1 /* 2 * drivers/cpufreq/cpufreq_governor.c 3 * 4 * CPUFREQ governors common code 5 * 6 * Copyright (C) 2001 Russell King 7 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. 8 * (C) 2003 Jun Nakajima <jun.nakajima@intel.com> 9 * (C) 2009 Alexander Clouter <alex@digriz.org.uk> 10 * (c) 2012 Viresh Kumar <viresh.kumar@linaro.org> 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <asm/cputime.h> 20 #include <linux/cpufreq.h> 21 #include <linux/cpumask.h> 22 #include <linux/export.h> 23 #include <linux/kernel_stat.h> 24 #include <linux/mutex.h> 25 #include <linux/slab.h> 26 #include <linux/tick.h> 27 #include <linux/types.h> 28 #include <linux/workqueue.h> 29 30 #include "cpufreq_governor.h" 31 32 static struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) 33 { 34 if (have_governor_per_policy()) 35 return &policy->kobj; 36 else 37 return cpufreq_global_kobject; 38 } 39 40 static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data) 41 { 42 if (have_governor_per_policy()) 43 return dbs_data->cdata->attr_group_gov_pol; 44 else 45 return dbs_data->cdata->attr_group_gov_sys; 46 } 47 48 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) 49 { 50 u64 idle_time; 51 u64 cur_wall_time; 52 u64 busy_time; 53 54 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); 55 56 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; 57 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; 58 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; 59 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; 60 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; 61 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 62 63 idle_time = cur_wall_time - busy_time; 64 if (wall) 65 *wall = cputime_to_usecs(cur_wall_time); 66 67 return cputime_to_usecs(idle_time); 68 } 69 70 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) 71 { 72 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); 73 74 if (idle_time == -1ULL) 75 return get_cpu_idle_time_jiffy(cpu, wall); 76 else if (!io_busy) 77 idle_time += get_cpu_iowait_time_us(cpu, wall); 78 79 return idle_time; 80 } 81 EXPORT_SYMBOL_GPL(get_cpu_idle_time); 82 83 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu) 84 { 85 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 86 struct od_dbs_tuners *od_tuners = dbs_data->tuners; 87 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 88 struct cpufreq_policy *policy; 89 unsigned int max_load = 0; 90 unsigned int ignore_nice; 91 unsigned int j; 92 93 if (dbs_data->cdata->governor == GOV_ONDEMAND) 94 ignore_nice = od_tuners->ignore_nice; 95 else 96 ignore_nice = cs_tuners->ignore_nice; 97 98 policy = cdbs->cur_policy; 99 100 /* Get Absolute Load (in terms of freq for ondemand gov) */ 101 for_each_cpu(j, policy->cpus) { 102 struct cpu_dbs_common_info *j_cdbs; 103 u64 cur_wall_time, cur_idle_time; 104 unsigned int idle_time, wall_time; 105 unsigned int load; 106 int io_busy = 0; 107 108 j_cdbs = dbs_data->cdata->get_cpu_cdbs(j); 109 110 /* 111 * For the purpose of ondemand, waiting for disk IO is 112 * an indication that you're performance critical, and 113 * not that the system is actually idle. So do not add 114 * the iowait time to the cpu idle time. 115 */ 116 if (dbs_data->cdata->governor == GOV_ONDEMAND) 117 io_busy = od_tuners->io_is_busy; 118 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy); 119 120 wall_time = (unsigned int) 121 (cur_wall_time - j_cdbs->prev_cpu_wall); 122 j_cdbs->prev_cpu_wall = cur_wall_time; 123 124 idle_time = (unsigned int) 125 (cur_idle_time - j_cdbs->prev_cpu_idle); 126 j_cdbs->prev_cpu_idle = cur_idle_time; 127 128 if (ignore_nice) { 129 u64 cur_nice; 130 unsigned long cur_nice_jiffies; 131 132 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - 133 cdbs->prev_cpu_nice; 134 /* 135 * Assumption: nice time between sampling periods will 136 * be less than 2^32 jiffies for 32 bit sys 137 */ 138 cur_nice_jiffies = (unsigned long) 139 cputime64_to_jiffies64(cur_nice); 