cpufreq:LAB: Introduce new cpufreq LAB(Legaccy Application Boost) governor

This patch introduces new cpufreq governor named 'LAB'.
LAB governor will use scheduler, per-CPU information to determine how many
CPUs are in busy now. As a result the number of idle CPUs is calculated
for current load (digital low pass filtering is used to provide more stable
results). It will determine next frequency.

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>

Conflicts:

	drivers/cpufreq/cpufreq_governor.c
Resolved-by: MyungJoo Ham <myungjoo.ham@samsung.com>

6 files changed, 464 insertions, 32 deletions

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 79ebd97b04f..9ee9d3cdda8 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -116,6 +116,18 @@ config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
 	  Be aware that not all cpufreq drivers support the conservative
 	  governor. If unsure have a look at the help section of the
 	  driver. Fallback governor will be the performance governor.
+
+config CPU_FREQ_DEFAULT_GOV_LAB
+	bool "lab"
+	select CPU_FREQ_GOV_LAB
+	select CPU_FREQ_GOV_PERFORMANCE
+	help
+	  Use the CPUFreq governor 'lab' as default. This allows
+	  you to get a full dynamic frequency capable system by simply
+	  loading your cpufreq low-level hardware driver.
+	  Be aware that not all cpufreq drivers support the lab governor.
+	  If unsure have a look at the help section of the driver.
+	  Fallback governor will be the performance governor.
 endchoice
 
 config CPU_FREQ_GOV_PERFORMANCE
@@ -198,6 +210,20 @@ config CPU_FREQ_GOV_CONSERVATIVE
 
 	  If in doubt, say N.
 
+config CPU_FREQ_GOV_LAB
+	tristate "'lab' cpufreq policy governor"
+	select CPU_FREQ_TABLE
+	select CPU_FREQ_GOV_COMMON
+	help
+	  'lab' - This driver adds a dynamic cpufreq policy governor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cpufreq_ondemand.
+
+	  For details, take a look at linux/Documentation/cpu-freq.
+
+	  If in doubt, say N.
+
 config GENERIC_CPUFREQ_CPU0
 	tristate "Generic CPU0 cpufreq driver"
 	depends on HAVE_CLK && REGULATOR && PM_OPP && OF
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 315b9231feb..d8252a7bf7e 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_POWERSAVE)	+= cpufreq_powersave.o
 obj-$(CONFIG_CPU_FREQ_GOV_USERSPACE)	+= cpufreq_userspace.o
 obj-$(CONFIG_CPU_FREQ_GOV_ONDEMAND)	+= cpufreq_ondemand.o
 obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)	+= cpufreq_conservative.o
+obj-$(CONFIG_CPU_FREQ_GOV_LAB)		+= cpufreq_lab.o
 obj-$(CONFIG_CPU_FREQ_GOV_COMMON)		+= cpufreq_governor.o
 
 # CPUfreq cross-arch helpers
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index a593bb49731..86a3816bb0f 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -148,6 +148,13 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 
 		load = 100 * (wall_time - idle_time) / wall_time;
 
+		if (dbs_data->cdata->governor == GOV_LAB) {
+			struct lb_cpu_dbs_info_s *lb_dbs_info =
+				dbs_data->cdata->get_cpu_dbs_info_s(j);
+
+			lb_dbs_info->idle_time = (100 * idle_time) / wall_time;
+		}
+
 		if (dbs_data->cdata->governor == GOV_ONDEMAND) {
 			int freq_avg = __cpufreq_driver_getavg(policy, j);
 			if (freq_avg <= 0)
@@ -235,13 +242,16 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 	struct dbs_data *dbs_data;
 	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
 	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
+	struct lb_cpu_dbs_info_s *lb_dbs_info = NULL;
 	struct od_ops *od_ops = NULL;
 	struct od_dbs_tuners *od_tuners = NULL;
 	struct cs_dbs_tuners *cs_tuners = NULL;
+	struct lb_dbs_tuners *lb_tuners = NULL;
 	struct cpu_dbs_common_info *cpu_cdbs;
-	unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
+	unsigned int sampling_rate = 0, ignore_nice = 0, latency, j, cpu = policy->cpu;
 	int io_busy = 0;
 	int rc;
+	int governor = cdata->governor;
 
 	if (have_governor_per_policy())
 		dbs_data = policy->governor_data;
@@ -299,7 +309,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
 					latency * LATENCY_MULTIPLIER));
 
-		if ((cdata->governor == GOV_CONSERVATIVE) &&
+		if ((governor == GOV_CONSERVATIVE) &&
 				(!policy->governor->initialized)) {
 			struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 
@@ -319,7 +329,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			if (!have_governor_per_policy())
 				cpufreq_put_global_kobject();
 
