diff mbox series

[1/2] cpuidle: Don't pass any values to cpuidle_not_available

Message ID 20230711-cpuidle-v1-1-f391224b3140@gmail.com
State New
Headers
Series s2idle fixes for systems without cpuidle |

Commit Message

Kazuki Hashimoto July 11, 2023, 5:54 a.m. UTC 
  There's no reason to pass any values to cpuidle_not_available() as the
function works standalone. Since we're planning to use the function in
other places, make it so to avoid code duplication.

Signed-off-by: Kazuki Hashimoto <kazukih0205@gmail.com>
---
 drivers/cpuidle/cpuidle.c | 6 ++++--
 include/linux/cpuidle.h   | 6 ++----
 kernel/sched/idle.c       | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

Comments

Peter Zijlstra July 11, 2023, 7:42 a.m. UTC | #1 
On Tue, Jul 11, 2023 at 02:54:21PM +0900, Kazuki Hashimoto wrote:
> There's no reason to pass any values to cpuidle_not_available() as the
> function works standalone. Since we're planning to use the function in
> other places, make it so to avoid code duplication.
> 
> Signed-off-by: Kazuki Hashimoto <kazukih0205@gmail.com>
> ---
>  drivers/cpuidle/cpuidle.c | 6 ++++--
>  include/linux/cpuidle.h   | 6 ++----
>  kernel/sched/idle.c       | 2 +-
>  3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 737a026ef58a..c9ba51e0fa38 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -49,9 +49,11 @@ void disable_cpuidle(void)
>  	off = 1;
>  }
>  
> -bool cpuidle_not_available(struct cpuidle_driver *drv,
> -			   struct cpuidle_device *dev)
> +bool cpuidle_not_available(void)
>  {
> +	struct cpuidle_device *dev = cpuidle_get_device();
> +	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> +
>  	return off || !initialized || !drv || !dev || !dev->enabled;
>  }

It appears to me these are a lot of conditions to check *every* time we
go idle -- especially since they hardly, if ever, change.

Can't cpuidle track all this in a single global variable, preferably as
a static_key ?
Kazuki Hashimoto July 11, 2023, 6:48 p.m. UTC | #2 
on oue, Jul 11, 2023 at 09:42:31AM +0200, Peter Zijlstra wrote:
> On Tue, Jul 11, 2023 at 02:54:21PM +0900, Kazuki Hashimoto wrote:
> > There's no reason to pass any values to cpuidle_not_available() as the
> > function works standalone. Since we're planning to use the function in
> > other places, make it so to avoid code duplication.
> > 
> > Signed-off-by: Kazuki Hashimoto <kazukih0205@gmail.com>
> > ---
> >  drivers/cpuidle/cpuidle.c | 6 ++++--
> >  include/linux/cpuidle.h   | 6 ++----
> >  kernel/sched/idle.c       | 2 +-
> >  3 files changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> > index 737a026ef58a..c9ba51e0fa38 100644
> > --- a/drivers/cpuidle/cpuidle.c
> > +++ b/drivers/cpuidle/cpuidle.c
> > @@ -49,9 +49,11 @@ void disable_cpuidle(void)
> >  	off = 1;
> >  }
> >  
> > -bool cpuidle_not_available(struct cpuidle_driver *drv,
> > -			   struct cpuidle_device *dev)
> > +bool cpuidle_not_available(void)
> >  {
> > +	struct cpuidle_device *dev = cpuidle_get_device();
> > +	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> > +
> >  	return off || !initialized || !drv || !dev || !dev->enabled;
> >  }
> 
> It appears to me these are a lot of conditions to check *every* time we
> go idle -- especially since they hardly, if ever, change.
> 
> Can't cpuidle track all this in a single global variable, preferably as
> a static_key ?
I don't think so? I'll drop this one though since it adds unnecesary
overhead.

Thanks,
Kazuki
diff mbox series

Patch

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 737a026ef58a..c9ba51e0fa38 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -49,9 +49,11 @@  void disable_cpuidle(void)
 	off = 1;
 }
 
-bool cpuidle_not_available(struct cpuidle_driver *drv,
-			   struct cpuidle_device *dev)
+bool cpuidle_not_available(void)
 {
+	struct cpuidle_device *dev = cpuidle_get_device();
+	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
 	return off || !initialized || !drv || !dev || !dev->enabled;
 }
 
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 3183aeb7f5b4..a0ce9b6d16ce 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -169,8 +169,7 @@  struct cpuidle_driver {
 
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
-extern bool cpuidle_not_available(struct cpuidle_driver *drv,
-				  struct cpuidle_device *dev);
+extern bool cpuidle_not_available(void);
 
 extern int cpuidle_select(struct cpuidle_driver *drv,
 			  struct cpuidle_device *dev,
@@ -204,8 +203,7 @@  static inline struct cpuidle_device *cpuidle_get_device(void)
 {return __this_cpu_read(cpuidle_devices); }
 #else
 static inline void disable_cpuidle(void) { }
-static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
-					 struct cpuidle_device *dev)
+static inline bool cpuidle_not_available(void)
 {return true; }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
 				 struct cpuidle_device *dev, bool *stop_tick)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 342f58a329f5..865674d2e420 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -164,7 +164,7 @@  static void cpuidle_idle_call(void)
 	 * step to the grace period
 	 */
 
-	if (cpuidle_not_available(drv, dev)) {
+	if (cpuidle_not_available()) {
 		tick_nohz_idle_stop_tick();
 
 		default_idle_call();