cpuidle: add poll_limit_ns to cpuidle_device structure

Add a poll_limit_ns variable to cpuidle_device structure.

Calculate and configure it in the new cpuidle_poll_time
function, in case its zero.

Individual governors are allowed to override this value.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpuidle/cpuidle.c

@@ -361,6 +361,36 @@ void cpuidle_reflect(struct cpuidle_device *dev, int index)
 		cpuidle_curr_governor->reflect(dev, index);
 }
 
+/**
+ * cpuidle_poll_time - return amount of time to poll for,
+ * governors can override dev->poll_limit_ns if necessary
+ *
+ * @drv:   the cpuidle driver tied with the cpu
+ * @dev:   the cpuidle device
+ *
+ */
+u64 cpuidle_poll_time(struct cpuidle_driver *drv,
+		      struct cpuidle_device *dev)
+{
+	int i;
+	u64 limit_ns;
+
+	if (dev->poll_limit_ns)
+		return dev->poll_limit_ns;
+
+	limit_ns = TICK_NSEC;
+	for (i = 1; i < drv->state_count; i++) {
+		if (drv->states[i].disabled || dev->states_usage[i].disable)
+			continue;
+
+		limit_ns = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
+	}
+
+	dev->poll_limit_ns = limit_ns;
+
+	return dev->poll_limit_ns;
+}
+
 /**
  * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
  */

drivers/cpuidle/poll_state.c

@@ -20,16 +20,9 @@ static int __cpuidle poll_idle(struct cpuidle_device *dev,
 	local_irq_enable();
 	if (!current_set_polling_and_test()) {
 		unsigned int loop_count = 0;
-		u64 limit = TICK_NSEC;
+		u64 limit;
-		int i;
 
-		for (i = 1; i < drv->state_count; i++) {
+		limit = cpuidle_poll_time(drv, dev);
-			if (drv->states[i].disabled || dev->states_usage[i].disable)
-				continue;
-
-			limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
-			break;
-		}
 
 		while (!need_resched()) {
 			cpu_relax();

drivers/cpuidle/sysfs.c

@@ -334,6 +334,7 @@ struct cpuidle_state_kobj {
 	struct cpuidle_state_usage *state_usage;
 	struct completion kobj_unregister;
 	struct kobject kobj;
+	struct cpuidle_device *device;
 };
 
 #ifdef CONFIG_SUSPEND
@@ -391,6 +392,7 @@ static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *k
 #define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
 #define kobj_to_state(k) (kobj_to_state_obj(k)->state)
 #define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
+#define kobj_to_device(k) (kobj_to_state_obj(k)->device)
 #define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
 
 static ssize_t cpuidle_state_show(struct kobject *kobj, struct attribute *attr,
@@ -414,10 +416,14 @@ static ssize_t cpuidle_state_store(struct kobject *kobj, struct attribute *attr,
 	struct cpuidle_state *state = kobj_to_state(kobj);
 	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
 	struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
+	struct cpuidle_device *dev = kobj_to_device(kobj);
 
 	if (cattr->store)
 		ret = cattr->store(state, state_usage, buf, size);
 
+	/* reset poll time cache */
+	dev->poll_limit_ns = 0;
+
 	return ret;
 }
 
@@ -468,6 +474,7 @@ static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
 		}
 		kobj->state = &drv->states[i];
 		kobj->state_usage = &device->states_usage[i];
+		kobj->device = device;
 		init_completion(&kobj->kobj_unregister);
 
 		ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle,

include/linux/cpuidle.h

@@ -86,6 +86,7 @@ struct cpuidle_device {
 	ktime_t			next_hrtimer;
 
 	int			last_residency;
+	u64			poll_limit_ns;
 	struct cpuidle_state_usage	states_usage[CPUIDLE_STATE_MAX];
 	struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
 	struct cpuidle_driver_kobj *kobj_driver;
@@ -132,6 +133,8 @@ extern int cpuidle_select(struct cpuidle_driver *drv,
 extern int cpuidle_enter(struct cpuidle_driver *drv,
 			 struct cpuidle_device *dev, int index);
 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
+extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
+			     struct cpuidle_device *dev);
 
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 extern struct cpuidle_driver *cpuidle_get_driver(void);
@@ -166,6 +169,9 @@ static inline int cpuidle_enter(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev, int index)
 {return -ENODEV; }
 static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
+extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
+			     struct cpuidle_device *dev)
+{return 0; }
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }
 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }