Re: [PATCH 7/7] devfreq: move statistics to separate struct

[Lukasz Luba <lukasz.luba@arm.com>]

Hi Chanwoo,

On 12/17/19 12:07 AM, Chanwoo Choi wrote:
> Hi Lukaz,
> 
> On 12/16/19 10:01 PM, Lukasz Luba wrote:
>> Hi Bartek,
>>
>> [added Dietmar, Robin, Andrzej (for upcoming DRM drm-misc-next)]
>>
>> On 11/15/19 12:40 PM, Bartlomiej Zolnierkiewicz wrote:
>>>
>>> [ added Zhang, Eduardo, Ørjan and Javi to Cc: ]
>>>
>>> On 11/15/19 7:21 AM, Chanwoo Choi wrote:
>>>> Hi Bartlomiej,
>>>>
>>>> On 11/15/19 12:25 PM, Chanwoo Choi wrote:
>>>>> Hi Bartlomiej,
>>>>>
>>>>> On 11/15/19 3:01 AM, Bartlomiej Zolnierkiewicz wrote:
>>>>>>
>>>>>> Hi Chanwoo,
>>>>>>
>>>>>> On 11/14/19 2:52 AM, Chanwoo Choi wrote:
>>>>>>> Hi Kamil,
>>>>>>>
>>>>>>> The 'freq_table' and 'max_state' in the devfreq_dev_profile
>>>>>>> were used in the ARM Mali device driver[1][2][3]. Although ARM Mali
>>>>>>> device driver was posted to mainline kernel, they used
>>>>>>> them for a long time. It means that this patch break
>>>>>>> the compatibility. The ARM Mali drivers are very
>>>>>>> important devfreq device driver.
>>>>>>
>>>>>> This argument is not a a technical one and the official upstream
>>>>>> kernel policy is to not depend on out-of-tree drivers.
>>>>>>
>>>>>> Besides the ARM Mali drivers are full of code like:
>>>>>>
>>>>>> #if LINUX_VERSION_CODE >= KERNEL_VERSION(x, y, z)
>>>>>> ...
>>>>>> #else
>>>>>> ...
>>>>>> #endif
>>>>>>
>>>>>> so few more instances of similar code won't do any harm.. ;-)
>>>>>>
>>>>>>> [1] https://protect2.fireeye.com/url?k=909caa5c-cd52abe8-909d2113-000babdfecba-812f16576c3614a3&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/bifrost-kernel#
>>>>>>> [2] https://protect2.fireeye.com/url?k=33265f96-6ee85e22-3327d4d9-000babdfecba-44c2daec328712e6&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/midgard-kernel
>>>>>>> [3] https://protect2.fireeye.com/url?k=69bdcab0-3473cb04-69bc41ff-000babdfecba-4b576facf85e0208&u=https://developer.arm.com/tools-and-software/graphics-and-gaming/mali-drivers/utgard-kernel
>>>>>>
>>>>>> I took a look at ARM Mali drivers source code anyway and I fail to
>>>>>> see a rationale behind their behavior of doing 'freq_table' and
>>>>>> 'max_state' initialization in the driver itself (instead of leaving
>>>>>> it up to the devfreq core code, like all in-kernel drivers are doing
>>>>>> already).
>>>>>>
>>>>>> Could you please explain rationale behind ARM Mali drivers' special
>>>>>> needs?
>>>>>>
>>>>>> [ Both ARM Mali and devfreq core code are using generic PM OPP code
>>>>>>     these days to do 'freq_table' and 'max_state' initialization, the
>>>>>>     only difference seems to be that ARM Mali creates the frequency
>>>>>>     table in the descending order (but there also seems to be no real
>>>>>>     need for it). ]
>>>>>>
>>>>>> Maybe this is an opportunity to simplify also the ARM Mali driver?
>>>>>
>>>>> OK. I agree to simplify them on this time.
>>>>> For touching the 'freq_table' and 'max_state', need to fix
>>>>> the descending order of freq_table.
