linux-kernel - Re: [PATCH v2 3/4] PM / devfreq: Cache OPP table reference in devfreq

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Date:   Tue, 16 Jul 2019 12:12:20 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Sibi Sankar <sibis@...eaurora.org>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Android Kernel Team <kernel-team@...roid.com>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, adharmap@...eaurora.org
Subject: Re: [PATCH v2 3/4] PM / devfreq: Cache OPP table reference in devfreq

On Tue, Jul 16, 2019 at 10:36 AM Sibi Sankar <sibis@...eaurora.org> wrote:
>
> Hey Saravana,
>
> On 6/26/19 3:03 AM, Saravana Kannan wrote:
> > 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@...gle.com>
> > ---
> >   drivers/devfreq/devfreq.c | 6 ++++++
> >   include/linux/devfreq.h   | 1 +
> >   2 files changed, 7 insertions(+)
> >
> > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> > index 6b6991f0e873..ac62b78dc035 100644
> > --- a/drivers/devfreq/devfreq.c
> > +++ b/drivers/devfreq/devfreq.c
> > @@ -597,6 +597,8 @@ 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);
> >   }
> > @@ -677,6 +679,10 @@ struct devfreq *devfreq_add_device(struct device *dev,
> >       devfreq->max_freq = devfreq->scaling_max_freq;
> >
> >       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, "devfreq%d",
> > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> > index fbffa74bfc1b..0d877c9513d7 100644
> > --- a/include/linux/devfreq.h
> > +++ b/include/linux/devfreq.h
> > @@ -156,6 +156,7 @@ struct devfreq {
> >       struct devfreq_dev_profile *profile;
> >       const struct devfreq_governor *governor;
> >       char governor_name[DEVFREQ_NAME_LEN];
> > +     struct opp_table *opp_table;
>
> please add it to the function docs as well

Will do.

-Saravana