-			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
+			if ((governor == GOV_CONSERVATIVE) &&
 				(policy->governor->initialized == 1)) {
 				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 
@@ -338,25 +348,37 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 
 	cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
 
-	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-		cs_tuners = dbs_data->tuners;
-		cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
-		sampling_rate = cs_tuners->sampling_rate;
-		ignore_nice = cs_tuners->ignore_nice_load;
-	} else {
-		od_tuners = dbs_data->tuners;
-		od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
-		sampling_rate = od_tuners->sampling_rate;
-		ignore_nice = od_tuners->ignore_nice_load;
-		od_ops = dbs_data->cdata->gov_ops;
-		io_busy = od_tuners->io_is_busy;
-	}
-
 	switch (event) {
 	case CPUFREQ_GOV_START:
 		if (!policy->cur)
 			return -EINVAL;
 
+		if (governor == GOV_CONSERVATIVE) {
+			cs_tuners = dbs_data->tuners;
+			cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+			cs_dbs_info->down_skip = 0;
+			cs_dbs_info->requested_freq = policy->cur;
+			sampling_rate = cs_tuners->sampling_rate;
+			ignore_nice = cs_tuners->ignore_nice_load;
+			cs_dbs_info->enable = 1;
+		} else if (governor == GOV_ONDEMAND) {
+			od_tuners = dbs_data->tuners;
+			od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+			od_dbs_info->rate_mult = 1;
+			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+			sampling_rate = od_tuners->sampling_rate;
+			ignore_nice = od_tuners->ignore_nice_load;
+			od_ops = dbs_data->cdata->gov_ops;
+			io_busy = od_tuners->io_is_busy;
+			od_ops->powersave_bias_init_cpu(cpu);
+		} else {
+			lb_tuners = dbs_data->tuners;
+			lb_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+			lb_dbs_info->rate_mult = 1;
+			sampling_rate = lb_tuners->sampling_rate;
+			ignore_nice = lb_tuners->ignore_nice;
+		}
+
 		mutex_lock(&dbs_data->mutex);
 
 		for_each_cpu(j, policy->cpus) {
@@ -376,20 +398,6 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 					     dbs_data->cdata->gov_dbs_timer);
 		}
 
-		/*
-		 * conservative does not implement micro like ondemand
-		 * governor, thus we are bound to jiffes/HZ
-		 */
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-			cs_dbs_info->down_skip = 0;
-			cs_dbs_info->enable = 1;
-			cs_dbs_info->requested_freq = policy->cur;
-		} else {
-			od_dbs_info->rate_mult = 1;
-			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
-			od_ops->powersave_bias_init_cpu(cpu);
-		}
-
 		mutex_unlock(&dbs_data->mutex);
 
 		/* Initiate timer time stamp */
@@ -400,7 +408,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		break;
 
 	case CPUFREQ_GOV_STOP:
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
+		if (governor == GOV_CONSERVATIVE)
 			cs_dbs_info->enable = 0;
 
 		gov_cancel_work(dbs_data, policy);
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index 0d9e6befe1d..09d9603edb5 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -163,6 +163,14 @@ struct cs_cpu_dbs_info_s {
 	unsigned int enable:1;
 };
 
+struct lb_cpu_dbs_info_s {
+	struct cpu_dbs_common_info cdbs;
+	u64 prev_cpu_iowait;
+	struct cpufreq_frequency_table *freq_table;
+	unsigned int rate_mult;
+	unsigned int idle_time;
+};
+
 /* Per policy Governers sysfs tunables */
 struct od_dbs_tuners {
 	unsigned int ignore_nice_load;
@@ -183,12 +191,21 @@ struct cs_dbs_tuners {
 	unsigned int freq_step;
 };
 