>>>>>
>>>>> The partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>> requires the descending order of freq_table. Have to change it by using
>>>>> the ascending time or support both ascending and descending order for freq_table.
>>>>>
>>>>> 1. Move freq_table, max_state of devfreq_dev_profile to struct devfreq
>>>>> 2. Edit partition_enable_ops() in the drivers/thermal/devfreq_cooling.c
>>>>>      by using ascending order instead of descending order.
>>>>>
>>>>
>>>> After changed about 'freq_table' and 'max_state', the build error
>>>> will happen on ARM mail driver because the initialization code of
>>>> 'freq_table' in ARM mali driver, didn't check the kernel version.
>>>>
>>>> The first devfreq patch provided the 'freq_table' as optional variable
>>>> in the 'struct devfreq_dev_profile'. Even if ARM mali driver is out of mainline tree,
>>>> this change seems that break the usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> So, if there are no any beneficial reason, I just keep the current status of 'freq_table'
>>>> in order to keep the previous usage rule of 'freq_table' in 'struct devfreq_dev_profile'.
>>>>
>>>> Frankly, I'm note sure that it is necessary. I don't want to make
>>>> the side-effect without any useful reason.
>>>>
>>>> But,
>>>> Separately, have to fix the ordering issue of partition_enable_ops()
>>>> in the drivers/thermal/devfreq_cooling.c.
>>>
>>> Hmmm.. fixing partition_enable_opps() should be trivial but I wonder
>>> why we are carrying devfreq_cooling.c code in upstream kernel at all?
>>
>> Well, the devfreq_cooling.c is going to have a client in mainline:
>> the GPU driver - Panfrost.
>>
>> It is already in DRM branch 'drm-misc-next':
>> https://protect2.fireeye.com/url?k=75a0e087-283b1ce4-75a16bc8-0cc47a31cdbc-4953aa9e0574f6dc&u=https://patchwork.freedesktop.org/patch/342848/
>>
>> Regarding the devfreq_cooling.c code structure.
>> I am currently working on cleaning up the devfreq cooling code and
>> adding Energy Model instead for private freq, power tables. It will be
>> in similar fashion as it is done in cpufreq_cooling. The model will
>> be also simplified so hopefully more clients would come.
>> It is under internal review and will be posted shortly.
> 
> Good news about Energy Model. When you send the patch related to Energy model,
> please add me to Cc list.

I will add you, thanks. More eyeballs in capturing bugs are more than
welcome.

Regards,
Lukasz

> 
>>
>>>
>>> It has been merged in the following commit:
>>>
>>> commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
>>> Author: Ørjan Eide <orjan.eide@arm.com>
>>> Date:   Thu Sep 10 18:09:30 2015 +0100
>>>
>>>       thermal: Add devfreq cooling
>>>            Add a generic thermal cooling device for devfreq, that is similar to
>>>       cpu_cooling.
>>>            The device must use devfreq.  In order to use the power extension of the
>>>       cooling device, it must have registered its OPPs using the OPP library.
>>>            Cc: Zhang Rui <rui.zhang@intel.com>
>>>       Cc: Eduardo Valentin <edubezval@gmail.com>
>>>       Signed-off-by: Javi Merino <javi.merino@arm.com>
>>>       Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
>>>       Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
>>> ...
>>>
>>> but 4 years later there is still no single in-kernel user for this code?
>>
>> There will be, via DRM tree.
>>
>> Regards,
>> Lukasz
>>
>>>
>>> Best regards,
>>> -- 
>>> Bartlomiej Zolnierkiewicz
>>> Samsung R&D Institute Poland
>>> Samsung Electronics
>>>
>>>>>>
>>>>>>> Also, the devfreq device driver specifies their own
>>>>>>> information and data into devfreq_dev_profile structure
>>>>>>> before registering the devfreq device with devfreq_add_device().
>>>>>>> This patch breaks the basic usage rule of devfreq_dev_profile structure.
