linux-kernel - Re: [PATCH 04/11] PM / devfreq: bail out early if no freq changes in devfreq_set

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Message-ID: <CAA+hA=RbvKSyeLVdJBiqnKwGVJQBzKLJi1z68BHoKHeypjQKCQ@mail.gmail.com>
Date:   Wed, 10 Mar 2021 10:42:23 +0800
From:   Dong Aisheng <dongas86@...il.com>
To:     Chanwoo Choi <cwchoi00@...il.com>
Cc:     Dong Aisheng <aisheng.dong@....com>,
        Linux PM <linux-pm@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        dl-linux-imx <linux-imx@....com>,
        open list <linux-kernel@...r.kernel.org>,
        myungjoo.ham@...sung.com, kyungmin.park@...sung.com,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Abel Vesa <abel.vesa@....com>
Subject: Re: [PATCH 04/11] PM / devfreq: bail out early if no freq changes in devfreq_set_target

On Tue, Mar 9, 2021 at 11:47 PM Chanwoo Choi <cwchoi00@...il.com> wrote:
>
> On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
> > It's unnecessary to set the same freq again and run notifier calls.
> >
> > Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> > ---
> >   drivers/devfreq/devfreq.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> > index bf3047896e41..6e80bf70e7b3 100644
> > --- a/drivers/devfreq/devfreq.c
> > +++ b/drivers/devfreq/devfreq.c
> > @@ -358,6 +358,9 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
> >       else
> >               cur_freq = devfreq->previous_freq;
> >
> > +     if (new_freq == cur_freq)
> > +             return 0;
> > +
> >       freqs.old = cur_freq;
> >       freqs.new = new_freq;
> >       devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
> > @@ -374,7 +377,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
> >        * and DEVFREQ_POSTCHANGE because for showing the correct frequency
> >        * change order of between devfreq device and passive devfreq device.
> >        */
> > -     if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
> > +     if (trace_devfreq_frequency_enabled())
> >               trace_devfreq_frequency(devfreq, new_freq, cur_freq);
> >
> >       freqs.new = new_freq;
> >
>
> I'd like you to squash patch4 with patch6 because actually patch6
> is too minor clean-up. I think it is possible.

Got it, will squash when re-send.

Regards
Aisheng

>
> --
> Best Regards,
> Samsung Electronics
> Chanwoo Choi