+struct lb_dbs_tuners {
+	unsigned int ignore_nice;
+	unsigned int sampling_rate;
+	unsigned int sampling_down_factor;
+	unsigned int up_threshold;
+	unsigned int adj_up_threshold;
+};
+
 /* Common Governer data across policies */
 struct dbs_data;
 struct common_dbs_data {
 	/* Common across governors */
 	#define GOV_ONDEMAND		0
 	#define GOV_CONSERVATIVE	1
+	#define GOV_LAB			2
 	int governor;
 	struct attribute_group *attr_group_gov_sys; /* one governor - system */
 	struct attribute_group *attr_group_gov_pol; /* one governor - policy */
diff --git a/drivers/cpufreq/cpufreq_lab.c b/drivers/cpufreq/cpufreq_lab.c
new file mode 100644
index 00000000000..3fe876ba3cb
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_lab.c
@@ -0,0 +1,377 @@
+/*
+ *  drivers/cpufreq/cpufreq_lab.c
+ *
+ *  LAB(Legacy Application Boost) cpufreq governor
+ *
+ *  Copyright (C) SAMSUNG Electronics. CO.
+ *		Jonghwa Lee <jonghw3.lee@samusng.com>
+ *		Lukasz Majewski <l.majewski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/percpu-defs.h>
+#include <linux/sysfs.h>
+#include <linux/tick.h>
+#include <linux/types.h>
+#include <linux/cpuidle.h>
+#include <linux/slab.h>
+
+#include "cpufreq_governor.h"
+
+#define DEF_FREQUENCY_DOWN_DIFFERENTIAL		(10)
+#define DEF_FREQUENCY_UP_THRESHOLD		(80)
+#define DEF_SAMPLING_DOWN_FACTOR		(1)
+#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL	(3)
+#define MICRO_FREQUENCY_UP_THRESHOLD		(95)
+#define MICRO_FREQUENCY_MIN_SAMPLE_RATE		(10000)
+
+#define MAX_HIST		5
+#define FREQ_STEP		50000
+#define IDLE_THRESHOLD		90
+
+/* Pre-calculated summation of weight, 0.5
+ * 1
+ * 1 + 0.5^1 = 1.5
+ * 1 + 0.5^1 + 0.5^2 = 1.75
+ * 1 + 0.5^1 + 0.5^2 + 0.5^3 = 1.87
+ * 1 + 0.5^1 + 0.5^2 + 0.5^3 + 0.5^4 = 1.93
+ */
+static int history_weight_sum[] = { 100, 150, 175, 187, 193 };
+
+static unsigned int idle_avg[NR_CPUS];
+static unsigned int idle_hist[NR_CPUS][MAX_HIST];
+
+static DEFINE_PER_CPU(struct lb_cpu_dbs_info_s, lb_cpu_dbs_info);
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_LAB
+static struct cpufreq_governor cpufreq_gov_lab;
+#endif
+
+/* Single polynomial approx -> all CPUs busy */
+static int a_all = -6, b_all = 1331;
+/* Single polynomial approx -> one CPUs busy */
+static int a_one = 10, b_one = 205;
+/* Single polynomial approx -> 2,3... CPUs busy */
+static int a_rest = 4, b_rest1 = 100, b_rest2 = 300;
+/* Polynomial divider */
+static int poly_div = 1024;
+
+static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
+{
+	if (p->cur == freq)
+		return;
+
+	__cpufreq_driver_target(p, freq, CPUFREQ_RELATION_L);
+}
+
+/* Calculate average of idle time with weighting 50% less to older one.
+ * With weight, average can be affected by current phase more rapidly than
+ * normal average. And it also has tolerance for temporary fluctuation of
+ * idle time as normal average has.
+ *
+ * Weigted average = sum(ai * wi) / sum(wi)
+ */
+static inline int cpu_idle_calc_avg(unsigned int *p, int size)
+{
+	int i, sum;
+
+	for (i = 0, sum = 0; i < size; p++, i++) {
+		sum += *p;
+		*p >>= 1;
+	}
+	sum *= 100;
+
+	return (int) (sum / history_weight_sum[size - 1]);
+}
+
+/*
+ * LAB governor policy adjustement
+ */
+static void lb_check_cpu(int cpu, unsigned int load_freq)
+{
+	struct lb_cpu_dbs_info_s *dbs_info = &per_cpu(lb_cpu_dbs_info, cpu);
+	struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
+	int i, idx, idle_cpus = 0, b = 0;
+	static int cnt = 0;
+	unsigned int freq = 0;
+
+	idx = cnt++ % MAX_HIST;
+
+	for_each_possible_cpu(i) {
+		struct lb_cpu_dbs_info_s *dbs_cpu_info =
+			&per_cpu(lb_cpu_dbs_info, i);
+
+		idle_hist[i][idx] = dbs_cpu_info->idle_time;
+		idle_avg[i] = cpu_idle_calc_avg(idle_hist[i],
+					cnt < MAX_HIST ? cnt : MAX_HIST);
+
+		if (idle_avg[i] > IDLE_THRESHOLD)
+			idle_cpus++;
+	}
+
+	if (idle_cpus < 0 || idle_cpus > NR_CPUS) {
+		pr_warn("idle_cpus: %d out of range\n", idle_cpus);
