1 files changed, 851 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
new file mode 100644
index 00000000000..ddccb6723d8
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -0,0 +1,851 @@
+/*
+ * 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/mutex.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <asm/cputime.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_iowait;
+        u64 idle_exit_time;
+        u64 timer_run_time;
+        int idling;
+        u64 freq_change_time;
+        u64 freq_change_time_in_idle;
+        u64 freq_change_time_in_iowait;
+        struct cpufreq_policy *policy;
+        struct cpufreq_frequency_table *freq_table;
+        unsigned int target_freq;
+        int governor_enabled;
+};
+static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
+/* Workqueues handle frequency scaling */
+static struct task_struct *up_task;
+static struct workqueue_struct *down_wq;
+static struct work_struct freq_scale_down_work;
+static cpumask_t up_cpumask;
+static spinlock_t up_cpumask_lock;
+static cpumask_t down_cpumask;
+static spinlock_t down_cpumask_lock;
+static struct mutex set_speed_lock;
+/* Go to max speed when CPU load at or above this value. */
+#define DEFAULT_GO_MAXSPEED_LOAD 85
+static unsigned long go_maxspeed_load;
+/* Base of exponential raise to max speed; if 0 - jump to maximum */
+static unsigned long boost_factor;
+/* Max frequency boost in Hz; if 0 - no max is enforced */
+static unsigned long max_boost;
+/* Consider IO as busy */
+static unsigned long io_is_busy;
+/*
+ * Targeted sustainable load relatively to current frequency.
+ * If 0, target is set realtively to the max speed
+ */
+static unsigned long sustain_load;
+/*
+ * The minimum amount of time to spend at a frequency before we can ramp down.
+ */
+#define DEFAULT_MIN_SAMPLE_TIME 30000;
+static unsigned long min_sample_time;
+/*
+ * The sample rate of the timer used to increase frequency
+ */
+#define DEFAULT_TIMER_RATE 10000;
+static unsigned long timer_rate;
+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 unsigned int cpufreq_interactive_get_target(
+        int cpu_load, int load_since_change, struct cpufreq_policy *policy)
+{
+        unsigned int target_freq;
+        /*
+         * 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_maxspeed_load) {
+                if (!boost_factor)
+                        return policy->max;
+                target_freq = policy->cur * boost_factor;
+                if (max_boost && target_freq > policy->cur + max_boost)
+                        target_freq = policy->cur + max_boost;
+        }
+        else {
+                if (!sustain_load)
+                        return policy->max * cpu_load / 100;
+                target_freq = policy->cur * cpu_load / sustain_load;
+        }
+        target_freq = min(target_freq, policy->max);
+        return target_freq;
+}
+static inline cputime64_t get_cpu_iowait_time(
+        unsigned int cpu, cputime64_t *wall)
+{
+        u64 iowait_time = get_cpu_iowait_time_us(cpu, wall);
+        if (iowait_time == -1ULL)
+                return 0;
+        return iowait_time;
+}
+static void cpufreq_interactive_timer(unsigned long data)
+{
+        unsigned int delta_idle;
+        unsigned int delta_iowait;
+        unsigned int delta_time;
+        int cpu_load;
+        int load_since_change;
+        u64 time_in_idle;
+        u64 time_in_iowait;
+        u64 idle_exit_time;
+        struct cpufreq_interactive_cpuinfo *pcpu =
+                &per_cpu(cpuinfo, data);
+        u64 now_idle;
+        u64 now_iowait;
+        unsigned int new_freq;
+        unsigned int index;
+        unsigned long flags;
+        smp_rmb();
+        if (!pcpu->governor_enabled)
+                goto exit;
+        /*
+         * Once pcpu->timer_run_time is updated to >= pcpu->idle_exit_time,
+         * this lets idle exit know the current idle time sample has
+         * been processed, and idle exit can generate a new sample and
+         * re-arm the timer.  This prevents a concurrent idle
+         * exit on that CPU from writing a new set of info at the same time
+         * the timer function runs (the timer function can't use that info
+         * until more time passes).