>>>>>>
>>>>>> Well, 'struct devfreq_stats *stats' can be trivially moved out of
>>>>>> 'struct devfreq_profile' to 'struct devfreq' if you prefer it that
>>>>>> way..
>>>>>>
>>>>>> Best regards,
>>>>>> -- 
>>>>>> Bartlomiej Zolnierkiewicz
>>>>>> Samsung R&D Institute Poland
>>>>>> Samsung Electronics
>>>>>>
>>>>>>> So, I can't agree this patch. Not ack.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Chanwoo Choi
>>>>>>>
>>>>>>> On 11/13/19 6:13 PM, Kamil Konieczny wrote:
>>>>>>>> Count time and transitions between devfreq frequencies in separate struct
>>>>>>>> for improved code readability and maintenance.
>>>>>>>>
>>>>>>>> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
>>>>>>>> ---
>>>>>>>>    drivers/devfreq/devfreq.c          | 156 ++++++++++++++++-------------
>>>>>>>>    drivers/devfreq/exynos-bus.c       |   6 +-
>>>>>>>>    drivers/devfreq/governor_passive.c |  26 +++--
>>>>>>>>    include/linux/devfreq.h            |  43 ++++----
>>>>>>>>    4 files changed, 129 insertions(+), 102 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>>>>>> index d79412b0de59..d85867a91230 100644
>>>>>>>> --- a/drivers/devfreq/devfreq.c
>>>>>>>> +++ b/drivers/devfreq/devfreq.c
>>>>>>>> @@ -105,10 +105,11 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        int lev;
>>>>>>>>    -    for (lev = 0; lev < devfreq->profile->max_state; lev++)
>>>>>>>> -        if (freq == devfreq->profile->freq_table[lev])
>>>>>>>> +    for (lev = 0; lev < stats->max_state; lev++)
>>>>>>>> +        if (freq == stats->freq_table[lev])
>>>>>>>>                return lev;
>>>>>>>>          return -EINVAL;
>>>>>>>> @@ -117,56 +118,64 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>    {
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        unsigned long freq;
>>>>>>>> -    int i, count;
>>>>>>>> +    int i, count, err = -ENOMEM;
>>>>>>>>          /* Initialize the freq_table from OPP table */
>>>>>>>>        count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
>>>>>>>>        if (count <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    -    profile->max_state = count;
>>>>>>>> -    profile->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> -                    count,
>>>>>>>> -                    sizeof(*profile->freq_table),
>>>>>>>> -                    GFP_KERNEL);
>>>>>>>> -    if (!profile->freq_table) {
>>>>>>>> -        profile->max_state = 0;
>>>>>>>> +    stats = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                 sizeof(struct devfreq_stats), GFP_KERNEL);
>>>>>>>> +    if (!stats)
>>>>>>>>            return -ENOMEM;
>>>>>>>> -    }
>>>>>>>>    -    for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
>>>>>>>> +    profile->stats = stats;
>>>>>>>> +    stats->max_state = count;
>>>>>>>> +    stats->freq_table = devm_kcalloc(devfreq->dev.parent,
>>>>>>>> +                     count,
>>>>>>>> +                     sizeof(*stats->freq_table),
>>>>>>>> +                     GFP_KERNEL);
>>>>>>>> +    if (!stats->freq_table)
>>>>>>>> +        goto err_no_mem;
>>>>>>>> +
>>>>>>>> +    for (i = 0, freq = 0; i < count; i++, freq++) {
>>>>>>>>            opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
>>>>>>>>            if (IS_ERR(opp)) {
>>>>>>>> -            devm_kfree(devfreq->dev.parent, profile->freq_table);
>>>>>>>> -            profile->max_state = 0;
>>>>>>>> -            return PTR_ERR(opp);
>>>>>>>> +            devm_kfree(devfreq->dev.parent, stats->freq_table);
>>>>>>>> +            stats->max_state = 0;
>>>>>>>> +            err = PTR_ERR(opp);
>>>>>>>> +            goto err_no_mem;
>>>>>>>>            }
>>>>>>>>            dev_pm_opp_put(opp);
>>>>>>>> -        profile->freq_table[i] = freq;
>>>>>>>> +        stats->freq_table[i] = freq;
>>>>>>>>        }