+		return;
+	}
+
+	if (idle_cpus == 0) {
+		/* Full load -> reduce freq */
+		freq = policy->max * (a_all * load_freq + b_all) / poly_div;
+	} else if (idle_cpus == NR_CPUS) {
+		/* Idle cpus */
+		freq = policy->min;
+	} else if (idle_cpus == (NR_CPUS - 1)) {
+		freq = policy->max * (a_one * load_freq + b_one) / poly_div;
+	} else {
+		/* Adjust frequency with number of available CPUS */
+		/* smaller idle_cpus -> smaller frequency */
+		b = ((idle_cpus - 1) * b_rest1) + b_rest2;
+		freq = policy->max * (a_rest * load_freq + b) / poly_div;
+	}
+#if 0 
+	if (!idx)
+		pr_info("p->max:%d,freq: %d,idle_cpus: %d,avg : %d %d %d %d load_f: %d\n",
+		       policy->max, freq, idle_cpus, idle_avg[0], idle_avg[1],
+			idle_avg[2], idle_avg[3], load_freq);
+#endif
+
+	dbs_freq_increase(policy, freq);
+}
+
+static void lb_dbs_timer(struct work_struct *work)
+{
+	struct lb_cpu_dbs_info_s *dbs_info =
+		container_of(work, struct lb_cpu_dbs_info_s, cdbs.work.work);
+	unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
+	struct lb_cpu_dbs_info_s *core_dbs_info = &per_cpu(lb_cpu_dbs_info,
+			cpu);
+	struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data;
+	struct lb_dbs_tuners *lb_tuners = dbs_data->tuners;
+	int delay;
+
+	mutex_lock(&core_dbs_info->cdbs.timer_mutex);
+
+	dbs_check_cpu(dbs_data, cpu);
+
+	delay = delay_for_sampling_rate(lb_tuners->sampling_rate
+						* core_dbs_info->rate_mult);
+
+	gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, false);
+	mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
+}
+
+/************************** sysfs interface ************************/
+static struct common_dbs_data lb_dbs_cdata;
+
+/**
+ * update_sampling_rate - update sampling rate effective immediately if needed.
+ * @new_rate: new sampling rate
+ *
+ * If new rate is smaller than the old, simply updating
+ * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
+ * original sampling_rate was 1 second and the requested new sampling rate is 10
+ * ms because the user needs immediate reaction from lab governor, but not
+ * sure if higher frequency will be required or not, then, the governor may
+ * change the sampling rate too late; up to 1 second later. Thus, if we are
+ * reducing the sampling rate, we need to make the new value effective
+ * immediately.
+ */
+static void update_sampling_rate(struct dbs_data *dbs_data,
+			unsigned int new_rate)
+{
+	struct lb_dbs_tuners *lb_tuners = dbs_data->tuners;
+	int cpu;
+
+	lb_tuners->sampling_rate = new_rate = max(new_rate,
+			dbs_data->min_sampling_rate);
+
+	for_each_online_cpu(cpu) {
+		struct cpufreq_policy *policy;
+		struct lb_cpu_dbs_info_s *dbs_info;
+		unsigned long next_sampling, appointed_at;
+
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy)
+			continue;
+		if (policy->governor != &cpufreq_gov_lab) {
+			cpufreq_cpu_put(policy);
+			continue;
+		}
+		dbs_info = &per_cpu(lb_cpu_dbs_info, cpu);
+		cpufreq_cpu_put(policy);
+
+		mutex_lock(&dbs_info->cdbs.timer_mutex);
+
+		if (!delayed_work_pending(&dbs_info->cdbs.work)) {
+			mutex_unlock(&dbs_info->cdbs.timer_mutex);
+			continue;
+		}
+
+		next_sampling = jiffies + usecs_to_jiffies(new_rate);
+		appointed_at = dbs_info->cdbs.work.timer.expires;
+
+		if (time_before(next_sampling, appointed_at)) {
+
+			mutex_unlock(&dbs_info->cdbs.timer_mutex);
+			cancel_delayed_work_sync(&dbs_info->cdbs.work);
+			mutex_lock(&dbs_info->cdbs.timer_mutex);
+
+			schedule_delayed_work_on(cpu, &dbs_info->cdbs.work,
+					usecs_to_jiffies(new_rate));
+
+		}
+		mutex_unlock(&dbs_info->cdbs.timer_mutex);
+	}
+}
+
+static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+				size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	update_sampling_rate(dbs_data, input);
+	return count;
+}
+
+show_store_one(lb, sampling_rate);
+gov_sys_pol_attr_rw(sampling_rate);
+
+static struct attribute *dbs_attributes_gov_sys[] = {