140 141 cdbs->prev_cpu_nice = 142 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 143 idle_time += jiffies_to_usecs(cur_nice_jiffies); 144 } 145 146 if (unlikely(!wall_time || wall_time < idle_time)) 147 continue; 148 149 load = 100 * (wall_time - idle_time) / wall_time; 150 151 if (dbs_data->cdata->governor == GOV_ONDEMAND) { 152 int freq_avg = __cpufreq_driver_getavg(policy, j); 153 if (freq_avg <= 0) 154 freq_avg = policy->cur; 155 156 load *= freq_avg; 157 } 158 159 if (load > max_load) 160 max_load = load; 161 } 162 163 dbs_data->cdata->gov_check_cpu(cpu, max_load); 164 } 165 EXPORT_SYMBOL_GPL(dbs_check_cpu); 166 167 static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data, 168 unsigned int delay) 169 { 170 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 171 172 mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay); 173 } 174 175 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, 176 unsigned int delay, bool all_cpus) 177 { 178 int i; 179 180 if (!all_cpus) { 181 __gov_queue_work(smp_processor_id(), dbs_data, delay); 182 } else { 183 for_each_cpu(i, policy->cpus) 184 __gov_queue_work(i, dbs_data, delay); 185 } 186 } 187 EXPORT_SYMBOL_GPL(gov_queue_work); 188 189 static inline void gov_cancel_work(struct dbs_data *dbs_data, 190 struct cpufreq_policy *policy) 191 { 192 struct cpu_dbs_common_info *cdbs; 193 int i; 194 195 for_each_cpu(i, policy->cpus) { 196 cdbs = dbs_data->cdata->get_cpu_cdbs(i); 197 cancel_delayed_work_sync(&cdbs->work); 198 } 199 } 200 201 /* Will return if we need to evaluate cpu load again or not */ 202 bool need_load_eval(struct cpu_dbs_common_info *cdbs, 203 unsigned int sampling_rate) 204 { 205 if (policy_is_shared(cdbs->cur_policy)) { 206 ktime_t time_now = ktime_get(); 207 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp); 208 209 /* Do nothing if we recently have sampled */ 210 if (delta_us < (s64)(sampling_rate / 2)) 211 return false; 212 else 213 cdbs->time_stamp = time_now; 214 } 215 216 return true; 217 } 218 EXPORT_SYMBOL_GPL(need_load_eval); 219 220 static void set_sampling_rate(struct dbs_data *dbs_data, 221 unsigned int sampling_rate) 222 { 223 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 224 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 225 cs_tuners->sampling_rate = sampling_rate; 226 } else { 227 struct od_dbs_tuners *od_tuners = dbs_data->tuners; 228 od_tuners->sampling_rate = sampling_rate; 229 } 230 } 231 232 int cpufreq_governor_dbs(struct cpufreq_policy *policy, 233 struct common_dbs_data *cdata, unsigned int event) 234 { 235 struct dbs_data *dbs_data; 236 struct od_cpu_dbs_info_s *od_dbs_info = NULL; 237 struct cs_cpu_dbs_info_s *cs_dbs_info = NULL; 238 struct od_ops *od_ops = NULL; 239 struct od_dbs_tuners *od_tuners = NULL; 240 struct cs_dbs_tuners *cs_tuners = NULL; 241 struct cpu_dbs_common_info *cpu_cdbs; 242 unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu; 243 int io_busy = 0; 244 int rc; 245 246 if (have_governor_per_policy()) 247 dbs_data = policy->governor_data; 248 else 249 dbs_data = cdata->gdbs_data; 250 251 WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)); 252 253 switch (event) { 254 case CPUFREQ_GOV_POLICY_INIT: 255 if (have_governor_per_policy()) { 256 WARN_ON(dbs_data); 257 } else if (dbs_data) { 258 policy->governor_data = dbs_data; 259 return 0; 260 } 261 262 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL); 263 if (!dbs_data) { 264 pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__); 265 return -ENOMEM; 266 } 267 268 dbs_data->cdata = cdata; 269 rc = cdata->init(dbs_data); 270 if (rc) { 271 pr_err("%s: POLICY_INIT: init() failed\n", __func__); 272 kfree(dbs_data); 273 return rc; 274 } 275 276 rc = sysfs_create_group(get_governor_parent_kobj(policy), 277 get_sysfs_attr(dbs_data)); 278 if (rc) { 279 cdata->exit(dbs_data); 280 kfree(dbs_data); 281 return rc; 282 } 283 284 policy->governor_data = dbs_data; 285 286 /* policy latency is in nS. Convert