linux-kernel - Re: [PATCH v8 4/8] PM / EM: add support for other devices than CPUs in Energy Model

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Message-ID: <d45e5592-8e11-858b-d3a3-2ec9ce1d1f54@linaro.org>
Date:   Mon, 1 Jun 2020 23:44:27 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Lukasz Luba <lukasz.luba@....com>, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org, linux-omap@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        linux-imx@....com
Cc:     Dietmar.Eggemann@....com, cw00.choi@...sung.com,
        b.zolnierkie@...sung.com, rjw@...ysocki.net, sudeep.holla@....com,
        viresh.kumar@...aro.org, nm@...com, sboyd@...nel.org,
        rui.zhang@...el.com, amit.kucheria@...durent.com, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, rostedt@...dmis.org,
        qperret@...gle.com, bsegall@...gle.com, mgorman@...e.de,
        shawnguo@...nel.org, s.hauer@...gutronix.de, festevam@...il.com,
        kernel@...gutronix.de, khilman@...nel.org, agross@...nel.org,
        bjorn.andersson@...aro.org, robh@...nel.org,
        matthias.bgg@...il.com, steven.price@....com,
        tomeu.vizoso@...labora.com, alyssa.rosenzweig@...labora.com,
        airlied@...ux.ie, daniel@...ll.ch, liviu.dudau@....com,
        lorenzo.pieralisi@....com, patrick.bellasi@...bug.net,
        orjan.eide@....com, rdunlap@...radead.org, mka@...omium.org
Subject: Re: [PATCH v8 4/8] PM / EM: add support for other devices than CPUs
 in Energy Model

On 27/05/2020 11:58, Lukasz Luba wrote:
> Add support for other devices than CPUs. The registration function
> does not require a valid cpumask pointer and is ready to handle new
> devices. Some of the internal structures has been reorganized in order to
> keep consistent view (like removing per_cpu pd pointers).
> 
> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
> ---

[ ... ]

>  }
>  EXPORT_SYMBOL_GPL(em_register_perf_domain);
> +
> +/**
> + * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
> + * @dev		: Device for which the EM is registered
> + *
> + * Try to unregister the EM for the specified device (but not a CPU).
> + */
> +void em_dev_unregister_perf_domain(struct device *dev)
> +{
> +	if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
> +		return;
> +
> +	if (_is_cpu_device(dev))
> +		return;
> +
> +	mutex_lock(&em_pd_mutex);

Is the mutex really needed?

If this function is called that means there is no more user of the
em_pd, no?

> +	em_debug_remove_pd(dev);
> +
> +	kfree(dev->em_pd->table);
> +	kfree(dev->em_pd);
> +	dev->em_pd = NULL;
> +	mutex_unlock(&em_pd_mutex);
> +}
> +EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
> 


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