Re: [PATCH 7/7] devfreq: move statistics to separate struct
From: Chanwoo Choi
Date: Fri Nov 15 2019 - 01:15:25 EST
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.
>>
>>> 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;
>>>> };
>>>>
>>>> /**
>>>>
>>
>>
>
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics