[PATCH v3 1/3] devfreq: change time stats to 64-bit

From: Kamil Konieczny <k.konieczny@samsung.com>
To: k.konieczny@samsung.com
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	MyungJoo Ham <myungjoo.ham@samsung.com>
Subject: [PATCH v3 1/3] devfreq: change time stats to 64-bit
Date: Thu,  5 Dec 2019 15:55:25 +0100	[thread overview]
Message-ID: <20191205145527.26117-2-k.konieczny@samsung.com> (raw)
In-Reply-To: <20191205145527.26117-1-k.konieczny@samsung.com>

Change time stats counting to bigger type by using 64-bit jiffies.
This will make devfreq stats code look similar to cpufreq stats and
prevents overflow (for HZ = 1000 after 49.7 days).

Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
---
Changes in v3:
- changed types of cur_time and last_stats_updated to u64 as this is
  returned by get_jiffies_64()

Changes in v2:
- added Acked-by, rebased on linux-next
---
 drivers/devfreq/devfreq.c | 14 +++++++-------
 include/linux/devfreq.h   |  4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index bdeb4189c978..abecadeb3dc2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -199,10 +199,10 @@ static int set_freq_table(struct devfreq *devfreq)
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev, prev_lev, ret = 0;
-	unsigned long cur_time;
+	u64 cur_time;
 
 	lockdep_assert_held(&devfreq->lock);
-	cur_time = jiffies;
+	cur_time = get_jiffies_64();
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq)
@@ -525,7 +525,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
 out_update:
-	devfreq->last_stat_updated = jiffies;
+	devfreq->last_stat_updated = get_jiffies_64();
 	devfreq->stop_polling = false;
 
 	if (devfreq->profile->get_cur_freq &&
@@ -748,7 +748,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
-			sizeof(unsigned long),
+			sizeof(*devfreq->time_in_state),
 			GFP_KERNEL);
 	if (!devfreq->time_in_state) {
 		mutex_unlock(&devfreq->lock);
@@ -756,7 +756,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_devfreq;
 	}
 
-	devfreq->last_stat_updated = jiffies;
+	devfreq->last_stat_updated = get_jiffies_64();
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1470,8 +1470,8 @@ static ssize_t trans_stat_show(struct device *dev,
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
 				devfreq->trans_table[(i * max_state) + j]);
-		len += sprintf(buf + len, "%10u\n",
-			jiffies_to_msecs(devfreq->time_in_state[i]));
+		len += sprintf(buf + len, "%10llu\n", (u64)
+			jiffies64_to_msecs(devfreq->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2bae9ed3c783..41f15e7a22b8 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -174,8 +174,8 @@ struct devfreq {
 	/* information for device frequency transition */
 	unsigned int total_trans;
 	unsigned int *trans_table;
-	unsigned long *time_in_state;
-	unsigned long last_stat_updated;
+	u64 *time_in_state;
+	u64 last_stat_updated;
 
 	struct srcu_notifier_head transition_notifier_list;
 };
-- 
2.24.0

