cpuidle: Use wake_up_all_idle_cpus() to wake up all idle cpus

Currently kick_all_cpus_sync() or smp_call_function() can not
break the polling idle cpu immediately.

Instead using wake_up_all_idle_cpus() which can wake up the polling idle
cpu quickly is much more helpful for power.

Signed-off-by: Chuansheng Liu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Daniel Lezcano <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

drivers/cpuidle/cpuidle.c

@@ -223,7 +223,7 @@ void cpuidle_uninstall_idle_handler(void)
 {
 	if (enabled_devices) {
 		initialized = 0;
-		kick_all_cpus_sync();
+		wake_up_all_idle_cpus();
 	}
 }
 
@@ -530,11 +530,6 @@ EXPORT_SYMBOL_GPL(cpuidle_register);
 
 #ifdef CONFIG_SMP
 
-static void smp_callback(void *v)
-{
-	/* we already woke the CPU up, nothing more to do */
-}
-
 /*
  * This function gets called when a part of the kernel has a new latency
  * requirement.  This means we need to get all processors out of their C-state,
@@ -544,7 +539,7 @@ static void smp_callback(void *v)
 static int cpuidle_latency_notify(struct notifier_block *b,
 		unsigned long l, void *v)
 {
-	smp_call_function(smp_callback, NULL, 1);
+	wake_up_all_idle_cpus();
 	return NOTIFY_OK;
 }