diff mbox series

cpuidle: Drop misleading comments about RCU usage

Message ID 20200922091550.90191-1-ulf.hansson@linaro.org
State New
Headers show
Series cpuidle: Drop misleading comments about RCU usage | expand

Commit Message

Ulf Hansson Sept. 22, 2020, 9:15 a.m. UTC
The commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the
idle path"), moved the calls rcu_idle_enter|exit() into the cpuidle core.

However, it forgot to remove a couple of comments in enter_s2idle_proper()
about why RCU_NONIDLE earlier was needed. So, let's drop them as they have
become a bit misleading.

Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/cpuidle/cpuidle.c | 10 ----------
 1 file changed, 10 deletions(-)

Comments

Rafael J. Wysocki Sept. 22, 2020, 5:34 p.m. UTC | #1
On Tue, Sep 22, 2020 at 11:16 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>

> The commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the

> idle path"), moved the calls rcu_idle_enter|exit() into the cpuidle core.

>

> However, it forgot to remove a couple of comments in enter_s2idle_proper()

> about why RCU_NONIDLE earlier was needed. So, let's drop them as they have

> become a bit misleading.

>

> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>

> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>


Applied as 5.9-rc7 material, thanks!

> ---

>  drivers/cpuidle/cpuidle.c | 10 ----------

>  1 file changed, 10 deletions(-)

>

> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c

> index 6c7e5621cf9a..29e84687f3c3 100644

> --- a/drivers/cpuidle/cpuidle.c

> +++ b/drivers/cpuidle/cpuidle.c

> @@ -142,11 +142,6 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv,

>

>         time_start = ns_to_ktime(local_clock());

>

> -       /*

> -        * 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.

> -        */

>         tick_freeze();

>         /*

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

> @@ -159,11 +154,6 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv,

>         target_state->enter_s2idle(dev, drv, index);

>         if (WARN_ON_ONCE(!irqs_disabled()))

>                 local_irq_disable();

> -       /*

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

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

> -        * critical sections, so tell RCU about that.

> -        */

>         if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))

>                 rcu_idle_exit();

>         tick_unfreeze();

> --

> 2.25.1

>
diff mbox series

Patch

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 6c7e5621cf9a..29e84687f3c3 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -142,11 +142,6 @@  static void enter_s2idle_proper(struct cpuidle_driver *drv,
 
 	time_start = ns_to_ktime(local_clock());
 
-	/*
-	 * 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.
-	 */
 	tick_freeze();
 	/*
 	 * The state used here cannot be a "coupled" one, because the "coupled"
@@ -159,11 +154,6 @@  static void enter_s2idle_proper(struct cpuidle_driver *drv,
 	target_state->enter_s2idle(dev, drv, index);
 	if (WARN_ON_ONCE(!irqs_disabled()))
 		local_irq_disable();
-	/*
-	 * timekeeping_resume() that will be called by tick_unfreeze() for the
-	 * first CPU executing it calls functions containing RCU read-side
-	 * critical sections, so tell RCU about that.
-	 */
 	if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE))
 		rcu_idle_exit();
 	tick_unfreeze();