>>>>>>>>    -    profile->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> -                        array3_size(sizeof(unsigned int),
>>>>>>>> -                            count, count),
>>>>>>>> -                        GFP_KERNEL);
>>>>>>>> -    if (!profile->trans_table)
>>>>>>>> +    stats->trans_table = devm_kzalloc(devfreq->dev.parent,
>>>>>>>> +                      array3_size(sizeof(unsigned int),
>>>>>>>> +                              count, count),
>>>>>>>> +                      GFP_KERNEL);
>>>>>>>> +    if (!stats->trans_table)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> -                          sizeof(*profile->time_in_state),
>>>>>>>> -                          GFP_KERNEL);
>>>>>>>> -    if (!profile->time_in_state)
>>>>>>>> +    stats->time_in_state = devm_kcalloc(devfreq->dev.parent, count,
>>>>>>>> +                        sizeof(*stats->time_in_state),
>>>>>>>> +                        GFP_KERNEL);
>>>>>>>> +    if (!stats->time_in_state)
>>>>>>>>            goto err_no_mem;
>>>>>>>>    -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_lock_init(&profile->stats_lock);
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_lock_init(&stats->stats_lock);
>>>>>>>>          return 0;
>>>>>>>>    err_no_mem:
>>>>>>>> -    profile->max_state = 0;
>>>>>>>> -    return -ENOMEM;
>>>>>>>> +    stats->max_state = 0;
>>>>>>>> +    devm_kfree(devfreq->dev.parent, profile->stats);
>>>>>>>> +    profile->stats = NULL;
>>>>>>>> +    return err;
>>>>>>>>    }
>>>>>>>>      /**
>>>>>>>> @@ -176,7 +185,7 @@ static int set_freq_table(struct devfreq *devfreq)
>>>>>>>>     */
>>>>>>>>    int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>    {
>>>>>>>> -    struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = devfreq->profile->stats;
>>>>>>>>        unsigned long long cur_time;
>>>>>>>>        int lev, prev_lev, ret = 0;
>>>>>>>>    @@ -184,22 +193,21 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>          /* Immediately exit if previous_freq is not initialized yet. */
>>>>>>>>        if (!devfreq->previous_freq) {
>>>>>>>> -        spin_lock(&profile->stats_lock);
>>>>>>>> -        profile->last_time = cur_time;
>>>>>>>> -        spin_unlock(&profile->stats_lock);
>>>>>>>> +        spin_lock(&stats->stats_lock);
>>>>>>>> +        stats->last_time = cur_time;
>>>>>>>> +        spin_unlock(&stats->stats_lock);
>>>>>>>>            return 0;
>>>>>>>>        }
>>>>>>>>          prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        if (prev_lev < 0) {
>>>>>>>>            ret = prev_lev;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>    -    profile->time_in_state[prev_lev] +=
>>>>>>>> -             cur_time - profile->last_time;
>>>>>>>> +    stats->time_in_state[prev_lev] += cur_time - stats->last_time;
>>>>>>>>        lev = devfreq_get_freq_level(devfreq, freq);
>>>>>>>>        if (lev < 0) {
>>>>>>>>            ret = lev;
>>>>>>>> @@ -207,14 +215,14 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        }
>>>>>>>>          if (lev != prev_lev) {
>>>>>>>> -        profile->trans_table[(prev_lev *
>>>>>>>> -                profile->max_state) + lev]++;
>>>>>>>> -        profile->total_trans++;
>>>>>>>> +        stats->trans_table[(prev_lev *
>>>>>>>> +                stats->max_state) + lev]++;
>>>>>>>> +        stats->total_trans++;
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    profile->last_time = cur_time;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    stats->last_time = cur_time;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return ret;
>>>>>>>>    }
>>>>>>>>    EXPORT_SYMBOL(devfreq_update_status);
>>>>>>>> @@ -504,9 +512,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>>>>>>>>            queue_delayed_work(devfreq_wq, &devfreq->work,
>>>>>>>>                msecs_to_jiffies(profile->polling_ms));
