cpuquiet: Make stats optional

Make the per CPU statistics a configureable option.

bug 1049625

Change-Id: I28b248bbbad89a19e8d8d69400733dfd4a2cf052
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
(cherry picked from commit 94ade9be87aeda9353808d0f9331acf3e3639d3a)
Reviewed-on: http://git-master/r/#change,168749
Reviewed-on: http://git-master/r/206801
Tested-by: Ilan Aelion <iaelion@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>

2 files changed, 56 insertions, 33 deletions

diff --git a/drivers/cpuquiet/Kconfig b/drivers/cpuquiet/Kconfig
index a2025baedf41..34416b1a227c 100644
--- a/drivers/cpuquiet/Kconfig
+++ b/drivers/cpuquiet/Kconfig
@@ -10,6 +10,15 @@ config CPUQUIET_FRAMEWORK
 
 if CPUQUIET_FRAMEWORK
 
+config CPUQUIET_STATS
+	bool "per CPU statistics"
+	default n
+	help
+	  Enable up/down count and total time plugged statistics per CPU. These
+	  depend on correct driver input for reliability
+
+	  If in doubt say N.
+
 config CPUQUIET_GOVERNOR_USERSPACE
 	bool "userspace"
 	default y
diff --git a/drivers/cpuquiet/driver.c b/drivers/cpuquiet/driver.c
index 4b888fa97be2..fc83fa8cd022 100644
--- a/drivers/cpuquiet/driver.c
+++ b/drivers/cpuquiet/driver.c
@@ -26,6 +26,9 @@
 
 #include "cpuquiet.h"
 
+static struct cpuquiet_driver *cpuquiet_curr_driver;
+
+#ifdef CONFIG_CPUQUIET_STATS
 struct cpuquiet_cpu_stat {
 	cputime64_t time_up_total;
 	u64 last_update;
@@ -33,14 +36,13 @@ struct cpuquiet_cpu_stat {
 	struct kobject cpu_kobject;
 };
 
+struct cpuquiet_cpu_stat *stats;
+
 struct cpu_attribute {
 	struct attribute attr;
 	enum { up_down_count, time_up_total } type;
 };
 
-static struct cpuquiet_driver *cpuquiet_curr_driver;
-struct cpuquiet_cpu_stat *stats;
-
 #define CPU_ATTRIBUTE(_name) \
 	static struct cpu_attribute _name ## _attr = {			\
 		.attr =  {.name = __stringify(_name), .mode = 0444 },	\
@@ -70,34 +72,6 @@ static void stats_update(struct cpuquiet_cpu_stat *stat, bool up)
 	stat->last_update = cur_jiffies;
 }
 
-int cpuquiet_quiesence_cpu(unsigned int cpunumber)
-{
-	int err = -EPERM;
-
-	if (cpuquiet_curr_driver && cpuquiet_curr_driver->quiesence_cpu)
-		err = cpuquiet_curr_driver->quiesence_cpu(cpunumber);
-
-	if (!err)
-		stats_update(stats + cpunumber, 0);
-
-	return err;
-}
-EXPORT_SYMBOL(cpuquiet_quiesence_cpu);
-
-int cpuquiet_wake_cpu(unsigned int cpunumber)
-{
-	int err = -EPERM;
-
-	if (cpuquiet_curr_driver && cpuquiet_curr_driver->wake_cpu)
-		err = cpuquiet_curr_driver->wake_cpu(cpunumber);
-
-	if (!err)
-		stats_update(stats + cpunumber, 1);
-
-	return err;
-}
-EXPORT_SYMBOL(cpuquiet_wake_cpu);
-
 static ssize_t stats_sysfs_show(struct kobject *kobj,
 			struct attribute *attr, char *buf)
 {
@@ -130,31 +104,69 @@ static struct kobj_type ktype_cpu_stats = {
 	.sysfs_ops = &stats_sysfs_ops,
 	.default_attrs = cpu_attributes,
 };
+#endif
+
+int cpuquiet_quiesence_cpu(unsigned int cpunumber)
+{
+	int err = -EPERM;
+
+	if (cpuquiet_curr_driver && cpuquiet_curr_driver->quiesence_cpu)
+		err = cpuquiet_curr_driver->quiesence_cpu(cpunumber);
+
+#ifdef CONFIG_CPUQUIET_STATS
+	if (!err)
+		stats_update(stats + cpunumber, 0);
+#endif
+
+	return err;
+}
+EXPORT_SYMBOL(cpuquiet_quiesence_cpu);
+
+int cpuquiet_wake_cpu(unsigned int cpunumber)
+{
+	int err = -EPERM;
+
+	if (cpuquiet_curr_driver && cpuquiet_curr_driver->wake_cpu)
+		err = cpuquiet_curr_driver->wake_cpu(cpunumber);
+
+#ifdef CONFIG_CPUQUIET_STATS
+	if (!err)
+		stats_update(stats + cpunumber, 1);
+#endif
+
+	return err;
+}
+EXPORT_SYMBOL(cpuquiet_wake_cpu);
 
 int cpuquiet_register_driver(struct cpuquiet_driver *drv)
 {
 	int err = -EBUSY;
 	unsigned int cpu;
 	struct device *dev;
-	u64 cur_jiffies;
 
 	if (!drv)
 		return -EINVAL;
 
+#ifdef CONFIG_CPUQUIET_STATS
 	stats = kzalloc(nr_cpu_ids * sizeof(*stats), GFP_KERNEL);
 	if (!stats)
 		return -ENOMEM;
+#endif
 
 	for_each_possible_cpu(cpu) {
-		cur_jiffies = get_jiffies_64();
+#ifdef CONFIG_CPUQUIET_STATS
+		u64 cur_jiffies = get_jiffies_64();
 		stats[cpu].last_update = cur_jiffies;
 		if (cpu_online(cpu))
 			stats[cpu].up_down_count = 1;
+#endif
 		dev = get_cpu_device(cpu);
 		if (dev) {
 			cpuquiet_add_dev(dev, cpu);
+#ifdef CONFIG_CPUQUIET_STATS
 			cpuquiet_cpu_kobject_init(&stats[cpu].cpu_kobject,
 					&ktype_cpu_stats, "stats", cpu);
+#endif
 		}
 	}
 
@@ -192,7 +204,9 @@ void cpuquiet_unregister_driver(struct cpuquiet_driver *drv)
 	cpuquiet_curr_driver = NULL;
 
 	for_each_possible_cpu(cpu) {
+#ifdef CONFIG_CPUQUIET_STATS
 		kobject_put(&stats[cpu].cpu_kobject);
+#endif
 		cpuquiet_remove_dev(cpu);
 	}