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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/cpufreq/cpufreq_ondemand.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/cpufreq/cpufreq_ondemand.c')
-rw-r--r--kernel/drivers/cpufreq/cpufreq_ondemand.c631
1 files changed, 631 insertions, 0 deletions
diff --git a/kernel/drivers/cpufreq/cpufreq_ondemand.c b/kernel/drivers/cpufreq/cpufreq_ondemand.c
new file mode 100644
index 000000000..ad3f38fd3
--- /dev/null
+++ b/kernel/drivers/cpufreq/cpufreq_ondemand.c
@@ -0,0 +1,631 @@
+/*
+ * drivers/cpufreq/cpufreq_ondemand.c
+ *
+ * Copyright (C) 2001 Russell King
+ * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
+ * Jun Nakajima <jun.nakajima@intel.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/cpu.h>
+#include <linux/percpu-defs.h>
+#include <linux/slab.h>
+#include <linux/tick.h>
+#include "cpufreq_governor.h"
+
+/* On-demand governor macros */
+#define DEF_FREQUENCY_UP_THRESHOLD (80)
+#define DEF_SAMPLING_DOWN_FACTOR (1)
+#define MAX_SAMPLING_DOWN_FACTOR (100000)
+#define MICRO_FREQUENCY_UP_THRESHOLD (95)
+#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000)
+#define MIN_FREQUENCY_UP_THRESHOLD (11)
+#define MAX_FREQUENCY_UP_THRESHOLD (100)
+
+static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
+
+static struct od_ops od_ops;
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
+static struct cpufreq_governor cpufreq_gov_ondemand;
+#endif
+
+static unsigned int default_powersave_bias;
+
+static void ondemand_powersave_bias_init_cpu(int cpu)
+{
+ struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
+
+ dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
+ dbs_info->freq_lo = 0;
+}
+
+/*
+ * Not all CPUs want IO time to be accounted as busy; this depends on how
+ * efficient idling at a higher frequency/voltage is.
+ * Pavel Machek says this is not so for various generations of AMD and old
+ * Intel systems.
+ * Mike Chan (android.com) claims this is also not true for ARM.
+ * Because of this, whitelist specific known (series) of CPUs by default, and
+ * leave all others up to the user.
+ */
+static int should_io_be_busy(void)
+{
+#if defined(CONFIG_X86)
+ /*
+ * For Intel, Core 2 (model 15) and later have an efficient idle.
+ */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+ boot_cpu_data.x86 == 6 &&
+ boot_cpu_data.x86_model >= 15)
+ return 1;
+#endif
+ return 0;
+}
+
+/*
+ * Find right freq to be set now with powersave_bias on.
+ * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
+ * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
+ */
+static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy,
+ unsigned int freq_next, unsigned int relation)
+{
+ unsigned int freq_req, freq_reduc, freq_avg;
+ unsigned int freq_hi, freq_lo;
+ unsigned int index = 0;
+ unsigned int jiffies_total, jiffies_hi, jiffies_lo;
+ struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
+ policy->cpu);
+ struct dbs_data *dbs_data = policy->governor_data;
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+
+ if (!dbs_info->freq_table) {
+ dbs_info->freq_lo = 0;
+ dbs_info->freq_lo_jiffies = 0;
+ return freq_next;
+ }
+
+ cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
+ relation, &index);
+ freq_req = dbs_info->freq_table[index].frequency;
+ freq_reduc = freq_req * od_tuners->powersave_bias / 1000;
+ freq_avg = freq_req - freq_reduc;
+
+ /* Find freq bounds for freq_avg in freq_table */
+ index = 0;
+ cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
+ CPUFREQ_RELATION_H, &index);
+ freq_lo = dbs_info->freq_table[index].frequency;
+ index = 0;
+ cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
+ CPUFREQ_RELATION_L, &index);
+ freq_hi = dbs_info->freq_table[index].frequency;
+
+ /* Find out how long we have to be in hi and lo freqs */
+ if (freq_hi == freq_lo) {
+ dbs_info->freq_lo = 0;
+ dbs_info->freq_lo_jiffies = 0;
+ return freq_lo;
+ }
+ jiffies_total = usecs_to_jiffies(od_tuners->sampling_rate);
+ jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
+ jiffies_hi += ((freq_hi - freq_lo) / 2);
+ jiffies_hi /= (freq_hi - freq_lo);
+ jiffies_lo = jiffies_total - jiffies_hi;
+ dbs_info->freq_lo = freq_lo;
+ dbs_info->freq_lo_jiffies = jiffies_lo;
+ dbs_info->freq_hi_jiffies = jiffies_hi;
+ return freq_hi;
+}
+
+static void ondemand_powersave_bias_init(void)
+{
+ int i;
+ for_each_online_cpu(i) {
+ ondemand_powersave_bias_init_cpu(i);
+ }
+}
+
+static void dbs_freq_increase(struct cpufreq_policy *policy, unsigned int freq)
+{
+ struct dbs_data *dbs_data = policy->governor_data;
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+
+ if (od_tuners->powersave_bias)
+ freq = od_ops.powersave_bias_target(policy, freq,
+ CPUFREQ_RELATION_H);
+ else if (policy->cur == policy->max)
+ return;
+
+ __cpufreq_driver_target(policy, freq, od_tuners->powersave_bias ?
+ CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
+}
+
+/*
+ * Every sampling_rate, we check, if current idle time is less than 20%
+ * (default), then we try to increase frequency. Else, we adjust the frequency
+ * proportional to load.
+ */
+static void od_check_cpu(int cpu, unsigned int load)
+{
+ struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
+ struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
+ struct dbs_data *dbs_data = policy->governor_data;
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+
+ dbs_info->freq_lo = 0;
+
+ /* Check for frequency increase */
+ if (load > od_tuners->up_threshold) {
+ /* If switching to max speed, apply sampling_down_factor */
+ if (policy->cur < policy->max)
+ dbs_info->rate_mult =
+ od_tuners->sampling_down_factor;
+ dbs_freq_increase(policy, policy->max);
+ } else {
+ /* Calculate the next frequency proportional to load */
+ unsigned int freq_next, min_f, max_f;
+
+ min_f = policy->cpuinfo.min_freq;
+ max_f = policy->cpuinfo.max_freq;
+ freq_next = min_f + load * (max_f - min_f) / 100;
+
+ /* No longer fully busy, reset rate_mult */
+ dbs_info->rate_mult = 1;
+
+ if (!od_tuners->powersave_bias) {
+ __cpufreq_driver_target(policy, freq_next,
+ CPUFREQ_RELATION_C);
+ return;
+ }
+
+ freq_next = od_ops.powersave_bias_target(policy, freq_next,
+ CPUFREQ_RELATION_L);
+ __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_C);
+ }
+}
+
+static void od_dbs_timer(struct work_struct *work)
+{
+ struct od_cpu_dbs_info_s *dbs_info =
+ container_of(work, struct od_cpu_dbs_info_s, cdbs.work.work);
+ unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
+ struct od_cpu_dbs_info_s *core_dbs_info = &per_cpu(od_cpu_dbs_info,
+ cpu);
+ struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data;
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ int delay = 0, sample_type = core_dbs_info->sample_type;
+ bool modify_all = true;
+
+ mutex_lock(&core_dbs_info->cdbs.timer_mutex);
+ if (!need_load_eval(&core_dbs_info->cdbs, od_tuners->sampling_rate)) {
+ modify_all = false;
+ goto max_delay;
+ }
+
+ /* Common NORMAL_SAMPLE setup */
+ core_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+ if (sample_type == OD_SUB_SAMPLE) {
+ delay = core_dbs_info->freq_lo_jiffies;
+ __cpufreq_driver_target(core_dbs_info->cdbs.cur_policy,
+ core_dbs_info->freq_lo, CPUFREQ_RELATION_H);
+ } else {
+ dbs_check_cpu(dbs_data, cpu);
+ if (core_dbs_info->freq_lo) {
+ /* Setup timer for SUB_SAMPLE */
+ core_dbs_info->sample_type = OD_SUB_SAMPLE;
+ delay = core_dbs_info->freq_hi_jiffies;
+ }
+ }
+
+max_delay:
+ if (!delay)
+ delay = delay_for_sampling_rate(od_tuners->sampling_rate
+ * core_dbs_info->rate_mult);
+
+ gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all);
+ mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
+}
+
+/************************** sysfs interface ************************/
+static struct common_dbs_data od_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 ondemand 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 od_dbs_tuners *od_tuners = dbs_data->tuners;
+ int cpu;
+
+ od_tuners->sampling_rate = new_rate = max(new_rate,
+ dbs_data->min_sampling_rate);
+
+ for_each_online_cpu(cpu) {
+ struct cpufreq_policy *policy;
+ struct od_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_ondemand) {
+ cpufreq_cpu_put(policy);
+ continue;
+ }
+ dbs_info = &per_cpu(od_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);
+
+ gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy,
+ usecs_to_jiffies(new_rate), true);
+
+ }
+ 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;
+}
+
+static ssize_t store_io_is_busy(struct dbs_data *dbs_data, const char *buf,
