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SubjectRe: [PATCH V3 1/5] idle/cpuidle: Split cpuidle_idle_call main function into smaller functions
On 02/25/2014 01:38 PM, Daniel Lezcano wrote:
> In order to allow better integration between the cpuidle framework and the
> scheduler, reducing the distance between these two sub-components will
> facilitate this integration by moving part of the cpuidle code in the idle
> task file and, because idle.c is in the sched directory, we have access to
> the scheduler's private structures.
>
> This patch splits the cpuidle_idle_call main entry function into 3 calls
> to a newly added API:
> 1. select the idle state
> 2. enter the idle state
> 3. reflect the idle state
>
> The cpuidle_idle_call calls these three functions to implement the main
> idle entry function.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Acked-by: Nicolas Pitre <nico@linaro.org>
> ---
>
> ChangeLog:
>
> V3:
> * moved broadcast timer outside of cpuidle_enter() as suggested by
> Preeti U Murthy.
> https://lkml.org/lkml/2014/2/24/601
> V2:
> * splitted cpuidle_select error check into 'cpuidle_enabled' function
>
> ---
> drivers/cpuidle/cpuidle.c | 97 ++++++++++++++++++++++++++++++++++++----------
> include/linux/cpuidle.h | 19 +++++++++
> 2 files changed, 95 insertions(+), 21 deletions(-)
>
> Index: cpuidle-next/drivers/cpuidle/cpuidle.c
> ===================================================================
> --- cpuidle-next.orig/drivers/cpuidle/cpuidle.c
> +++ cpuidle-next/drivers/cpuidle/cpuidle.c
> @@ -65,6 +65,26 @@ int cpuidle_play_dead(void)
> }
>
> /**
> + * cpuidle_enabled - check if the cpuidle framework is ready
> + * @dev: cpuidle device for this cpu
> + * @drv: cpuidle driver for this cpu
> + *
> + * Return 0 on success, otherwise:
> + * -NODEV : the cpuidle framework is not available
> + * -EBUSY : the cpuidle framework is not initialized
> + */
> +int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
> +{
> + if (off || !initialized)
> + return -ENODEV;
> +
> + if (!drv || !dev || !dev->enabled)
> + return -EBUSY;
> +
> + return 0;
> +}
> +
> +/**
> * cpuidle_enter_state - enter the state and update stats
> * @dev: cpuidle device for this cpu
> * @drv: cpuidle driver for this cpu
> @@ -108,6 +128,51 @@ int cpuidle_enter_state(struct cpuidle_d
> }
>
> /**
> + * cpuidle_select - ask the cpuidle framework to choose an idle state
> + *
> + * @drv: the cpuidle driver
> + * @dev: the cpuidle device
> + *
> + * Returns the index of the idle state.
> + */
> +int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
> +{
> + return cpuidle_curr_governor->select(drv, dev);
> +}
> +
> +/**
> + * cpuidle_enter - enter into the specified idle state
> + *
> + * @drv: the cpuidle driver tied with the cpu
> + * @dev: the cpuidle device
> + * @index: the index in the idle state table
> + *
> + * Returns the index in the idle state, < 0 in case of error.
> + * The error code depends on the backend driver
> + */
> +int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
> + int index)
> +{
> + if (cpuidle_state_is_coupled(dev, drv, index))
> + return cpuidle_enter_state_coupled(dev, drv, index);
> + return cpuidle_enter_state(dev, drv, index);
> +}
> +
> +/**
<snip>
>
> - if (cpuidle_state_is_coupled(dev, drv, next_state))
> - entered_state = cpuidle_enter_state_coupled(dev, drv,
> - next_state);
> - else
> - entered_state = cpuidle_enter_state(dev, drv, next_state);
> + entered_state = cpuidle_enter(drv, dev, next_state);

Wouldn't you need to check for return value on cpuidle_enter()?

Regards
Preeti U Murthy



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