Re: [PATCH v6 2/3] PM / devfreq: Cache OPP table reference in devfreq

From: Chanwoo Choi
Date: Thu Feb 04 2021 - 03:32:07 EST


Hi Hsin-Yi,

On 2/4/21 5:14 PM, Hsin-Yi Wang wrote:
> From: Saravana Kannan <saravanak@xxxxxxxxxx>
>
> The OPP table can be used often in devfreq. Trying to get it each time can
> be expensive, so cache it in the devfreq struct.
>
> Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
> Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> Acked-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> ---
> drivers/devfreq/devfreq.c | 6 ++++++
> include/linux/devfreq.h | 2 ++
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 6aa10de792b33..a5899c9ae16fc 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -757,6 +757,8 @@ static void devfreq_dev_release(struct device *dev)
> if (devfreq->profile->exit)
> devfreq->profile->exit(devfreq->dev.parent);
>
> + if (devfreq->opp_table)
> + dev_pm_opp_put_opp_table(devfreq->opp_table);
> mutex_destroy(&devfreq->lock);
> kfree(devfreq);
> }
> @@ -844,6 +846,10 @@ struct devfreq *devfreq_add_device(struct device *dev,
> }
>
> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
> + devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
> + if (IS_ERR(devfreq->opp_table))
> + devfreq->opp_table = NULL;
> +
> atomic_set(&devfreq->suspend_count, 0);
>
> dev_set_name(&devfreq->dev, "%s", dev_name(dev));
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index b6d3bae1c74d8..26ea0850be9bb 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -137,6 +137,7 @@ struct devfreq_stats {
> * using devfreq.
> * @profile: device-specific devfreq profile
> * @governor: method how to choose frequency based on the usage.
> + * @opp_table: Reference to OPP table of dev.parent, if one exists.
> * @nb: notifier block used to notify devfreq object that it should
> * reevaluate operable frequencies. Devfreq users may use
> * devfreq.nb to the corresponding register notifier call chain.
> @@ -173,6 +174,7 @@ struct devfreq {
> struct device dev;
> struct devfreq_dev_profile *profile;
> const struct devfreq_governor *governor;
> + struct opp_table *opp_table;
> struct notifier_block nb;
> struct delayed_work work;
>
>

Acked-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>

--
Best Regards,
Chanwoo Choi
Samsung Electronics