+         */
+        time_in_idle = pcpu->time_in_idle;
+        time_in_iowait = pcpu->time_in_iowait;
+        idle_exit_time = pcpu->idle_exit_time;
+        now_idle = get_cpu_idle_time_us(data, &pcpu->timer_run_time);
+        now_iowait = get_cpu_iowait_time(data, NULL);
+        smp_wmb();
+        /* If we raced with cancelling a timer, skip. */
+        if (!idle_exit_time)
+                goto exit;
+        delta_idle = (unsigned int) cputime64_sub(now_idle, time_in_idle);
+        delta_iowait = (unsigned int) cputime64_sub(now_iowait, time_in_iowait);
+        delta_time = (unsigned int) cputime64_sub(pcpu->timer_run_time,
+                                                  idle_exit_time);
+        /*
+         * 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 {
+                if (io_is_busy && delta_idle >= delta_iowait)
+                        delta_idle -= delta_iowait;
+                cpu_load = 100 * (delta_time - delta_idle) / delta_time;
+        }
+        delta_idle = (unsigned int) cputime64_sub(now_idle,
+                                                pcpu->freq_change_time_in_idle);
+        delta_iowait = (unsigned int) cputime64_sub(now_iowait,
+                                        pcpu->freq_change_time_in_iowait);
+        delta_time = (unsigned int) cputime64_sub(pcpu->timer_run_time,
+                                                  pcpu->freq_change_time);
+        if ((delta_time == 0) || (delta_idle > delta_time))
+                load_since_change = 0;
+        else {
+                if (io_is_busy && delta_idle >= delta_iowait)
+                        delta_idle -= delta_iowait;
+                load_since_change =
+                        100 * (delta_time - delta_idle) / delta_time;
+        }
+        /*
+         * Combine short-term load (since last idle timer started or timer
+         * function re-armed itself) and long-term load (since last frequency
+         * change) to determine new target frequency
+         */
+        new_freq = cpufreq_interactive_get_target(cpu_load, load_since_change,
+                                                  pcpu->policy);
+        if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
+                                           new_freq, CPUFREQ_RELATION_H,
+                                           &index)) {
+                pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
+                             (int) data);
+                goto rearm;
+        }
+        new_freq = pcpu->freq_table[index].frequency;
+        if (pcpu->target_freq == new_freq)
+                goto rearm_if_notmax;
+        /*
+         * Do not scale down unless we have been at this frequency for the
+         * minimum sample time.
+         */
+        if (new_freq < pcpu->target_freq) {
+                if (cputime64_sub(pcpu->timer_run_time, pcpu->freq_change_time)
+                    < min_sample_time)
+                        goto rearm;
+        }
+        if (new_freq < pcpu->target_freq) {
+                pcpu->target_freq = new_freq;
+                spin_lock_irqsave(&down_cpumask_lock, flags);
+                cpumask_set_cpu(data, &down_cpumask);
+                spin_unlock_irqrestore(&down_cpumask_lock, flags);
+                queue_work(down_wq, &freq_scale_down_work);
+        } else {
+                pcpu->target_freq = new_freq;
+                spin_lock_irqsave(&up_cpumask_lock, flags);
+                cpumask_set_cpu(data, &up_cpumask);
+                spin_unlock_irqrestore(&up_cpumask_lock, flags);
+                wake_up_process(up_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 already at min: if that CPU is idle, don't set timer.
+                 * Else cancel the timer if that CPU goes idle.  We don't
+                 * need to re-evaluate speed until the next idle exit.
+                 */
+                if (pcpu->target_freq == pcpu->policy->min) {
+                        smp_rmb();
+                        if (pcpu->idling)
+                                goto exit;
+                        pcpu->timer_idlecancel = 1;
+                }
+                pcpu->time_in_idle = get_cpu_idle_time_us(
+                        data, &pcpu->idle_exit_time);
+                pcpu->time_in_iowait = get_cpu_iowait_time(
+                        data, NULL);
+                mod_timer(&pcpu->cpu_timer,
+                          jiffies + usecs_to_jiffies(timer_rate));
+        }
+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;
+        pcpu->idling = 1;
+        smp_wmb();
+        pending = timer_pending(&pcpu->cpu_timer);
+        if (pcpu->target_freq != pcpu->policy->min) {
+#ifdef CONFIG_SMP
+                /*
+                 * 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->time_in_idle = get_cpu_idle_time_us(
+                                smp_processor_id(), &pcpu->idle_exit_time);
+                        pcpu->time_in_iowait = get_cpu_iowait_time(
+                                smp_processor_id(), NULL);
+                        pcpu->timer_idlecancel = 0;
+                        mod_timer(&pcpu->cpu_timer,
+                                  jiffies + usecs_to_jiffies(timer_rate));
+                }
+#endif
+        } else {
+                /*
+                 * 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);
+                        /*
+                         * Ensure last timer run time is after current idle
+                         * sample start time, so next idle exit will always
+                         * start a new idle sampling period.