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&profile->stats->stats_lock);
>>>>>>>> +    profile->stats->last_time = get_jiffies_64();
>>>>>>>> +    spin_unlock(&profile->stats->stats_lock);
>>>>>>>>        devfreq->stop_polling = false;
>>>>>>>>          if (profile->get_cur_freq &&
>>>>>>>> @@ -677,7 +685,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>>>>>>>        devfreq->data = data;
>>>>>>>>        devfreq->nb.notifier_call = devfreq_notifier_call;
>>>>>>>>    -    if (!profile->max_state && !profile->freq_table) {
>>>>>>>> +    if (!profile->stats) {
>>>>>>>>            mutex_unlock(&devfreq->lock);
>>>>>>>>            err = set_freq_table(devfreq);
>>>>>>>>            if (err < 0)
>>>>>>>> @@ -1282,6 +1290,7 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1297,13 +1306,13 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get minimum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>>                value = freq_table[0];
>>>>>>>>            else
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>        }
>>>>>>>>          df->min_freq = value;
>>>>>>>> @@ -1326,6 +1335,7 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                      const char *buf, size_t count)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(dev);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        unsigned long value;
>>>>>>>>        int ret;
>>>>>>>>    @@ -1341,11 +1351,11 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
>>>>>>>>                goto unlock;
>>>>>>>>            }
>>>>>>>>        } else {
>>>>>>>> -        unsigned long *freq_table = df->profile->freq_table;
>>>>>>>> +        unsigned long *freq_table = stats->freq_table;
>>>>>>>>              /* Get maximum frequency according to sorting order */
>>>>>>>> -        if (freq_table[0] < freq_table[df->profile->max_state - 1])
>>>>>>>> -            value = freq_table[df->profile->max_state - 1];
>>>>>>>> +        if (freq_table[0] < freq_table[stats->max_state - 1])
>>>>>>>> +            value = freq_table[stats->max_state - 1];
>>>>>>>>            else
>>>>>>>>                value = freq_table[0];
>>>>>>>>        }
>>>>>>>> @@ -1373,14 +1383,15 @@ static ssize_t available_frequencies_show(struct device *d,
>>>>>>>>                          char *buf)
>>>>>>>>    {
>>>>>>>>        struct devfreq *df = to_devfreq(d);
>>>>>>>> +    struct devfreq_stats *stats = df->profile->stats;
>>>>>>>>        ssize_t count = 0;
>>>>>>>>        int i;
>>>>>>>>          mutex_lock(&df->lock);
>>>>>>>>    -    for (i = 0; i < df->profile->max_state; i++)
>>>>>>>> +    for (i = 0; i < stats->max_state; i++)
>>>>>>>>            count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
>>>>>>>> -                "%lu ", df->profile->freq_table[i]);
>>>>>>>> +                "%lu ", stats->freq_table[i]);
>>>>>>>>          mutex_unlock(&df->lock);
>>>>>>>>        /* Truncate the trailing space */
>>>>>>>> @@ -1398,9 +1409,10 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>        struct devfreq_dev_profile *profile = devfreq->profile;
>>>>>>>> +    struct devfreq_stats *stats = profile->stats;
>>>>>>>> +    unsigned int max_state = stats->max_state;
>>>>>>>>        ssize_t len;
>>>>>>>>        int i, j;
>>>>>>>> -    unsigned int max_state = profile->max_state;
>>>>>>>>          if (!devfreq->stop_polling &&
>>>>>>>>                devfreq_update_status(devfreq, devfreq->previous_freq))
>>>>>>>> @@ -1411,45 +1423,45 @@ static ssize_t trans_stat_show(struct device *dev,
>>>>>>>>        len = sprintf(buf, "     From  :   To\n");
>>>>>>>>        len += sprintf(buf + len, "           :");
>>>>>>>>    -    spin_lock(&profile->stats_lock);
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>>        for (i = 0; i < max_state; i++)
