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-rw-r--r--kernel/time/tick-sched.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index ce89ffb474d0..10a1347597fd 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -153,6 +153,7 @@ void tick_nohz_stop_sched_tick(void)
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
struct tick_sched *ts;
ktime_t last_update, expires, now, delta;
+ struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
int cpu;
local_irq_save(flags);
@@ -302,11 +303,26 @@ void tick_nohz_stop_sched_tick(void)
out:
ts->next_jiffies = next_jiffies;
ts->last_jiffies = last_jiffies;
+ ts->sleep_length = ktime_sub(dev->next_event, now);
end:
local_irq_restore(flags);
}
/**
+ * tick_nohz_get_sleep_length - return the length of the current sleep
+ *
+ * Called from power state control code with interrupts disabled
+ */
+ktime_t tick_nohz_get_sleep_length(void)
+{
+ struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
+
+ return ts->sleep_length;
+}
+
+EXPORT_SYMBOL_GPL(tick_nohz_get_sleep_length);
+
+/**
* nohz_restart_sched_tick - restart the idle tick from the idle task
*
* Restart the idle tick when the CPU is woken up from idle