+                         */
+                        pcpu->idle_exit_time = 0;
+                        pcpu->timer_idlecancel = 0;
+                }
+        }
+}
+static void cpufreq_interactive_idle_end(void)
+{
+        struct cpufreq_interactive_cpuinfo *pcpu =
+                &per_cpu(cpuinfo, smp_processor_id());
+        pcpu->idling = 0;
+        smp_wmb();
+        /*
+         * Arm the timer for 1-2 ticks later if not already, and if the timer
+         * function has already processed the previous load sampling
+         * interval.  (If the timer is not pending but has not processed
+         * the previous interval, it is probably racing with us on another
+         * CPU.  Let it compute load based on the previous sample and then
+         * re-arm the timer for another interval when it's done, rather
+         * than updating the interval start time to be "now", which doesn't
+         * give the timer function enough time to make a decision on this
+         * run.)
+         */
+        if (timer_pending(&pcpu->cpu_timer) == 0 &&
+            pcpu->timer_run_time >= pcpu->idle_exit_time &&
+            pcpu->governor_enabled) {
+                pcpu->time_in_idle =
+                        get_cpu_idle_time_us(smp_processor_id(),
+                                             &pcpu->idle_exit_time);
+                pcpu->time_in_iowait =
+                        get_cpu_iowait_time(smp_processor_id(),
+                                                NULL);
+                pcpu->timer_idlecancel = 0;
+                mod_timer(&pcpu->cpu_timer,
+                          jiffies + usecs_to_jiffies(timer_rate));
+        }
+}
+static int cpufreq_interactive_up_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(&up_cpumask_lock, flags);
+                if (cpumask_empty(&up_cpumask)) {
+                        spin_unlock_irqrestore(&up_cpumask_lock, flags);
+                        schedule();
+                        if (kthread_should_stop())
+                                break;
+                        spin_lock_irqsave(&up_cpumask_lock, flags);
+                }
+                set_current_state(TASK_RUNNING);
+                tmp_mask = up_cpumask;
+                cpumask_clear(&up_cpumask);
+                spin_unlock_irqrestore(&up_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;
+                        mutex_lock(&set_speed_lock);
+                        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;
+                        }
+                        __cpufreq_driver_target(pcpu->policy,
+                                                max_freq,
+                                                CPUFREQ_RELATION_H);
+                        mutex_unlock(&set_speed_lock);
+                        pcpu->freq_change_time_in_idle =
+                                get_cpu_idle_time_us(cpu,
+                                                     &pcpu->freq_change_time);
+                        pcpu->freq_change_time_in_iowait =
+                                get_cpu_iowait_time(cpu, NULL);
+                }
+        }
+        return 0;
+}
+static void cpufreq_interactive_freq_down(struct work_struct *work)
+{
+        unsigned int cpu;
+        cpumask_t tmp_mask;
+        unsigned long flags;
+        struct cpufreq_interactive_cpuinfo *pcpu;
+        spin_lock_irqsave(&down_cpumask_lock, flags);
+        tmp_mask = down_cpumask;
+        cpumask_clear(&down_cpumask);
+        spin_unlock_irqrestore(&down_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;
+                mutex_lock(&set_speed_lock);
+                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;
+                }
+                __cpufreq_driver_target(pcpu->policy, max_freq,
+                                        CPUFREQ_RELATION_H);
+                mutex_unlock(&set_speed_lock);
+                pcpu->freq_change_time_in_idle =
+                        get_cpu_idle_time_us(cpu,
+                                             &pcpu->freq_change_time);
+                pcpu->freq_change_time_in_iowait =
+                        get_cpu_iowait_time(cpu, NULL);
+        }
+}
+static ssize_t show_go_maxspeed_load(struct kobject *kobj,
+                                     struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%lu\n", go_maxspeed_load);
+}
+static ssize_t store_go_maxspeed_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_maxspeed_load = val;
+        return count;
+}
+static struct global_attr go_maxspeed_load_attr = __ATTR(go_maxspeed_load, 0644,
+                show_go_maxspeed_load, store_go_maxspeed_load);
+static ssize_t show_boost_factor(struct kobject *kobj,
+                                     struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%lu\n", boost_factor);
+}
+static ssize_t store_boost_factor(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;
+        boost_factor = val;
+        return count;
+}
+static struct global_attr boost_factor_attr = __ATTR(boost_factor, 0644,
+                show_boost_factor, store_boost_factor);
+static ssize_t show_io_is_busy(struct kobject *kobj,
+                                     struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%lu\n", io_is_busy);
+}
+static ssize_t store_io_is_busy(struct kobject *kobj,
