init android origin source code

1 files changed, 775 insertions, 0 deletions

diff --git a/ANDROID_3.4.5/drivers/cpufreq/cpufreq_interactive.c b/ANDROID_3.4.5/drivers/cpufreq/cpufreq_interactive.c
new file mode 100644
index 00000000..c82d9fee
--- /dev/null
+++ b/ANDROID_3.4.5/drivers/cpufreq/cpufreq_interactive.c
@@ -0,0 +1,775 @@
+/*
+ * drivers/cpufreq/cpufreq_interactive.c
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Author: Mike Chan (mike@android.com)
+ *
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <linux/time.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <asm/cputime.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/cpufreq_interactive.h>
+
+static atomic_t active_count = ATOMIC_INIT(0);
+
+struct cpufreq_interactive_cpuinfo {
+	struct timer_list cpu_timer;
+	int timer_idlecancel;
+	u64 time_in_idle;
+	u64 time_in_idle_timestamp;
+	u64 target_set_time;
+	u64 target_set_time_in_idle;
+	struct cpufreq_policy *policy;
+	struct cpufreq_frequency_table *freq_table;
+	unsigned int target_freq;
+	unsigned int floor_freq;
+	u64 floor_validate_time;
+	u64 hispeed_validate_time;
+	int governor_enabled;
+};
+
+static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
+
+/* realtime thread handles frequency scaling */
+static struct task_struct *speedchange_task;
+static cpumask_t speedchange_cpumask;
+static spinlock_t speedchange_cpumask_lock;
+
+/* Hi speed to bump to from lo speed when load burst (default max) */
+static unsigned int hispeed_freq;
+
+/* Go to hi speed when CPU load at or above this value. */
+#define DEFAULT_GO_HISPEED_LOAD 85
+static unsigned long go_hispeed_load;
+
+/* Target load.  Lower values result in higher CPU speeds. */
+#define DEFAULT_TARGET_LOAD 90
+static unsigned long target_load = DEFAULT_TARGET_LOAD;
+
+/*
+ * The minimum amount of time to spend at a frequency before we can ramp down.
+ */
+#define DEFAULT_MIN_SAMPLE_TIME (80 * USEC_PER_MSEC)
+static unsigned long min_sample_time;
+
+/*
+ * The sample rate of the timer used to increase frequency
+ */
+#define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC)
+static unsigned long timer_rate;
+
+/*
+ * Wait this long before raising speed above hispeed, by default a single
+ * timer interval.
+ */
+#define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
+static unsigned long above_hispeed_delay_val;
+
+/*
+ * Non-zero means longer-term speed boost active.
+ */
+
+static int boost_val;
+
+static bool governidle;
+module_param(governidle, bool, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(governidle,
+	"Set to 1 to wake up CPUs from idle to reduce speed (default 0)");
+
+static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
+		unsigned int event);
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
+static
+#endif
+struct cpufreq_governor cpufreq_gov_interactive = {
+	.name = "interactive",
+	.governor = cpufreq_governor_interactive,
+	.max_transition_latency = 10000000,
+	.owner = THIS_MODULE,
+};
+
+static void cpufreq_interactive_timer_resched(
+	struct cpufreq_interactive_cpuinfo *pcpu)
+{
+	mod_timer_pinned(&pcpu->cpu_timer,
+			 jiffies + usecs_to_jiffies(timer_rate));
+	pcpu->time_in_idle =
+		get_cpu_idle_time_us(smp_processor_id(),
+				     &pcpu->time_in_idle_timestamp);
+}
+
+static void cpufreq_interactive_timer(unsigned long data)
+{
+	u64 now;
+	unsigned int delta_idle;
+	unsigned int delta_time;
+	int cpu_load;
+	int load_since_change;
+	struct cpufreq_interactive_cpuinfo *pcpu =
+		&per_cpu(cpuinfo, data);
+	u64 now_idle;
+	unsigned int new_freq;
+	unsigned int index;
+	unsigned long flags;
+
+	smp_rmb();
+
+	if (!pcpu->governor_enabled)
+		goto exit;
+
+	now_idle = get_cpu_idle_time_us(data, &now);
+	delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
+	delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
+
+	/*
+	 * If timer ran less than 1ms after short-term sample started, retry.