>>>>>>>>            len += sprintf(buf + len, "%10lu",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>          len += sprintf(buf + len, "   time(ms)\n");
>>>>>>>>          for (i = 0; i < max_state; i++) {
>>>>>>>> -        if (profile->freq_table[i] == devfreq->previous_freq)
>>>>>>>> +        if (stats->freq_table[i] == devfreq->previous_freq)
>>>>>>>>                len += sprintf(buf + len, "*");
>>>>>>>>            else
>>>>>>>>                len += sprintf(buf + len, " ");
>>>>>>>>              len += sprintf(buf + len, "%10lu:",
>>>>>>>> -                profile->freq_table[i]);
>>>>>>>> +                stats->freq_table[i]);
>>>>>>>>            for (j = 0; j < max_state; j++)
>>>>>>>>                len += sprintf(buf + len, "%10u",
>>>>>>>> -                profile->trans_table[(i * max_state) + j]);
>>>>>>>> +                stats->trans_table[(i * max_state) + j]);
>>>>>>>>            len += sprintf(buf + len, "%10llu\n", (u64)
>>>>>>>> -            jiffies64_to_msecs(profile->time_in_state[i]));
>>>>>>>> +            jiffies64_to_msecs(stats->time_in_state[i]));
>>>>>>>>        }
>>>>>>>>          len += sprintf(buf + len, "Total transition : %u\n",
>>>>>>>> -                    profile->total_trans);
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +                    stats->total_trans);
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>        return len;
>>>>>>>>    }
>>>>>>>>    static DEVICE_ATTR_RO(trans_stat);
>>>>>>>>    -static void defvreq_stats_clear_table(struct devfreq_dev_profile *profile)
>>>>>>>> +static void defvreq_stats_clear_table(struct devfreq_stats *stats)
>>>>>>>>    {
>>>>>>>> -    unsigned int count = profile->max_state;
>>>>>>>> -
>>>>>>>> -    spin_lock(&profile->stats_lock);
>>>>>>>> -    memset(profile->time_in_state, 0, count * sizeof(u64));
>>>>>>>> -    memset(profile->trans_table, 0, count * count * sizeof(int));
>>>>>>>> -    profile->last_time = get_jiffies_64();
>>>>>>>> -    profile->total_trans = 0;
>>>>>>>> -    spin_unlock(&profile->stats_lock);
>>>>>>>> +    unsigned int count = stats->max_state;
>>>>>>>> +
>>>>>>>> +    spin_lock(&stats->stats_lock);
>>>>>>>> +    memset(stats->time_in_state, 0, count * sizeof(u64));
>>>>>>>> +    memset(stats->trans_table, 0, count * count * sizeof(int));
>>>>>>>> +    stats->last_time = get_jiffies_64();
>>>>>>>> +    stats->total_trans = 0;
>>>>>>>> +    spin_unlock(&stats->stats_lock);
>>>>>>>>    }
>>>>>>>>      static ssize_t trans_reset_store(struct device *dev,
>>>>>>>> @@ -1459,7 +1471,7 @@ static ssize_t trans_reset_store(struct device *dev,
>>>>>>>>    {
>>>>>>>>        struct devfreq *devfreq = to_devfreq(dev);
>>>>>>>>    -    defvreq_stats_clear_table(devfreq->profile);
>>>>>>>> +    defvreq_stats_clear_table(devfreq->profile->stats);
>>>>>>>>          return count;
>>>>>>>>    }
>>>>>>>> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
>>>>>>>> index d9f377912c10..b212aae2bb3e 100644
>>>>>>>> --- a/drivers/devfreq/exynos-bus.c
>>>>>>>> +++ b/drivers/devfreq/exynos-bus.c
>>>>>>>> @@ -496,9 +496,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
>>>>>>>>        }
>>>>>>>>      out:
>>>>>>>> -    max_state = bus->devfreq->profile->max_state;
>>>>>>>> -    min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
>>>>>>>> -    max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
>>>>>>>> +    max_state = profile->stats->max_state;
>>>>>>>> +    min_freq = (profile->stats->freq_table[0] / 1000);
>>>>>>>> +    max_freq = (profile->stats->freq_table[max_state - 1] / 1000);
>>>>>>>>        pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
>>>>>>>>                dev_name(dev), min_freq, max_freq);
>>>>>>>>    diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
>>>>>>>> index 58308948b863..b2d87a88335c 100644
>>>>>>>> --- a/drivers/devfreq/governor_passive.c
