From ae0afb4f5d44d17a0fd135ae000e2acf12c53617 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 9 Jul 2015 22:59:49 +0200 Subject: [PATCH] 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: Rafael J. Wysocki Reviewed-by: Paul E. McKenney --- drivers/cpuidle/cpuidle.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index e8e2775c3821..48b7228563ad 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -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()); -- 2.25.1