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Commit ae0afb4f authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

suspend-to-idle: Prevent RCU from complaining about tick_freeze() 



Put tick_freeze() under RCU_NONIDLE() to prevent RCU from complaining
about suspicious RCU usage in idle by trace_suspend_resume() called
from there.

While at it, fix a comment related to another usage of RCU_NONIDLE()
in enter_freeze_proper().

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent d770e558

drivers/cpuidle/cpuidle.c

+7 −2
Original line number Diff line number Diff line
@@ -112,7 +112,12 @@ int cpuidle_find_deepest_state(struct cpuidle_driver *drv, 
static void enter_freeze_proper(struct cpuidle_driver *drv,

				struct cpuidle_device *dev, int index)

{

	tick_freeze();

	/*

	 * trace_suspend_resume() called by tick_freeze() for the last CPU

	 * executing it contains RCU usage regarded as invalid in the idle

	 * context, so tell RCU about that.

	 */

	RCU_NONIDLE(tick_freeze());

	/*

	 * The state used here cannot be a "coupled" one, because the "coupled"

	 * cpuidle mechanism enables interrupts and doing that with timekeeping
@@ -122,7 +127,7 @@ static void enter_freeze_proper(struct cpuidle_driver *drv, 
	WARN_ON(!irqs_disabled());

	/*

	 * timekeeping_resume() that will be called by tick_unfreeze() for the

	 * last CPU executing it calls functions containing RCU read-side

	 * first CPU executing it calls functions containing RCU read-side

	 * critical sections, so tell RCU about that.

	 */

	RCU_NONIDLE(tick_unfreeze());