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-rw-r--r--drivers/cpuidle/cpuidle.c19
-rw-r--r--include/linux/cpuidle.h1
-rw-r--r--include/linux/tick.h7
-rw-r--r--kernel/time/tick-sched.c12
4 files changed, 36 insertions, 3 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 7f108309e871..0f4b7c45df3e 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -328,9 +328,23 @@ int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
int index)
{
+ int ret = 0;
+
+ /*
+ * Store the next hrtimer, which becomes either next tick or the next
+ * timer event, whatever expires first. Additionally, to make this data
+ * useful for consumers outside cpuidle, we rely on that the governor's
+ * ->select() callback have decided, whether to stop the tick or not.
+ */
+ WRITE_ONCE(dev->next_hrtimer, tick_nohz_get_next_hrtimer());
+
if (cpuidle_state_is_coupled(drv, index))
- return cpuidle_enter_state_coupled(dev, drv, index);
- return cpuidle_enter_state(dev, drv, index);
+ ret = cpuidle_enter_state_coupled(dev, drv, index);
+ else
+ ret = cpuidle_enter_state(dev, drv, index);
+
+ WRITE_ONCE(dev->next_hrtimer, 0);
+ return ret;
}
/**
@@ -511,6 +525,7 @@ static void __cpuidle_device_init(struct cpuidle_device *dev)
{
memset(dev->states_usage, 0, sizeof(dev->states_usage));
dev->last_residency = 0;
+ dev->next_hrtimer = 0;
}
/**
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 3b39472324a3..bb9a0db89f1a 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -83,6 +83,7 @@ struct cpuidle_device {
unsigned int use_deepest_state:1;
unsigned int poll_time_limit:1;
unsigned int cpu;
+ ktime_t next_hrtimer;
int last_residency;
struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
diff --git a/include/linux/tick.h b/include/linux/tick.h
index 55388ab45fd4..8891b5ac3e40 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -122,6 +122,7 @@ extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern bool tick_nohz_idle_got_tick(void);
+extern ktime_t tick_nohz_get_next_hrtimer(void);
extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next);
extern unsigned long tick_nohz_get_idle_calls(void);
extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu);
@@ -145,7 +146,11 @@ static inline void tick_nohz_idle_restart_tick(void) { }
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
static inline bool tick_nohz_idle_got_tick(void) { return false; }
-
+static inline ktime_t tick_nohz_get_next_hrtimer(void)
+{
+ /* Next wake up is the tick period, assume it starts now */
+ return ktime_add(ktime_get(), TICK_NSEC);
+}
static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
{
*delta_next = TICK_NSEC;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 6fa52cd6df0b..8d18e03124ff 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1023,6 +1023,18 @@ bool tick_nohz_idle_got_tick(void)
}
/**
+ * tick_nohz_get_next_hrtimer - return the next expiration time for the hrtimer
+ * or the tick, whatever that expires first. Note that, if the tick has been
+ * stopped, it returns the next hrtimer.
+ *
+ * Called from power state control code with interrupts disabled
+ */
+ktime_t tick_nohz_get_next_hrtimer(void)
+{
+ return __this_cpu_read(tick_cpu_device.evtdev)->next_event;
+}
+
+/**
* tick_nohz_get_sleep_length - return the expected length of the current sleep
* @delta_next: duration until the next event if the tick cannot be stopped
*