level - * c-states, thus we need to compensate the injected idle ratio - * to achieve the actual target reported by the HW. - */ - compensated_ratio = target_ratio + - get_compensation(target_ratio); - if (compensated_ratio <= 0) - compensated_ratio = 1; - interval = duration_jiffies * 100 / compensated_ratio; - - /* align idle time */ - target_jiffies = roundup(jiffies, interval); - sleeptime = target_jiffies - jiffies; - if (sleeptime <= 0) - sleeptime = 1; - schedule_timeout_interruptible(sleeptime); - /* - * only elected controlling cpu can collect stats and update - * control parameters. - */ - if (cpunr == control_cpu && !(count%window_size_now)) { - should_skip = - powerclamp_adjust_controls(target_ratio, - guard, window_size_now); - smp_mb(); - } + /* + * make sure user selected ratio does not take effect until + * the next round. adjust target_ratio if user has changed + * target such that we can converge quickly. + */ + w_data->target_ratio = READ_ONCE(set_target_ratio); + w_data->guard = 1 + w_data->target_ratio / 20; + w_data->window_size_now = window_size; + w_data->duration_jiffies = msecs_to_jiffies(duration); + w_data->count++; + + /* + * systems may have different ability to enter package level + * c-states, thus we need to compensate the injected idle ratio + * to achieve the actual target reported by the HW. + */ + compensated_ratio = w_data->target_ratio + + get_compensation(w_data->target_ratio); + if (compensated_ratio <= 0) + compensated_ratio = 1; + interval = w_data->duration_jiffies * 100 / compensated_ratio; + + /* align idle time */ + target_jiffies = roundup(jiffies, interval); + sleeptime = target_jiffies - jiffies; + if (sleeptime <= 0) + sleeptime = 1; + + if (clamping && w_data->clamping && cpu_online(w_data->cpu)) + kthread_queue_delayed_work(w_data->worker, + &w_data->idle_injection_work, + sleeptime); +} + +static void clamp_idle_injection_func(struct kthread_work *work) +{ + struct powerclamp_worker_data *w_data; + unsigned long target_jiffies; + + w_data = container_of(work, struct powerclamp_worker_data, + idle_injection_work.work); + + /* + * only elected controlling cpu can collect stats and update + * control parameters. + */ + if (w_data->cpu == control_cpu && + !(w_data->count % w_data->window_size_now)) { + should_skip = + powerclamp_adjust_controls(w_data->target_ratio, + w_data->guard, + w_data->window_size_now); + smp_mb(); + } - if (should_skip) - continue; + if (should_skip) + goto balance; + + target_jiffies = jiffies + w_data->duration_jiffies; + mod_timer(&w_data->wakeup_timer, target_jiffies); + if (unlikely(local_softirq_pending())) + goto balance; + /* + * stop tick sched during idle time, interrupts are still + * allowed. thus jiffies are updated properly. + */ + preempt_disable(); + /* mwait until target jiffies is reached */ + while (time_before(jiffies, target_jiffies)) { + unsigned long ecx = 1; + unsigned long eax = target_mwait; - target_jiffies = jiffies + duration_jiffies; - mod_timer(&wakeup_timer, target_jiffies); - if (unlikely(local_softirq_pending())) - continue; /* - * stop tick sched during idle time, interrupts are still - * allowed. thus jiffies are updated properly. + * REVISIT: may call enter_idle() to notify drivers who + * can save power during cpu idle. same for exit_idle() */ - preempt_disable(); - /* mwait until target jiffies is reached */ - while (time_before(jiffies, target_jiffies)) { - unsigned long ecx = 1; - unsigned long eax = target_mwait; - - /* - * REVISIT: may call enter_idle() to notify drivers who - * can save power during cpu idle. same for exit_idle() - */ - local_touch_nmi(); - stop_critical_timings(); - mwait_idle_with_hints(eax, ecx); - start_critical_timings(); - atomic_inc(&idle_wakeup_counter); - } - preempt_enable(); + local_touch_nmi(); + stop_critical_timings(); + mwait_idle_with_hints(eax, ecx); + start_critical_timings(); + atomic_inc(&idle_wakeup_counter); } - del_timer_sync(&wakeup_timer); - clear_bit(cpunr, cpu_clamping_mask); + preempt_enable(); - return 0; +balance: + if (clamping && w_data->clamping && cpu_online(w_data->cpu)) + kthread_queue_work(w_data->worker, &w_data->balancing_work); } /* @@ -508,22 +525,58 @@ static void poll_pkg_cstate(struct work_struct *dummy) schedule_delayed_work(&poll_pkg_cstate_work, HZ); } -static void start_power_clamp_thread(unsigned long cpu) +static void start_power_clamp_worker(unsigned long cpu) { - struct task_struct **p = per_cpu_ptr(powerclamp_thread, cpu); - struct task_struct *thread; - - thread = kthread_create_on_node(clamp_thread, - (void *) cpu, - cpu_to_node(cpu), - "kidle_inject/%ld", cpu); - if (IS_ERR(thread)) + struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu); + struct kthread_worker *worker; + + worker = kthread_create_worker_on_cpu(cpu, KTW_FREEZABLE, + "kidle_inject/%ld", cpu); + if (IS_ERR(worker)) return; - /* bind to cpu here */ - kthread_bind(thread, cpu); - wake_up_process(thread); - *p = thread; + w_data->worker = worker; + w_data->count = 0; + w_data->cpu = cpu; + w_data->clamping = true; + set_bit(cpu, cpu_clamping_mask); + setup_timer(&w_data->wakeup_timer, noop_timer, 0); + sched_setscheduler(worker->task, SCHED_FIFO, &sparam); + kthread_init_work(&w_data->balancing_work, clamp_balancing_func); + kthread_init_delayed_work(&w_data->idle_injection_work, + clamp_idle_injection_func); + kthread_queue_work(w_data->worker, &w_data->balancing_work); +} + +static void stop_power_clamp_worker(unsigned long cpu) +{ + struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu); + + if (!w_data->worker) + return; + + w_data->clamping = false; + /* + * Make sure that all works that get queued after this point see + * the clamping disabled. The counter part is not needed because + * there is an implicit memory barrier when the queued work + * is proceed. + */ + smp_wmb(); + kthread_cancel_work_sync(&w_data->balancing_work); + kthread_cancel_delayed_work_sync(&w_data->idle_injection_work); + /* + * The balancing work still might be queued here because + * the handling of the "clapming" variable, cancel, and queue + * operations are not synchronized via a lock. But it is not + * a big deal. The balancing work is fast and destroy kthread + * will wait for it. + */ + del_timer_sync(&w_data->wakeup_timer); + clear_bit(w_data->cpu, cpu_clamping_mask); + kthread_destroy_worker(w_data->worker); + + w_data->worker = NULL; } static int start_power_clamp(void) @@ -542,9 +595,9 @@ static int start_power_clamp(void) clamping = true; schedule_delayed_work(&poll_pkg_cstate_work, 0); - /* start one thread per online cpu */ + /* start one kthread worker per online cpu */ for_each_online_cpu(cpu) { - start_power_clamp_thread(cpu); + start_power_clamp_worker(cpu); } put_online_cpus(); @@ -554,20 +607,17 @@ static int start_power_clamp(void) static void end_power_clamp(void) { int i; - struct task_struct *thread; - clamping = false; /* - * make clamping visible to other cpus and give per cpu clamping threads - * sometime to exit, or gets killed later. + * Block requeuing in all the kthread workers. They will flush and + * stop faster. */ - smp_mb(); - msleep(20); + clamping = false; if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) { for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) { - pr_debug("clamping thread for cpu %d alive, kill\n", i); - thread = *per_cpu_ptr(powerclamp_thread, i); - kthread_stop(thread); + pr_debug("clamping worker for cpu %d alive, destroy\n", + i); + stop_power_clamp_worker(i); } } } @@ -576,15 +626,13 @@ static int powerclamp_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned long cpu = (unsigned long)hcpu; - struct task_struct **percpu_thread = - per_cpu_ptr(powerclamp_thread, cpu); if (false == clamping) goto exit_ok; switch (action) { case CPU_ONLINE: - start_power_clamp_thread(cpu); + start_power_clamp_worker(cpu); /* prefer BSP as controlling CPU */ if (cpu == 0) { control_cpu = 0; @@ -595,7 +643,7 @@ static int powerclamp_cpu_callback(struct notifier_block *nfb, if (test_bit(cpu, cpu_clamping_mask)) { pr_err("cpu %lu dead but powerclamping thread is not\n", cpu); - kthread_stop(*percpu_thread); + stop_power_clamp_worker(cpu); } if (cpu == control_cpu) { control_cpu = smp_processor_id(); @@ -759,8 +807,8 @@ static int __init powerclamp_init(void) window_size = 2; register_hotcpu_notifier(&powerclamp_cpu_notifier); - powerclamp_thread = alloc_percpu(struct task_struct *); - if (!powerclamp_thread) { + worker_data = alloc_percpu(struct powerclamp_worker_data); + if (!worker_data) { retval = -ENOMEM; goto exit_unregister; } @@ -780,7 +828,7 @@ static int __init powerclamp_init(void) return 0; exit_free_thread: - free_percpu(powerclamp_thread); + free_percpu(worker_data); exit_unregister: unregister_hotcpu_notifier(&powerclamp_cpu_notifier); exit_free: @@ -793,7 +841,7 @@ static void __exit powerclamp_exit(void) { unregister_hotcpu_notifier(&powerclamp_cpu_notifier); end_power_clamp(); - free_percpu(powerclamp_thread); + free_percpu(worker_data); thermal_cooling_device_unregister(cooling_dev); kfree(cpu_clamping_mask); |