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

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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 <rafael.j.wysocki@intel.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Rafael J. Wysocki 2015-07-09 22:59:49 +02:00
parent d770e558e2
commit ae0afb4f5d
1 changed files with 7 additions and 2 deletions
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9
drivers/cpuidle/cpuidle.c
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@ -112,7 +112,12 @@ int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
static void enter_freeze_proper(struct cpuidle_driver *drv, static void enter_freeze_proper(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index) 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" * The state used here cannot be a "coupled" one, because the "coupled"
* cpuidle mechanism enables interrupts and doing that with timekeeping * 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()); WARN_ON(!irqs_disabled());
/* /*
* timekeeping_resume() that will be called by tick_unfreeze() for the * 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. * critical sections, so tell RCU about that.
*/ */
RCU_NONIDLE(tick_unfreeze()); RCU_NONIDLE(tick_unfreeze());