+	 */
+	if (delta_time < 1000)
+		goto rearm;
+
+	if (delta_idle > delta_time)
+		cpu_load = 0;
+	else
+		cpu_load = 100 * (delta_time - delta_idle) / delta_time;
+
+	delta_idle = (unsigned int)(now_idle - pcpu->target_set_time_in_idle);
+	delta_time = (unsigned int)(now - pcpu->target_set_time);
+
+	if ((delta_time == 0) || (delta_idle > delta_time))
+		load_since_change = 0;
+	else
+		load_since_change =
+			100 * (delta_time - delta_idle) / delta_time;
+
+	/*
+	 * Choose greater of short-term load (since last idle timer
+	 * started or timer function re-armed itself) or long-term load
+	 * (since last frequency change).
+	 */
+	if (load_since_change > cpu_load)
+		cpu_load = load_since_change;
+
+	if ((cpu_load >= go_hispeed_load || boost_val) &&
+	    pcpu->target_freq < hispeed_freq)
+		new_freq = hispeed_freq;
+	else
+		new_freq = pcpu->policy->cur * cpu_load / target_load;
+
+	if (pcpu->target_freq >= hispeed_freq &&
+	    new_freq > pcpu->target_freq &&
+	    now - pcpu->hispeed_validate_time < above_hispeed_delay_val) {
+		trace_cpufreq_interactive_notyet(
+			data, cpu_load, pcpu->target_freq,
+			pcpu->policy->cur, new_freq);
+		goto rearm;
+	}
+
+	pcpu->hispeed_validate_time = now;
+
+	if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
+					   new_freq, CPUFREQ_RELATION_L,
+					   &index)) {
+		pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
+			     (int) data);
+		goto rearm;
+	}
+
+	new_freq = pcpu->freq_table[index].frequency;
+
+	/*
+	 * Do not scale below floor_freq unless we have been at or above the
+	 * floor frequency for the minimum sample time since last validated.
+	 */
+	if (new_freq < pcpu->floor_freq) {
+		if (now - pcpu->floor_validate_time < min_sample_time) {
+			trace_cpufreq_interactive_notyet(
+				data, cpu_load, pcpu->target_freq,
+				pcpu->policy->cur, new_freq);
+			goto rearm;
+		}
+	}
+
+	pcpu->floor_freq = new_freq;
+	pcpu->floor_validate_time = now;
+
+	if (pcpu->target_freq == new_freq) {
+		trace_cpufreq_interactive_already(
+			data, cpu_load, pcpu->target_freq,
+			pcpu->policy->cur, new_freq);
+		goto rearm_if_notmax;
+	}
+
+	trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
+					 pcpu->policy->cur, new_freq);
+	pcpu->target_set_time_in_idle = now_idle;
+	pcpu->target_set_time = now;
+
+	pcpu->target_freq = new_freq;
+	spin_lock_irqsave(&speedchange_cpumask_lock, flags);
+	cpumask_set_cpu(data, &speedchange_cpumask);
+	spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
+	wake_up_process(speedchange_task);
+
+rearm_if_notmax:
+	/*
+	 * Already set max speed and don't see a need to change that,
+	 * wait until next idle to re-evaluate, don't need timer.
+	 */
+	if (pcpu->target_freq == pcpu->policy->max)
+		goto exit;
+
+rearm:
+	if (!timer_pending(&pcpu->cpu_timer)) {
+		/*
+		 * If governing speed in idle and already at min, cancel the
+		 * timer if that CPU goes idle.  We don't need to re-evaluate
+		 * speed until the next idle exit.
+		 */
+		if (governidle && pcpu->target_freq == pcpu->policy->min)
+			pcpu->timer_idlecancel = 1;
+
+		cpufreq_interactive_timer_resched(pcpu);
+	}
+
+exit:
+	return;
+}
+
+static void cpufreq_interactive_idle_start(void)
+{
+	struct cpufreq_interactive_cpuinfo *pcpu =
+		&per_cpu(cpuinfo, smp_processor_id());
+	int pending;
+
+	if (!pcpu->governor_enabled)
+		return;
+
+	pending = timer_pending(&pcpu->cpu_timer);
+
+	if (pcpu->target_freq != pcpu->policy->min) {
+		/*
+		 * Entering idle while not at lowest speed.  On some
+		 * platforms this can hold the other CPU(s) at that speed
+		 * even though the CPU is idle. Set a timer to re-evaluate
+		 * speed so this idle CPU doesn't hold the other CPUs above
+		 * min indefinitely.  This should probably be a quirk of
+		 * the CPUFreq driver.
