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path: root/drivers/powercap/idle_inject.c
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Diffstat (limited to 'drivers/powercap/idle_inject.c')
-rw-r--r--drivers/powercap/idle_inject.c65
1 files changed, 57 insertions, 8 deletions
diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index fe86a09e3b67..e18a2cc4e46a 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -63,13 +63,29 @@ struct idle_inject_thread {
* @idle_duration_us: duration of CPU idle time to inject
* @run_duration_us: duration of CPU run time to allow
* @latency_us: max allowed latency
+ * @update: Optional callback deciding whether or not to skip idle
+ * injection in the given cycle.
* @cpumask: mask of CPUs affected by idle injection
+ *
+ * This structure is used to define per instance idle inject device data. Each
+ * instance has an idle duration, a run duration and mask of CPUs to inject
+ * idle.
+ *
+ * Actual CPU idle time is injected by calling kernel scheduler interface
+ * play_idle_precise(). There is one optional callback that can be registered
+ * by calling idle_inject_register_full():
+ *
+ * update() - This callback is invoked just before waking up CPUs to inject
+ * idle. If it returns false, CPUs are not woken up to inject idle in the given
+ * cycle. It also allows the caller to readjust the idle and run duration by
+ * calling idle_inject_set_duration() for the next cycle.
*/
struct idle_inject_device {
struct hrtimer timer;
unsigned int idle_duration_us;
unsigned int run_duration_us;
unsigned int latency_us;
+ bool (*update)(void);
unsigned long cpumask[];
};
@@ -111,11 +127,12 @@ static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *timer)
struct idle_inject_device *ii_dev =
container_of(timer, struct idle_inject_device, timer);
+ if (!ii_dev->update || (ii_dev->update && ii_dev->update()))
+ idle_inject_wakeup(ii_dev);
+
duration_us = READ_ONCE(ii_dev->run_duration_us);
duration_us += READ_ONCE(ii_dev->idle_duration_us);
- idle_inject_wakeup(ii_dev);
-
hrtimer_forward_now(timer, ns_to_ktime(duration_us * NSEC_PER_USEC));
return HRTIMER_RESTART;
@@ -155,11 +172,14 @@ void idle_inject_set_duration(struct idle_inject_device *ii_dev,
unsigned int run_duration_us,
unsigned int idle_duration_us)
{
- if (run_duration_us && idle_duration_us) {
+ if (run_duration_us + idle_duration_us) {
WRITE_ONCE(ii_dev->run_duration_us, run_duration_us);
WRITE_ONCE(ii_dev->idle_duration_us, idle_duration_us);
}
+ if (!run_duration_us)
+ pr_debug("CPU is forced to 100 percent idle\n");
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_set_duration, IDLE_INJECT);
/**
* idle_inject_get_duration - idle and run duration retrieval helper
@@ -174,6 +194,7 @@ void idle_inject_get_duration(struct idle_inject_device *ii_dev,
*run_duration_us = READ_ONCE(ii_dev->run_duration_us);
*idle_duration_us = READ_ONCE(ii_dev->idle_duration_us);
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_get_duration, IDLE_INJECT);
/**
* idle_inject_set_latency - set the maximum latency allowed
@@ -185,6 +206,7 @@ void idle_inject_set_latency(struct idle_inject_device *ii_dev,
{
WRITE_ONCE(ii_dev->latency_us, latency_us);
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_set_latency, IDLE_INJECT);
/**
* idle_inject_start - start idle injections
@@ -201,7 +223,7 @@ int idle_inject_start(struct idle_inject_device *ii_dev)
unsigned int idle_duration_us = READ_ONCE(ii_dev->idle_duration_us);
unsigned int run_duration_us = READ_ONCE(ii_dev->run_duration_us);
- if (!idle_duration_us || !run_duration_us)
+ if (!(idle_duration_us + run_duration_us))
return -EINVAL;
pr_debug("Starting injecting idle cycles on CPUs '%*pbl'\n",
@@ -216,6 +238,7 @@ int idle_inject_start(struct idle_inject_device *ii_dev)
return 0;
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_start, IDLE_INJECT);
/**
* idle_inject_stop - stops idle injections
@@ -262,6 +285,7 @@ void idle_inject_stop(struct idle_inject_device *ii_dev)
cpu_hotplug_enable();
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_stop, IDLE_INJECT);
/**
* idle_inject_setup - prepare the current task for idle injection
@@ -290,17 +314,22 @@ static int idle_inject_should_run(unsigned int cpu)
}
/**
- * idle_inject_register - initialize idle injection on a set of CPUs
+ * idle_inject_register_full - initialize idle injection on a set of CPUs
* @cpumask: CPUs to be affected by idle injection
+ * @update: This callback is called just before waking up CPUs to inject
+ * idle
*
* This function creates an idle injection control device structure for the
- * given set of CPUs and initializes the timer associated with it. It does not
- * start any injection cycles.
+ * given set of CPUs and initializes the timer associated with it. This
+ * function also allows to register update()callback.
+ * It does not start any injection cycles.
*
* Return: NULL if memory allocation fails, idle injection control device
* pointer on success.
*/
-struct idle_inject_device *idle_inject_register(struct cpumask *cpumask)
+
+struct idle_inject_device *idle_inject_register_full(struct cpumask *cpumask,
+ bool (*update)(void))
{
struct idle_inject_device *ii_dev;
int cpu, cpu_rb;
@@ -313,6 +342,7 @@ struct idle_inject_device *idle_inject_register(struct cpumask *cpumask)
hrtimer_init(&ii_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
ii_dev->timer.function = idle_inject_timer_fn;
ii_dev->latency_us = UINT_MAX;
+ ii_dev->update = update;
for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {
@@ -337,6 +367,24 @@ out_rollback:
return NULL;
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_register_full, IDLE_INJECT);
+
+/**
+ * idle_inject_register - initialize idle injection on a set of CPUs
+ * @cpumask: CPUs to be affected by idle injection
+ *
+ * This function creates an idle injection control device structure for the
+ * given set of CPUs and initializes the timer associated with it. It does not
+ * start any injection cycles.
+ *
+ * Return: NULL if memory allocation fails, idle injection control device
+ * pointer on success.
+ */
+struct idle_inject_device *idle_inject_register(struct cpumask *cpumask)
+{
+ return idle_inject_register_full(cpumask, NULL);
+}
+EXPORT_SYMBOL_NS_GPL(idle_inject_register, IDLE_INJECT);
/**
* idle_inject_unregister - unregister idle injection control device
@@ -357,6 +405,7 @@ void idle_inject_unregister(struct idle_inject_device *ii_dev)
kfree(ii_dev);
}
+EXPORT_SYMBOL_NS_GPL(idle_inject_unregister, IDLE_INJECT);
static struct smp_hotplug_thread idle_inject_threads = {
.store = &idle_inject_thread.tsk,