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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-09 22:59:49 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-07-09 22:59:49 +0200
commitae0afb4f5d44d17a0fd135ae000e2acf12c53617 (patch)
tree35b7a32ed8fc9d2b6ca219e3b4769f7fb165c455
parentd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (diff)
downloadarm64-stable-rc-ae0afb4f5d44d17a0fd135ae000e2acf12c53617.tar.gz
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 <rafael.j.wysocki@intel.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--drivers/cpuidle/cpuidle.c9
1 files 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());