it to uS first */ 287 latency = policy->cpuinfo.transition_latency / 1000; 288 if (latency == 0) 289 latency = 1; 290 291 /* Bring kernel and HW constraints together */ 292 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate, 293 MIN_LATENCY_MULTIPLIER * latency); 294 set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate, 295 latency * LATENCY_MULTIPLIER)); 296 297 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 298 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops; 299 300 cpufreq_register_notifier(cs_ops->notifier_block, 301 CPUFREQ_TRANSITION_NOTIFIER); 302 } 303 304 if (!have_governor_per_policy()) 305 cdata->gdbs_data = dbs_data; 306 307 return 0; 308 case CPUFREQ_GOV_POLICY_EXIT: 309 if ((policy->governor->initialized == 1) || 310 have_governor_per_policy()) { 311 sysfs_remove_group(get_governor_parent_kobj(policy), 312 get_sysfs_attr(dbs_data)); 313 314 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 315 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops; 316 317 cpufreq_unregister_notifier(cs_ops->notifier_block, 318 CPUFREQ_TRANSITION_NOTIFIER); 319 } 320 321 cdata->exit(dbs_data); 322 kfree(dbs_data); 323 cdata->gdbs_data = NULL; 324 } 325 326 policy->governor_data = NULL; 327 return 0; 328 } 329 330 cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 331 332 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 333 cs_tuners = dbs_data->tuners; 334 cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu); 335 sampling_rate = cs_tuners->sampling_rate; 336 ignore_nice = cs_tuners->ignore_nice; 337 } else { 338 od_tuners = dbs_data->tuners; 339 od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu); 340 sampling_rate = od_tuners->sampling_rate; 341 ignore_nice = od_tuners->ignore_nice; 342 od_ops = dbs_data->cdata->gov_ops; 343 io_busy = od_tuners->io_is_busy; 344 } 345 346 switch (event) { 347 case CPUFREQ_GOV_START: 348 if (!policy->cur) 349 return -EINVAL; 350 351 mutex_lock(&dbs_data->mutex); 352 353 for_each_cpu(j, policy->cpus) { 354 struct cpu_dbs_common_info *j_cdbs = 355 dbs_data->cdata->get_cpu_cdbs(j); 356 357 j_cdbs->cpu = j; 358 j_cdbs->cur_policy = policy; 359 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, 360 &j_cdbs->prev_cpu_wall, io_busy); 361 if (ignore_nice) 362 j_cdbs->prev_cpu_nice = 363 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 364 365 mutex_init(&j_cdbs->timer_mutex); 366 INIT_DEFERRABLE_WORK(&j_cdbs->work, 367 dbs_data->cdata->gov_dbs_timer); 368 } 369 370 /* 371 * conservative does not implement micro like ondemand 372 * governor, thus we are bound to jiffes/HZ 373 */ 374 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 375 cs_dbs_info->down_skip = 0; 376 cs_dbs_info->enable = 1; 377 cs_dbs_info->requested_freq = policy->cur; 378 } else { 379 od_dbs_info->rate_mult = 1; 380 od_dbs_info->sample_type = OD_NORMAL_SAMPLE; 381 od_ops->powersave_bias_init_cpu(cpu); 382 } 383 384 mutex_unlock(&dbs_data->mutex); 385 386 /* Initiate timer time stamp */ 387 cpu_cdbs->time_stamp = ktime_get(); 388 389 gov_queue_work(dbs_data, policy, 390 delay_for_sampling_rate(sampling_rate), true); 391 break; 392 393 case CPUFREQ_GOV_STOP: 394 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) 395 cs_dbs_info->enable = 0; 396 397 gov_cancel_work(dbs_data, policy); 398 399 mutex_lock(&dbs_data->mutex); 400 mutex_destroy(&cpu_cdbs->timer_mutex); 401 402 mutex_unlock(&dbs_data->mutex); 403 404 break; 405 406 case CPUFREQ_GOV_LIMITS: 407 mutex_lock(&cpu_cdbs->timer_mutex); 408 if (policy->max < cpu_cdbs->cur_policy->cur) 409 __cpufreq_driver_target(cpu_cdbs->cur_policy, 410 policy->max, CPUFREQ_RELATION_H); 411 else if (policy->min > cpu_cdbs->cur_policy->cur) 412 __cpufreq_driver_target(cpu_cdbs->cur_policy, 413 policy->min, CPUFREQ_RELATION_L); 414 dbs_check_cpu(dbs_data, cpu); 415 mutex_unlock(&cpu_cdbs->timer_mutex); 416 break; 417 } 418 return 0; 419 } 420 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs); 421