+ size_t count)
+{
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ unsigned int input;
+ int ret;
+ unsigned int j;
+
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
+ od_tuners->io_is_busy = !!input;
+
+ /* we need to re-evaluate prev_cpu_idle */
+ for_each_online_cpu(j) {
+ struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
+ j);
+ dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
+ &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
+ }
+ return count;
+}
+
+static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
+ size_t count)
+{
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ unsigned int input;
+ int ret;
+ ret = sscanf(buf, "%u", &input);
+
+ if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
+ input < MIN_FREQUENCY_UP_THRESHOLD) {
+ return -EINVAL;
+ }
+
+ od_tuners->up_threshold = input;
+ return count;
+}
+
+static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
+ const char *buf, size_t count)
+{
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ unsigned int input, j;
+ int ret;
+ ret = sscanf(buf, "%u", &input);
+
+ if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+ return -EINVAL;
+ od_tuners->sampling_down_factor = input;
+
+ /* Reset down sampling multiplier in case it was active */
+ for_each_online_cpu(j) {
+ struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
+ j);
+ dbs_info->rate_mult = 1;
+ }
+ return count;
+}
+
+static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
+ const char *buf, size_t count)
+{
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ unsigned int input;
+ int ret;
+
+ unsigned int j;
+
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
+
+ if (input > 1)
+ input = 1;
+
+ if (input == od_tuners->ignore_nice_load) { /* nothing to do */
+ return count;
+ }
+ od_tuners->ignore_nice_load = input;
+
+ /* we need to re-evaluate prev_cpu_idle */
+ for_each_online_cpu(j) {
+ struct od_cpu_dbs_info_s *dbs_info;
+ dbs_info = &per_cpu(od_cpu_dbs_info, j);
+ dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
+ &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
+ if (od_tuners->ignore_nice_load)
+ dbs_info->cdbs.prev_cpu_nice =
+ kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+
+ }
+ return count;
+}
+
+static ssize_t store_powersave_bias(struct dbs_data *dbs_data, const char *buf,
+ size_t count)
+{
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ unsigned int input;
+ int ret;
+ ret = sscanf(buf, "%u", &input);
+
+ if (ret != 1)
+ return -EINVAL;
+
+ if (input > 1000)
+ input = 1000;
+
+ od_tuners->powersave_bias = input;
+ ondemand_powersave_bias_init();
+ return count;
+}
+
+show_store_one(od, sampling_rate);
+show_store_one(od, io_is_busy);
+show_store_one(od, up_threshold);
+show_store_one(od, sampling_down_factor);
+show_store_one(od, ignore_nice_load);
+show_store_one(od, powersave_bias);
+declare_show_sampling_rate_min(od);
+
+gov_sys_pol_attr_rw(sampling_rate);
+gov_sys_pol_attr_rw(io_is_busy);
+gov_sys_pol_attr_rw(up_threshold);
+gov_sys_pol_attr_rw(sampling_down_factor);
+gov_sys_pol_attr_rw(ignore_nice_load);
+gov_sys_pol_attr_rw(powersave_bias);
+gov_sys_pol_attr_ro(sampling_rate_min);
+
+static struct attribute *dbs_attributes_gov_sys[] = {
+ &sampling_rate_min_gov_sys.attr,
+ &sampling_rate_gov_sys.attr,
+ &up_threshold_gov_sys.attr,
+ &sampling_down_factor_gov_sys.attr,
+ &ignore_nice_load_gov_sys.attr,
+ &powersave_bias_gov_sys.attr,
+ &io_is_busy_gov_sys.attr,
+ NULL
+};
+
+static struct attribute_group od_attr_group_gov_sys = {
+ .attrs = dbs_attributes_gov_sys,
+ .name = "ondemand",
+};
+
+static struct attribute *dbs_attributes_gov_pol[] = {
+ &sampling_rate_min_gov_pol.attr,
+ &sampling_rate_gov_pol.attr,