+	&sampling_rate_gov_sys.attr,
+	NULL
+};
+
+static struct attribute_group lb_attr_group_gov_sys = {
+	.attrs = dbs_attributes_gov_sys,
+	.name = "lab",
+};
+
+static struct attribute *dbs_attributes_gov_pol[] = {
+	&sampling_rate_gov_pol.attr,
+	NULL
+};
+
+static struct attribute_group lb_attr_group_gov_pol = {
+	.attrs = dbs_attributes_gov_pol,
+	.name = "lab",
+};
+
+/************************** sysfs end ************************/
+
+static int lb_init(struct dbs_data *dbs_data)
+{
+	struct lb_dbs_tuners *tuners;
+	u64 idle_time;
+	int cpu;
+
+	tuners = kzalloc(sizeof(struct od_dbs_tuners), GFP_KERNEL);
+	if (!tuners) {
+		pr_err("%s: kzalloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	cpu = get_cpu();
+	idle_time = get_cpu_idle_time_us(cpu, NULL);
+	put_cpu();
+	if (idle_time != -1ULL) {
+		/* Idle micro accounting is supported. Use finer thresholds */
+		tuners->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
+		tuners->adj_up_threshold = MICRO_FREQUENCY_UP_THRESHOLD -
+			MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
+		/*
+		 * In nohz/micro accounting case we set the minimum frequency
+		 * not depending on HZ, but fixed (very low). The deferred
+		 * timer might skip some samples if idle/sleeping as needed.
+		*/
+		dbs_data->min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
+	} else {
+		tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
+		tuners->adj_up_threshold = DEF_FREQUENCY_UP_THRESHOLD -
+			DEF_FREQUENCY_DOWN_DIFFERENTIAL;
+
+		/* For correct statistics, we need 10 ticks for each measure */
+		dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
+			jiffies_to_usecs(10);
+	}
+
+	tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
+	tuners->ignore_nice = 0;
+
+	dbs_data->tuners = tuners;
+	mutex_init(&dbs_data->mutex);
+	return 0;
+}
+
+static void lb_exit(struct dbs_data *dbs_data)
+{
+	kfree(dbs_data->tuners);
+}
+
+define_get_cpu_dbs_routines(lb_cpu_dbs_info);
+
+static struct common_dbs_data lb_dbs_data = {
+	.governor = GOV_LAB,
+	.attr_group_gov_sys = &lb_attr_group_gov_sys,
+	.attr_group_gov_pol = &lb_attr_group_gov_pol,
+	.get_cpu_cdbs = get_cpu_cdbs,
+	.get_cpu_dbs_info_s = get_cpu_dbs_info_s,
+	.gov_dbs_timer = lb_dbs_timer,
+	.gov_check_cpu = lb_check_cpu,
+	.init = lb_init,
+	.exit = lb_exit,
+};
+
+static int lb_cpufreq_governor_dbs(struct cpufreq_policy *policy,
+		unsigned int event)
+{
+	return cpufreq_governor_dbs(policy, &lb_dbs_data, event);
+}
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_LAB
+static
+#endif
+struct cpufreq_governor cpufreq_gov_lab = {
+	.name			= "lab",
+	.governor		= lb_cpufreq_governor_dbs,
+	.max_transition_latency	= TRANSITION_LATENCY_LIMIT,
+	.owner			= THIS_MODULE,
+};
+
+static int __init cpufreq_gov_dbs_init(void)
+{
+	return cpufreq_register_governor(&cpufreq_gov_lab);
+}
+
+static void __exit cpufreq_gov_dbs_exit(void)
+{
+	cpufreq_unregister_governor(&cpufreq_gov_lab);
+}
+
+MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
+MODULE_AUTHOR("Lukasz Majewski <l.majewski@samsung.com>");
+MODULE_DESCRIPTION("'cpufreq_lab' - A dynamic cpufreq governor for "
+		"Legacy Application Boosting");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_LAB
+fs_initcall(cpufreq_gov_dbs_init);
+#else
+module_init(cpufreq_gov_dbs_init);
+#endif
+module_exit(cpufreq_gov_dbs_exit);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index dbf5744eb56..6b076e37a99 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -403,6 +403,9 @@ extern struct cpufreq_governor cpufreq_gov_ondemand;
 #elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
 extern struct cpufreq_governor cpufreq_gov_conservative;
 #define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_conservative)
+#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_LAB)
+extern struct cpufreq_governor cpufreq_gov_lab;
+#define CPUFREQ_DEFAULT_GOVERNOR	(&cpufreq_gov_lab)
 #endif