* [PATCH] cpuidle: Drop misleading comments about RCU usage
@ 2020-09-22 9:15 ` Ulf Hansson
0 siblings, 0 replies; 4+ messages in thread
From: Ulf Hansson @ 2020-09-22 9:15 UTC (permalink / raw)
To: Rafael J . Wysocki, Daniel Lezcano, linux-pm
Cc: Lina Iyer, Ulf Hansson, linux-arm-kernel, Peter Zijlstra
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(-)
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] cpuidle: Drop misleading comments about RCU usage
@ 2020-09-22 9:15 ` Ulf Hansson
0 siblings, 0 replies; 4+ messages in thread
From: Ulf Hansson @ 2020-09-22 9:15 UTC (permalink / raw)
To: Rafael J . Wysocki, Daniel Lezcano, linux-pm
Cc: Peter Zijlstra, Ulf Hansson, linux-arm-kernel, Lina Iyer
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(-)
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
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] cpuidle: Drop misleading comments about RCU usage
2020-09-22 9:15 ` Ulf Hansson
@ 2020-09-22 17:34 ` Rafael J. Wysocki
-1 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2020-09-22 17:34 UTC (permalink / raw)
To: Ulf Hansson
Cc: Rafael J . Wysocki, Daniel Lezcano, Linux PM, Lina Iyer,
Linux ARM, Peter Zijlstra
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
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cpuidle: Drop misleading comments about RCU usage
@ 2020-09-22 17:34 ` Rafael J. Wysocki
0 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2020-09-22 17:34 UTC (permalink / raw)
To: Ulf Hansson
Cc: Linux PM, Peter Zijlstra, Daniel Lezcano, Rafael J . Wysocki,
Lina Iyer, Linux ARM
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
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-09-22 17:35 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-09-22 9:15 [PATCH] cpuidle: Drop misleading comments about RCU usage Ulf Hansson
2020-09-22 9:15 ` Ulf Hansson
2020-09-22 17:34 ` Rafael J. Wysocki
2020-09-22 17:34 ` Rafael J. Wysocki
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