+                        struct attribute *attr, const char *buf, size_t count)
+{
+        if (!strict_strtoul(buf, 0, &io_is_busy))
+                return count;
+        return -EINVAL;
+}
+static struct global_attr io_is_busy_attr = __ATTR(io_is_busy, 0644,
+                show_io_is_busy, store_io_is_busy);
+static ssize_t show_max_boost(struct kobject *kobj,
+                                     struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%lu\n", max_boost);
+}
+static ssize_t store_max_boost(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;
+        max_boost = val;
+        return count;
+}
+static struct global_attr max_boost_attr = __ATTR(max_boost, 0644,
+                show_max_boost, store_max_boost);
+static ssize_t show_sustain_load(struct kobject *kobj,
+                                     struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%lu\n", sustain_load);
+}
+static ssize_t store_sustain_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;
+        sustain_load = val;
+        return count;
+}
+static struct global_attr sustain_load_attr = __ATTR(sustain_load, 0644,
+                show_sustain_load, store_sustain_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_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 struct attribute *interactive_attributes[] = {
+        &go_maxspeed_load_attr.attr,
+        &boost_factor_attr.attr,
+        &max_boost_attr.attr,
+        &io_is_busy_attr.attr,
+        &sustain_load_attr.attr,
+        &min_sample_time_attr.attr,
+        &timer_rate_attr.attr,
+        NULL,
+};
+static struct attribute_group interactive_attr_group = {
+        .attrs = interactive_attributes,
+        .name = "interactive",
+};
+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);
+                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->freq_change_time_in_idle =
+                                get_cpu_idle_time_us(j,
+                                             &pcpu->freq_change_time);
+                        pcpu->time_in_idle = pcpu->freq_change_time_in_idle;
+                        pcpu->idle_exit_time = pcpu->freq_change_time;
+                        pcpu->freq_change_time_in_iowait =
+                                get_cpu_iowait_time(j, NULL);
+                        pcpu->time_in_iowait = pcpu->freq_change_time_in_iowait;
+                        pcpu->timer_idlecancel = 1;
+                        pcpu->governor_enabled = 1;
+                        smp_wmb();
+                        if (!timer_pending(&pcpu->cpu_timer))
+                                mod_timer(&pcpu->cpu_timer, jiffies + 2);
+                }
+                /*
+                 * 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;
+                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);
+                        /*
+                         * Reset idle exit time since we may cancel the timer
+                         * before it can run after the last idle exit time,
+                         * to avoid tripping the check in idle exit for a timer
+                         * that is trying to run.
+                         */
+                        pcpu->idle_exit_time = 0;
+                }
+                flush_work(&freq_scale_down_work);
+                if (atomic_dec_return(&active_count) > 0)
+                        return 0;
+                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 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 __init cpufreq_interactive_init(void)
+{
+        unsigned int i;
+        struct cpufreq_interactive_cpuinfo *pcpu;
+        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+        go_maxspeed_load = DEFAULT_GO_MAXSPEED_LOAD;
+        min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
+        timer_rate = DEFAULT_TIMER_RATE;
+        /* Initalize per-cpu timers */
+        for_each_possible_cpu(i) {
+                pcpu = &per_cpu(cpuinfo, i);
+                init_timer(&pcpu->cpu_timer);
+                pcpu->cpu_timer.function = cpufreq_interactive_timer;
+                pcpu->cpu_timer.data = i;
+        }
+        up_task = kthread_create(cpufreq_interactive_up_task, NULL,
+                                 "kinteractiveup");
+        if (IS_ERR(up_task))
+                return PTR_ERR(up_task);
+        sched_setscheduler_nocheck(up_task, SCHED_FIFO, &param);
+        get_task_struct(up_task);
+        /* No rescuer thread, bind to CPU queuing the work for possibly
+           warm cache (probably doesn't matter much). */
+        down_wq = alloc_workqueue("knteractive_down", 0, 1);
+        if (!down_wq)
+                goto err_freeuptask;
+        INIT_WORK(&freq_scale_down_work,
+                  cpufreq_interactive_freq_down);
+        spin_lock_init(&up_cpumask_lock);
+        spin_lock_init(&down_cpumask_lock);
+        mutex_init(&set_speed_lock);
+        idle_notifier_register(&cpufreq_interactive_idle_nb);
+        return cpufreq_register_governor(&cpufreq_gov_interactive);
+err_freeuptask:
+        put_task_struct(up_task);
+        return -ENOMEM;
+}
+#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(up_task);
+        put_task_struct(up_task);
+        destroy_workqueue(down_wq);
+}
+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");