+ &up_threshold_gov_pol.attr,
+ &sampling_down_factor_gov_pol.attr,
+ &ignore_nice_load_gov_pol.attr,
+ &powersave_bias_gov_pol.attr,
+ &io_is_busy_gov_pol.attr,
+ NULL
+};
+
+static struct attribute_group od_attr_group_gov_pol = {
+ .attrs = dbs_attributes_gov_pol,
+ .name = "ondemand",
+};
+
+/************************** sysfs end ************************/
+
+static int od_init(struct dbs_data *dbs_data)
+{
+ struct od_dbs_tuners *tuners;
+ u64 idle_time;
+ int cpu;
+
+ tuners = kzalloc(sizeof(*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;
+ /*
+ * 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;
+
+ /* 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_load = 0;
+ tuners->powersave_bias = default_powersave_bias;
+ tuners->io_is_busy = should_io_be_busy();
+
+ dbs_data->tuners = tuners;
+ mutex_init(&dbs_data->mutex);
+ return 0;
+}
+
+static void od_exit(struct dbs_data *dbs_data)
+{
+ kfree(dbs_data->tuners);
+}
+
+define_get_cpu_dbs_routines(od_cpu_dbs_info);
+
+static struct od_ops od_ops = {
+ .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu,
+ .powersave_bias_target = generic_powersave_bias_target,
+ .freq_increase = dbs_freq_increase,
+};
+
+static struct common_dbs_data od_dbs_cdata = {
+ .governor = GOV_ONDEMAND,
+ .attr_group_gov_sys = &od_attr_group_gov_sys,
+ .attr_group_gov_pol = &od_attr_group_gov_pol,
+ .get_cpu_cdbs = get_cpu_cdbs,
+ .get_cpu_dbs_info_s = get_cpu_dbs_info_s,
+ .gov_dbs_timer = od_dbs_timer,
+ .gov_check_cpu = od_check_cpu,
+ .gov_ops = &od_ops,
+ .init = od_init,
+ .exit = od_exit,
+};
+
+static void od_set_powersave_bias(unsigned int powersave_bias)
+{
+ struct cpufreq_policy *policy;
+ struct dbs_data *dbs_data;
+ struct od_dbs_tuners *od_tuners;
+ unsigned int cpu;
+ cpumask_t done;
+
+ default_powersave_bias = powersave_bias;
+ cpumask_clear(&done);
+
+ get_online_cpus();
+ for_each_online_cpu(cpu) {
+ if (cpumask_test_cpu(cpu, &done))
+ continue;
+
+ policy = per_cpu(od_cpu_dbs_info, cpu).cdbs.cur_policy;
+ if (!policy)
+ continue;
+
+ cpumask_or(&done, &done, policy->cpus);
+
+ if (policy->governor != &cpufreq_gov_ondemand)
+ continue;
+
+ dbs_data = policy->governor_data;
+ od_tuners = dbs_data->tuners;
+ od_tuners->powersave_bias = default_powersave_bias;
+ }
+ put_online_cpus();
+}
+
+void od_register_powersave_bias_handler(unsigned int (*f)
+ (struct cpufreq_policy *, unsigned int, unsigned int),
+ unsigned int powersave_bias)
+{
+ od_ops.powersave_bias_target = f;
+ od_set_powersave_bias(powersave_bias);
+}
+EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler);
+
+void od_unregister_powersave_bias_handler(void)
+{
+ od_ops.powersave_bias_target = generic_powersave_bias_target;
+ od_set_powersave_bias(0);
+}
+EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler);
+
+static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy,
+ unsigned int event)
+{
+ return cpufreq_governor_dbs(policy, &od_dbs_cdata, event);
+}
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
+static
+#endif
+struct cpufreq_governor cpufreq_gov_ondemand = {
+ .name = "ondemand",
+ .governor = od_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_ondemand);
+}
+
+static void __exit cpufreq_gov_dbs_exit(void)
+{
+ cpufreq_unregister_governor(&cpufreq_gov_ondemand);
+}
+
+MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
+MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
+MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
+ "Low Latency Frequency Transition capable processors");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
+fs_initcall(cpufreq_gov_dbs_init);
+#else
+module_init(cpufreq_gov_dbs_init);
+#endif
+module_exit(cpufreq_gov_dbs_exit);