>>>>>>>> +++ b/drivers/devfreq/governor_passive.c
>>>>>>>> @@ -18,6 +18,8 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>        struct devfreq_passive_data *p_data
>>>>>>>>                = (struct devfreq_passive_data *)devfreq->data;
>>>>>>>>        struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
>>>>>>>> +    struct devfreq_stats *parent_stats = parent_devfreq->profile->stats;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>        unsigned long child_freq = ULONG_MAX;
>>>>>>>>        struct dev_pm_opp *opp;
>>>>>>>>        int i, count, ret = 0;
>>>>>>>> @@ -47,10 +49,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * device. And then the index is used for getting the suitable
>>>>>>>>         * new frequency for passive devfreq device.
>>>>>>>>         */
>>>>>>>> -    if (!devfreq->profile || !devfreq->profile->freq_table
>>>>>>>> -        || devfreq->profile->max_state <= 0)
>>>>>>>> +    if (!devfreq->profile || !devfreq->profile->stats ||
>>>>>>>> +        devfreq->profile->stats->max_state <= 0 ||
>>>>>>>> +        !parent_devfreq->profile ||    !parent_devfreq->profile->stats ||
>>>>>>>> +        parent_devfreq->profile->stats->max_state <= 0)
>>>>>>>>            return -EINVAL;
>>>>>>>>    +    stats = devfreq->profile->stats;
>>>>>>>> +    parent_stats = parent_devfreq->profile->stats;
>>>>>>>>        /*
>>>>>>>>         * The passive governor have to get the correct frequency from OPP
>>>>>>>>         * list of parent device. Because in this case, *freq is temporary
>>>>>>>> @@ -68,21 +74,21 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
>>>>>>>>         * Get the OPP table's index of decided freqeuncy by governor
>>>>>>>>         * of parent device.
>>>>>>>>         */
>>>>>>>> -    for (i = 0; i < parent_devfreq->profile->max_state; i++)
>>>>>>>> -        if (parent_devfreq->profile->freq_table[i] == *freq)
>>>>>>>> +    for (i = 0; i < parent_stats->max_state; i++)
>>>>>>>> +        if (parent_stats->freq_table[i] == *freq)
>>>>>>>>                break;
>>>>>>>>    -    if (i == parent_devfreq->profile->max_state) {
>>>>>>>> +    if (i == parent_stats->max_state) {
>>>>>>>>            ret = -EINVAL;
>>>>>>>>            goto out;
>>>>>>>>        }
>>>>>>>>          /* Get the suitable frequency by using index of parent device. */
>>>>>>>> -    if (i < devfreq->profile->max_state) {
>>>>>>>> -        child_freq = devfreq->profile->freq_table[i];
>>>>>>>> +    if (i < stats->max_state) {
>>>>>>>> +        child_freq = stats->freq_table[i];
>>>>>>>>        } else {
>>>>>>>> -        count = devfreq->profile->max_state;
>>>>>>>> -        child_freq = devfreq->profile->freq_table[count - 1];
>>>>>>>> +        count = stats->max_state;
>>>>>>>> +        child_freq = stats->freq_table[count - 1];
>>>>>>>>        }
>>>>>>>>          /* Return the suitable frequency for passive device. */
>>>>>>>> @@ -109,7 +115,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
>>>>>>>>        if (ret < 0)
>>>>>>>>            goto out;
>>>>>>>>    -    if (devfreq->profile->freq_table
>>>>>>>> +    if (devfreq->profile->stats
>>>>>>>>            && (devfreq_update_status(devfreq, freq)))
>>>>>>>>            dev_err(&devfreq->dev,
>>>>>>>>                "Couldn't update frequency transition information.\n");
>>>>>>>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>>>>>>>> index 4ceb2a517a9c..8459af1a1583 100644
>>>>>>>> --- a/include/linux/devfreq.h
>>>>>>>> +++ b/include/linux/devfreq.h
>>>>>>>> @@ -64,6 +64,30 @@ struct devfreq_dev_status {
>>>>>>>>     */
>>>>>>>>    #define DEVFREQ_FLAG_LEAST_UPPER_BOUND        0x1
>>>>>>>>    +/**
>>>>>>>> + * struct devfreq_stats - Devfreq's transitions stats counters
>>>>>>>> + * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> + *            and freq_table must be generated in ascending order.
>>>>>>>> + * @max_state:        The size of freq_table.
>>>>>>>> + * @total_trans:    Number of devfreq transitions
>>>>>>>> + * @trans_table:    Statistics of devfreq transitions
>>>>>>>> + * @time_in_state:    Statistics of devfreq states
>>>>>>>> + * @last_time:        The last time stats were updated
>>>>>>>> + * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> + *            last_time and total_trans used for statistics
>>>>>>>> + */
>>>>>>>> +struct devfreq_stats {
>>>>>>>> +    unsigned long *freq_table;
>>>>>>>> +    unsigned int max_state;
>>>>>>>> +
>>>>>>>> +    /* information for device frequency transition */
>>>>>>>> +    unsigned int total_trans;
>>>>>>>> +    unsigned int *trans_table;
>>>>>>>> +    u64 *time_in_state;
>>>>>>>> +    unsigned long long last_time;
>>>>>>>> +    spinlock_t stats_lock;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>>    /**
>>>>>>>>     * struct devfreq_dev_profile - Devfreq's user device profile
>>>>>>>>     * @initial_freq:    The operating frequency when devfreq_add_device() is
>>>>>>>> @@ -88,15 +112,7 @@ struct devfreq_dev_status {
>>>>>>>>     *            from devfreq_remove_device() call. If the user
>>>>>>>>     *            has registered devfreq->nb at a notifier-head,
>>>>>>>>     *            this is the time to unregister it.
>>>>>>>> - * @freq_table:        Optional list of frequencies to support statistics
>>>>>>>> - *            and freq_table must be generated in ascending order.
>>>>>>>> - * @max_state:        The size of freq_table.
>>>>>>>> - * @total_trans:    Number of devfreq transitions
>>>>>>>> - * @trans_table:    Statistics of devfreq transitions
>>>>>>>> - * @time_in_state:    Statistics of devfreq states
>>>>>>>> - * @last_time:        The last time stats were updated
>>>>>>>> - * @stats_lock:        Lock protecting trans_table, time_in_state,
>>>>>>>> - *            last_time and total_trans used for statistics
>>>>>>>> + * @stats:        Statistics of devfreq states and state transitions
>>>>>>>>     */
>>>>>>>>    struct devfreq_dev_profile {
>>>>>>>>        unsigned long initial_freq;
>>>>>>>> @@ -108,14 +124,7 @@ struct devfreq_dev_profile {
>>>>>>>>        int (*get_cur_freq)(struct device *dev, unsigned long *freq);
>>>>>>>>        void (*exit)(struct device *dev);
>>>>>>>>    -    unsigned long *freq_table;
>>>>>>>> -    unsigned int max_state;
>>>>>>>> -    /* information for device frequency transition */
>>>>>>>> -    unsigned int total_trans;
>>>>>>>> -    unsigned int *trans_table;
>>>>>>>> -    u64 *time_in_state;
>>>>>>>> -    unsigned long long last_time;
>>>>>>>> -    spinlock_t stats_lock;
>>>>>>>> +    struct devfreq_stats *stats;
>>>>>>>>    };
>>>>>>>>      /**
>>>>>>>>
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