+		 */
+		if (!pending) {
+			pcpu->timer_idlecancel = 0;
+			cpufreq_interactive_timer_resched(pcpu);
+		}
+	} else if (governidle) {
+		/*
+		 * If at min speed and entering idle after load has
+		 * already been evaluated, and a timer has been set just in
+		 * case the CPU suddenly goes busy, cancel that timer.  The
+		 * CPU didn't go busy; we'll recheck things upon idle exit.
+		 */
+		if (pending && pcpu->timer_idlecancel) {
+			del_timer(&pcpu->cpu_timer);
+			pcpu->timer_idlecancel = 0;
+		}
+	}
+
+}
+
+static void cpufreq_interactive_idle_end(void)
+{
+	struct cpufreq_interactive_cpuinfo *pcpu =
+		&per_cpu(cpuinfo, smp_processor_id());
+
+	if (!pcpu->governor_enabled)
+		return;
+
+	/* Arm the timer for 1-2 ticks later if not already. */
+	if (!timer_pending(&pcpu->cpu_timer)) {
+		pcpu->timer_idlecancel = 0;
+		cpufreq_interactive_timer_resched(pcpu);
+	} else if (!governidle &&
+		   time_after_eq(jiffies, pcpu->cpu_timer.expires)) {
+		del_timer(&pcpu->cpu_timer);
+		cpufreq_interactive_timer(smp_processor_id());
+	}
+}
+
+static int cpufreq_interactive_speedchange_task(void *data)
+{
+	unsigned int cpu;
+	cpumask_t tmp_mask;
+	unsigned long flags;
+	struct cpufreq_interactive_cpuinfo *pcpu;
+
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		spin_lock_irqsave(&speedchange_cpumask_lock, flags);
+
+		if (cpumask_empty(&speedchange_cpumask)) {
+			spin_unlock_irqrestore(&speedchange_cpumask_lock,
+					       flags);
+			schedule();
+
+			if (kthread_should_stop())
+				break;
+
+			spin_lock_irqsave(&speedchange_cpumask_lock, flags);
+		}
+
+		set_current_state(TASK_RUNNING);
+		tmp_mask = speedchange_cpumask;
+		cpumask_clear(&speedchange_cpumask);
+		spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
+
+		for_each_cpu(cpu, &tmp_mask) {
+			unsigned int j;
+			unsigned int max_freq = 0;
+
+			pcpu = &per_cpu(cpuinfo, cpu);
+			smp_rmb();
+
+			if (!pcpu->governor_enabled)
+				continue;
+
+			for_each_cpu(j, pcpu->policy->cpus) {
+				struct cpufreq_interactive_cpuinfo *pjcpu =
+					&per_cpu(cpuinfo, j);
+
+				if (pjcpu->target_freq > max_freq)
+					max_freq = pjcpu->target_freq;
+			}
+
+			if (max_freq != pcpu->policy->cur)
+				__cpufreq_driver_target(pcpu->policy,
+							max_freq,
+							CPUFREQ_RELATION_H);
+			trace_cpufreq_interactive_setspeed(cpu,
+						     pcpu->target_freq,
+						     pcpu->policy->cur);
+		}
+	}
+
+	return 0;
+}
+
+static void cpufreq_interactive_boost(void)
+{
+	int i;
+	int anyboost = 0;
+	unsigned long flags;
+	struct cpufreq_interactive_cpuinfo *pcpu;
+
+	spin_lock_irqsave(&speedchange_cpumask_lock, flags);
+
+	for_each_online_cpu(i) {
+		pcpu = &per_cpu(cpuinfo, i);
+
+		if (pcpu->target_freq < hispeed_freq) {
+			pcpu->target_freq = hispeed_freq;
+			cpumask_set_cpu(i, &speedchange_cpumask);
+			pcpu->target_set_time_in_idle =
+				get_cpu_idle_time_us(i, &pcpu->target_set_time);
+			pcpu->hispeed_validate_time = pcpu->target_set_time;
+			anyboost = 1;
+		}
+
+		/*
+		 * Set floor freq and (re)start timer for when last
+		 * validated.
