Re: [PATCH v2 10/44] cpuidle,armada: Push RCU-idle into driver

[Frederic Weisbecker]

On Mon, Sep 19, 2022 at 11:59:49AM +0200, Peter Zijlstra wrote:
> Doing RCU-idle outside the driver, only to then temporarily enable it
> again before going idle is daft.

Ah wait, now I see, that's cpu_pm_enter()/cpu_pm_exit() -> cpu_pm_notify*() the 
culprits.
Might be worth adding a short note about that on your changelogs.

> 
> Signed-off-by: Peter Zijlstra (Intel) 
> ---
>  drivers/cpuidle/cpuidle-mvebu-v7.c |7 +++
>  1 file changed, 7 insertions(+)
> 
> --- a/drivers/cpuidle/cpuidle-mvebu-v7.c
> +++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
> @@ -36,7 +36,10 @@ static int mvebu_v7_enter_idle(struct cp
>   if (drv->states[index].flags & MVEBU_V7_FLAG_DEEP_IDLE)
>   deepidle = true;
>  
> + ct_idle_enter();
>   ret = mvebu_v7_cpu_suspend(deepidle);
> + ct_idle_exit();

And then yes of course:

Reviewed-by: Frederic Weisbecker 

[PATCH v2 10/44] cpuidle,armada: Push RCU-idle into driver

[Peter Zijlstra]

Doing RCU-idle outside the driver, only to then temporarily enable it
again before going idle is daft.

Signed-off-by: Peter Zijlstra (Intel) 
---
 drivers/cpuidle/cpuidle-mvebu-v7.c |7 +++
 1 file changed, 7 insertions(+)

--- a/drivers/cpuidle/cpuidle-mvebu-v7.c
+++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
@@ -36,7 +36,10 @@ static int mvebu_v7_enter_idle(struct cp
if (drv->states[index].flags & MVEBU_V7_FLAG_DEEP_IDLE)
deepidle = true;
 
+   ct_idle_enter();
ret = mvebu_v7_cpu_suspend(deepidle);
+   ct_idle_exit();
+
cpu_pm_exit();
 
if (ret)
@@ -49,6 +52,7 @@ static struct cpuidle_driver armadaxp_id
.name   = "armada_xp_idle",
.states[0]  = ARM_CPUIDLE_WFI_STATE,
.states[1]  = {
+   .flags  = CPUIDLE_FLAG_RCU_IDLE,
.enter  = mvebu_v7_enter_idle,
.exit_latency   = 100,
.power_usage= 50,
@@ -57,6 +61,7 @@ static struct cpuidle_driver armadaxp_id
.desc   = "CPU power down",
},
.states[2]  = {
+   .flags  = CPUIDLE_FLAG_RCU_IDLE,
.enter  = mvebu_v7_enter_idle,
.exit_latency   = 1000,
.power_usage= 5,
@@ -72,6 +77,7 @@ static struct cpuidle_driver armada370_i
.name   = "armada_370_idle",
.states[0]  = ARM_CPUIDLE_WFI_STATE,
.states[1]  = {
+   .flags  = CPUIDLE_FLAG_RCU_IDLE,
.enter  = mvebu_v7_enter_idle,
.exit_latency   = 100,
.power_usage= 5,
@@ -87,6 +93,7 @@ static struct cpuidle_driver armada38x_i
.name   = "armada_38x_idle",
.states[0]  = ARM_CPUIDLE_WFI_STATE,
.states[1]  = {
+   .flags  = CPUIDLE_FLAG_RCU_IDLE,
.enter  = mvebu_v7_enter_idle,
.exit_latency   = 10,
.power_usage= 5,