[PATCH v3 3/3] devfreq: move statistics to separate struct

From: Kamil Konieczny
Date: Thu Dec 05 2019 - 09:55:54 EST


Count time and transitions between devfreq frequencies in separate struct
for improved code readability and maintenance.

Signed-off-by: Kamil Konieczny <k.konieczny@xxxxxxxxxxx>
Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
Changes in v3:
- removed freq_table and max_state from struct devfreq_stats as they are
already present in struct devfreq_dev_profile
- renamed last_stat_updated to last_update, as 'stat' is already present
in struct devfreq_stats
- define struct devfreq_stats stats; in devfreq as there is only one
stats per devfreq
- improve descriptions of devfreq_stats and stats
- use profile instead of devfreq->profile in devfreq_add_device, as this
var is already parameter
- added Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>

Changes in v2:
- squash three patches into one, do not modify devfreq_profile and separate stats
into devfreq_stats
---
drivers/devfreq/devfreq.c | 67 ++++++++++++++++++++-------------------
include/linux/devfreq.h | 26 +++++++++------
2 files changed, 51 insertions(+), 42 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 218eb64d7f28..bcd7e92d2cf3 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -198,6 +198,7 @@ static int set_freq_table(struct devfreq *devfreq)
*/
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
{
+ struct devfreq_stats *stats = &devfreq->stats;
int lev, prev_lev, ret = 0;
u64 cur_time;

@@ -214,9 +215,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
goto out;
}

- devfreq->time_in_state[prev_lev] +=
- cur_time - devfreq->last_stat_updated;
-
+ stats->time_in_state[prev_lev] += cur_time - stats->last_update;
lev = devfreq_get_freq_level(devfreq, freq);
if (lev < 0) {
ret = lev;
@@ -224,13 +223,13 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
}

if (lev != prev_lev) {
- devfreq->trans_table[(prev_lev *
- devfreq->profile->max_state) + lev]++;
- devfreq->total_trans++;
+ stats->trans_table[(prev_lev * devfreq->profile->max_state) +
+ lev]++;
+ stats->total_trans++;
}

out:
- devfreq->last_stat_updated = cur_time;
+ stats->last_update = cur_time;
return ret;
}
EXPORT_SYMBOL(devfreq_update_status);
@@ -525,7 +524,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
msecs_to_jiffies(devfreq->profile->polling_ms));

out_update:
- devfreq->last_stat_updated = get_jiffies_64();
+ devfreq->stats.last_update = get_jiffies_64();
devfreq->stop_polling = false;

if (devfreq->profile->get_cur_freq &&
@@ -735,28 +734,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
goto err_out;
}

- devfreq->trans_table = devm_kzalloc(&devfreq->dev,
+ devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
array3_size(sizeof(unsigned int),
- devfreq->profile->max_state,
- devfreq->profile->max_state),
+ profile->max_state,
+ profile->max_state),
GFP_KERNEL);
- if (!devfreq->trans_table) {
+ if (!devfreq->stats.trans_table) {
mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}

- devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
- devfreq->profile->max_state,
- sizeof(*devfreq->time_in_state),
+ devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
+ profile->max_state,
+ sizeof(*devfreq->stats.time_in_state),
GFP_KERNEL);
- if (!devfreq->time_in_state) {
+ if (!devfreq->stats.time_in_state) {
mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}

- devfreq->last_stat_updated = get_jiffies_64();
+ devfreq->stats.last_update = get_jiffies_64();
+ devfreq->stats.total_trans = 0;

srcu_init_notifier_head(&devfreq->transition_notifier_list);