+		 */
+
+		pcpu->floor_freq = hispeed_freq;
+		pcpu->floor_validate_time = ktime_to_us(ktime_get());
+	}
+
+	spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
+
+	if (anyboost)
+		wake_up_process(speedchange_task);
+}
+
+static ssize_t show_target_load(
+	struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", target_load);
+}
+
+static ssize_t store_target_load(
+	struct kobject *kobj, struct attribute *attr, const char *buf,
+	size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	target_load = val;
+	return count;
+}
+
+static struct global_attr target_load_attr =
+	__ATTR(target_load, S_IRUGO | S_IWUSR,
+		show_target_load, store_target_load);
+
+static ssize_t show_hispeed_freq(struct kobject *kobj,
+				 struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", hispeed_freq);
+}
+
+static ssize_t store_hispeed_freq(struct kobject *kobj,
+				  struct attribute *attr, const char *buf,
+				  size_t count)
+{
+	int ret;
+	long unsigned int val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	hispeed_freq = val;
+	return count;
+}
+
+static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
+		show_hispeed_freq, store_hispeed_freq);
+
+
+static ssize_t show_go_hispeed_load(struct kobject *kobj,
+				     struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", go_hispeed_load);
+}
+
+static ssize_t store_go_hispeed_load(struct kobject *kobj,
+			struct attribute *attr, const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	go_hispeed_load = val;
+	return count;
+}
+
+static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
+		show_go_hispeed_load, store_go_hispeed_load);
+
+static ssize_t show_min_sample_time(struct kobject *kobj,
+				struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", min_sample_time);
+}
+
+static ssize_t store_min_sample_time(struct kobject *kobj,
+			struct attribute *attr, const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	min_sample_time = val;
+	return count;
+}
+
+static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
+		show_min_sample_time, store_min_sample_time);
+
+static ssize_t show_above_hispeed_delay(struct kobject *kobj,
+					struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", above_hispeed_delay_val);
+}
+
+static ssize_t store_above_hispeed_delay(struct kobject *kobj,
+					 struct attribute *attr,
+					 const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	above_hispeed_delay_val = val;
+	return count;
+}
+
+define_one_global_rw(above_hispeed_delay);
+
+static ssize_t show_timer_rate(struct kobject *kobj,
+			struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", timer_rate);
+}
+
+static ssize_t store_timer_rate(struct kobject *kobj,
+			struct attribute *attr, const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+	timer_rate = val;
+	return count;
+}
+
+static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
+		show_timer_rate, store_timer_rate);
+
+static ssize_t show_boost(struct kobject *kobj, struct attribute *attr,
+			  char *buf)
+{
+	return sprintf(buf, "%d\n", boost_val);
+}
+
+static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
+			   const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	boost_val = val;
+
+	if (boost_val) {
+		trace_cpufreq_interactive_boost("on");
+		cpufreq_interactive_boost();
+	} else {
+		trace_cpufreq_interactive_unboost("off");
+	}
+
+	return count;
+}
+
+define_one_global_rw(boost);
+
+static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
+				const char *buf, size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	trace_cpufreq_interactive_boost("pulse");
+	cpufreq_interactive_boost();
+	return count;
+}
+
+static struct global_attr boostpulse =
+	__ATTR(boostpulse, 0200, NULL, store_boostpulse);
+
+static struct attribute *interactive_attributes[] = {
+	&target_load_attr.attr,
+	&hispeed_freq_attr.attr,
+	&go_hispeed_load_attr.attr,
+	&above_hispeed_delay.attr,
+	&min_sample_time_attr.attr,
+	&timer_rate_attr.attr,
+	&boost.attr,
+	&boostpulse.attr,
+	NULL,
+};
+
+static struct attribute_group interactive_attr_group = {
+	.attrs = interactive_attributes,
+	.name = "interactive",
+};
+
+static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
+					     unsigned long val,
+					     void *data)
+{
+	switch (val) {
+	case IDLE_START:
+		cpufreq_interactive_idle_start();
+		break;
+	case IDLE_END:
+		cpufreq_interactive_idle_end();
+		break;
+	}
+
+	return 0;
+}
+
+static struct notifier_block cpufreq_interactive_idle_nb = {
+	.notifier_call = cpufreq_interactive_idle_notifier,
+};
+
+static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
+		unsigned int event)
+{
+	int rc;
+	unsigned int j;
+	struct cpufreq_interactive_cpuinfo *pcpu;
+	struct cpufreq_frequency_table *freq_table;
+
+	switch (event) {
+	case CPUFREQ_GOV_START:
+		if (!cpu_online(policy->cpu))
+			return -EINVAL;
+
+		freq_table =
+			cpufreq_frequency_get_table(policy->cpu);
+		if (!hispeed_freq)
+			hispeed_freq = policy->max;
+
+		for_each_cpu(j, policy->cpus) {
+			pcpu = &per_cpu(cpuinfo, j);
+			pcpu->policy = policy;
+			pcpu->target_freq = policy->cur;
+			pcpu->freq_table = freq_table;
+			pcpu->target_set_time_in_idle =
+				get_cpu_idle_time_us(j,
+					     &pcpu->target_set_time);
+			pcpu->floor_freq = pcpu->target_freq;
+			pcpu->floor_validate_time =
+				pcpu->target_set_time;
+			pcpu->hispeed_validate_time =
+				pcpu->target_set_time;
+			pcpu->governor_enabled = 1;
+			smp_wmb();
+			pcpu->cpu_timer.expires =
+				jiffies + usecs_to_jiffies(timer_rate);
+			add_timer_on(&pcpu->cpu_timer, j);
+		}
+
+		/*
+		 * Do not register the idle hook and create sysfs
+		 * entries if we have already done so.
+		 */
+		if (atomic_inc_return(&active_count) > 1)
+			return 0;
+
+		rc = sysfs_create_group(cpufreq_global_kobject,
+				&interactive_attr_group);
+		if (rc)
+			return rc;
+
+		idle_notifier_register(&cpufreq_interactive_idle_nb);
+		break;
+
+	case CPUFREQ_GOV_STOP:
+		for_each_cpu(j, policy->cpus) {
+			pcpu = &per_cpu(cpuinfo, j);
+			pcpu->governor_enabled = 0;
+			smp_wmb();
+			del_timer_sync(&pcpu->cpu_timer);
+		}
+
+		if (atomic_dec_return(&active_count) > 0)
+			return 0;
+
+		idle_notifier_unregister(&cpufreq_interactive_idle_nb);
+		sysfs_remove_group(cpufreq_global_kobject,
+				&interactive_attr_group);
+
+		break;
+
+	case CPUFREQ_GOV_LIMITS:
+		if (policy->max < policy->cur)
+			__cpufreq_driver_target(policy,
+					policy->max, CPUFREQ_RELATION_H);
+		else if (policy->min > policy->cur)
+			__cpufreq_driver_target(policy,
+					policy->min, CPUFREQ_RELATION_L);
+		break;
+	}
+	return 0;
+}
+
+static int __init cpufreq_interactive_init(void)
+{
+	unsigned int i;
+	struct cpufreq_interactive_cpuinfo *pcpu;
+	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+
+	go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
+	min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
+	above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY;
+	timer_rate = DEFAULT_TIMER_RATE;
+
+	/* Initalize per-cpu timers */
+	for_each_possible_cpu(i) {
+		pcpu = &per_cpu(cpuinfo, i);
+		if (governidle)
+			init_timer(&pcpu->cpu_timer);
+		else
+			init_timer_deferrable(&pcpu->cpu_timer);
+		pcpu->cpu_timer.function = cpufreq_interactive_timer;
+		pcpu->cpu_timer.data = i;
+	}
+
+	spin_lock_init(&speedchange_cpumask_lock);
+	speedchange_task =
+		kthread_create(cpufreq_interactive_speedchange_task, NULL,
+			       "cfinteractive");
+	if (IS_ERR(speedchange_task))
+		return PTR_ERR(speedchange_task);
+
+	sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, &param);
+	get_task_struct(speedchange_task);
+
+	/* NB: wake up so the thread does not look hung to the freezer */
+	wake_up_process(speedchange_task);
+
+	return cpufreq_register_governor(&cpufreq_gov_interactive);
+}
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
+fs_initcall(cpufreq_interactive_init);
+#else
+module_init(cpufreq_interactive_init);
+#endif
+
+static void __exit cpufreq_interactive_exit(void)
+{
+	cpufreq_unregister_governor(&cpufreq_gov_interactive);
+	kthread_stop(speedchange_task);
+	put_task_struct(speedchange_task);
+}
+
+module_exit(cpufreq_interactive_exit);
+
+MODULE_AUTHOR("Mike Chan <mike@android.com>");
+MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
+	"Latency sensitive workloads");
+MODULE_LICENSE("GPL");