Re: [PATCH 7/7] devfreq: move statistics to separate struct
From: Bartlomiej Zolnierkiewicz
Date: Fri Nov 15 2019 - 07:40:49 EST
[ added Zhang, Eduardo, Ãrjan 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?
It has been merged in the following commit:
commit a76caf55e5b356ba20a5a43ac4d9f7a04b20941d
Author: Ãrjan Eide <orjan.eide@xxxxxxx>
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@xxxxxxxxx>
Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
Signed-off-by: Javi Merino <javi.merino@xxxxxxx>
Signed-off-by: Ãrjan Eide <orjan.eide@xxxxxxx>
Signed-off-by: Eduardo Valentin <edubezval@xxxxxxxxx>
...
but 4 years later there is still no single in-kernel user for this code?
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@xxxxxxxxxxx>
>>>>> ---
>>>>> 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;
>>>>> };
>>>>>
>>>>> /**
>>>>>