@@ -1435,9 +1435,11 @@ static ssize_t trans_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct devfreq *devfreq = to_devfreq(dev);
+ struct devfreq_stats *stats = &devfreq->stats;
+ unsigned int max_state = devfreq->profile->max_state;
+ unsigned long *freq_table = devfreq->profile->freq_table;
ssize_t len;
int i, j;
- unsigned int max_state = devfreq->profile->max_state;

if (max_state == 0)
return sprintf(buf, "Not Supported.\n");
@@ -1453,29 +1455,27 @@ static ssize_t trans_stat_show(struct device *dev,
len = sprintf(buf, " From : To\n");
len += sprintf(buf + len, " :");
for (i = 0; i < max_state; i++)
- len += sprintf(buf + len, "%10lu",
- devfreq->profile->freq_table[i]);
+ len += sprintf(buf + len, "%10lu", freq_table[i]);

len += sprintf(buf + len, " time(ms)\n");

for (i = 0; i < max_state; i++) {
- if (devfreq->profile->freq_table[i]
- == devfreq->previous_freq) {
+ if (freq_table[i] == devfreq->previous_freq)
len += sprintf(buf + len, "*");
- } else {
+ else
len += sprintf(buf + len, " ");
- }
- len += sprintf(buf + len, "%10lu:",
- devfreq->profile->freq_table[i]);
+
+ len += sprintf(buf + len, "%10lu:", freq_table[i]);
for (j = 0; j < max_state; j++)
len += sprintf(buf + len, "%10u",
- devfreq->trans_table[(i * max_state) + j]);
+ stats->trans_table[(i * max_state) + j]);
+
len += sprintf(buf + len, "%10llu\n", (u64)
- jiffies64_to_msecs(devfreq->time_in_state[i]));
+ jiffies64_to_msecs(stats->time_in_state[i]));
}

len += sprintf(buf + len, "Total transition : %u\n",
- devfreq->total_trans);
+ stats->total_trans);
return len;
}

@@ -1484,6 +1484,7 @@ static ssize_t trans_stat_store(struct device *dev,
const char *buf, size_t count)
{
struct devfreq *df = to_devfreq(dev);
+ struct devfreq_stats *stats = &df->stats;
unsigned int cnt = df->profile->max_state;
int err, value;

@@ -1495,10 +1496,10 @@ static ssize_t trans_stat_store(struct device *dev,
return count;

mutex_lock(&df->lock);
- memset(df->time_in_state, 0, cnt * sizeof(u64));
- memset(df->trans_table, 0, cnt * cnt * sizeof(int));
- df->last_stat_updated = get_jiffies_64();
- df->total_trans = 0;
+ memset(stats->time_in_state, 0, cnt * sizeof(u64));
+ memset(stats->trans_table, 0, cnt * cnt * sizeof(int));
+ stats->last_update = get_jiffies_64();
+ stats->total_trans = 0;
mutex_unlock(&df->lock);

return count;
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 41f15e7a22b8..de2fdc56aa5b 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -106,6 +106,20 @@ struct devfreq_dev_profile {
unsigned int max_state;
};

+/**
+ * struct devfreq_stats - Statistics of devfreq device behavior
+ * @total_trans: Number of devfreq transitions.
+ * @trans_table: Statistics of devfreq transitions.
+ * @time_in_state: Statistics of devfreq states.
+ * @last_update: The last time stats were updated.
+ */
+struct devfreq_stats {
+ unsigned int total_trans;
+ unsigned int *trans_table;
+ u64 *time_in_state;
+ u64 last_update;
+};
+
/**
* struct devfreq - Device devfreq structure
* @node: list node - contains the devices with devfreq that have been
@@ -131,10 +145,7 @@ struct devfreq_dev_profile {
* @suspend_freq: frequency of a device set during suspend phase.
* @resume_freq: frequency of a device set in resume phase.
* @suspend_count: suspend requests counter for a device.
- * @total_trans: Number of devfreq transitions
- * @trans_table: Statistics of devfreq transitions
- * @time_in_state: Statistics of devfreq states
- * @last_stat_updated: The last time stat updated
+ * @stats: Statistics of devfreq device behavior
* @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
*
* This structure stores the devfreq information for a give device.
@@ -171,11 +182,8 @@ struct devfreq {
unsigned long resume_freq;
atomic_t suspend_count;

- /* information for device frequency transition */
- unsigned int total_trans;
- unsigned int *trans_table;
- u64 *time_in_state;
- u64 last_stat_updated;
+ /* information for device frequency transitions */
+ struct devfreq_stats stats;

struct srcu_notifier_head transition_notifier_list;
};
--
2.24.0