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 #include <linux/cpu.h> 30 31 #include "cpufreq_governor.h" 32 33 static struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) 34 { 35 if (have_governor_per_policy()) 36 return &policy->kobj; 37 else 38 return cpufreq_global_kobject; 39 } 40 41 static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data) 42 { 43 if (have_governor_per_policy()) 44 return dbs_data->cdata->attr_group_gov_pol; 45 else 46 return dbs_data->cdata->attr_group_gov_sys; 47 } 48 49 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) 50 { 51 u64 idle_time; 52 u64 cur_wall_time; 53 u64 busy_time; 54 55 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); 56 57 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; 58 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; 59 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; 60 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; 61 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; 62 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; 63 64 idle_time = cur_wall_time - busy_time; 65 if (wall) 66 *wall = cputime_to_usecs(cur_wall_time); 67 68 return cputime_to_usecs(idle_time); 69 } 70 71 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) 72 { 73 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL); 74 75 if (idle_time == -1ULL) 76 return get_cpu_idle_time_jiffy(cpu, wall); 77 else if (!io_busy) 78 idle_time += get_cpu_iowait_time_us(cpu, wall); 79 80 return idle_time; 81 } 82 EXPORT_SYMBOL_GPL(get_cpu_idle_time); 83 84 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu) 85 { 86 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 87 struct od_dbs_tuners *od_tuners = dbs_data->tuners; 88 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 89 struct cpufreq_policy *policy; 90 unsigned int max_load = 0; 91 unsigned int ignore_nice; 92 unsigned int j; 93 94 if (dbs_data->cdata->governor == GOV_ONDEMAND) 95 ignore_nice = od_tuners->ignore_nice; 96 else 97 ignore_nice = cs_tuners->ignore_nice; 98 99 policy = cdbs->cur_policy; 100 101 /* Get Absolute Load (in terms of freq for ondemand gov) */ 102 for_each_cpu(j, policy->cpus) { 103 struct cpu_dbs_common_info *j_cdbs; 104 u64 cur_wall_time, cur_idle_time; 105 unsigned int idle_time, wall_time; 106 unsigned int load; 107 int io_busy = 0; 108 109 j_cdbs = dbs_data->cdata->get_cpu_cdbs(j); 110 111 /* 112 * For the purpose of ondemand, waiting for disk IO is 113 * an indication that you're performance critical, and 114 * not that the system is actually idle. So do not add 115 * the iowait time to the cpu idle time. 116 */ 117 if (dbs_data->cdata->governor == GOV_ONDEMAND) 118 io_busy = od_tuners->io_is_busy; 119 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy); 120 121 wall_time = (unsigned int) 122 (cur_wall_time - j_cdbs->prev_cpu_wall); 123 j_cdbs->prev_cpu_wall = cur_wall_time; 124 125 idle_time = (unsigned int) 126 (cur_idle_time - j_cdbs->prev_cpu_idle); 127 j_cdbs->prev_cpu_idle = cur_idle_time; 128 129 if (ignore_nice) { 130 u64 cur_nice; 131 unsigned long cur_nice_jiffies; 132 133 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - 134 cdbs->prev_cpu_nice; 135 /* 136 * Assumption: nice time between sampling periods will 137 * be less than 2^32 jiffies for 32 bit sys 138 */ 139 cur_nice_jiffies = (unsigned long) 140 cputime64_to_jiffies64(cur_nice); 141 142 cdbs->prev_cpu_nice = 143 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 144 idle_time += jiffies_to_usecs(cur_nice_jiffies); 145 } 146 147 if (unlikely(!wall_time || wall_time < idle_time)) 148 continue; 149 150 load = 100 * (wall_time - idle_time) / wall_time; 151 152 if (dbs_data->cdata->governor == GOV_ONDEMAND) { 153 int freq_avg = __cpufreq_driver_getavg(policy, j); 154 if (freq_avg <= 0) 155 freq_avg = policy->cur; 156 157 load *= freq_avg; 158 } 159 160 if (load > max_load) 161 max_load = load; 162 } 163 164 dbs_data->cdata->gov_check_cpu(cpu, max_load); 165 } 166 EXPORT_SYMBOL_GPL(dbs_check_cpu); 167 168 static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data, 169 unsigned int delay) 170 { 171 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 172 173 mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay); 174 } 175 176 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, 177 unsigned int delay, bool all_cpus) 178 { 179 int i; 180 181 if (!all_cpus) { 182 __gov_queue_work(smp_processor_id(), dbs_data, delay); 183 } else { 184 get_online_cpus(); 185 for_each_cpu(i, policy->cpus) 186 __gov_queue_work(i, dbs_data, delay); 187 put_online_cpus(); 188 } 189 } 190 EXPORT_SYMBOL_GPL(gov_queue_work); 191 192 static inline void gov_cancel_work(struct dbs_data *dbs_data, 193 struct cpufreq_policy *policy) 194 { 195 struct cpu_dbs_common_info *cdbs; 196 int i; 197 198 for_each_cpu(i, policy->cpus) { 199 cdbs = dbs_data->cdata->get_cpu_cdbs(i); 200 cancel_delayed_work_sync(&cdbs->work); 201 } 202 } 203 204 /* Will return if we need to evaluate cpu load again or not */ 205 bool need_load_eval(struct cpu_dbs_common_info *cdbs, 206 unsigned int sampling_rate) 207 { 208 if (policy_is_shared(cdbs->cur_policy)) { 209 ktime_t time_now = ktime_get(); 210 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp); 211 212 /* Do nothing if we recently have sampled */ 213 if (delta_us < (s64)(sampling_rate / 2)) 214 return false; 215 else 216 cdbs->time_stamp = time_now; 217 } 218 219 return true; 220 } 221 EXPORT_SYMBOL_GPL(need_load_eval); 222 223 static void set_sampling_rate(struct dbs_data *dbs_data, 224 unsigned int sampling_rate) 225 { 226 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 227 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 228 cs_tuners->sampling_rate = sampling_rate; 229 } else { 230 struct od_dbs_tuners *od_tuners = dbs_data->tuners; 231 od_tuners->sampling_rate = sampling_rate; 232 } 233 } 234 235 int cpufreq_governor_dbs(struct cpufreq_policy *policy, 236 struct common_dbs_data *cdata, unsigned int event) 237 { 238 struct dbs_data *dbs_data; 239 struct od_cpu_dbs_info_s *od_dbs_info = NULL; 240 struct cs_cpu_dbs_info_s *cs_dbs_info = NULL; 241 struct od_ops *od_ops = NULL; 242 struct od_dbs_tuners *od_tuners = NULL; 243 struct cs_dbs_tuners *cs_tuners = NULL; 244 struct cpu_dbs_common_info *cpu_cdbs; 245 unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu; 246 int io_busy = 0; 247 int rc; 248 249 if (have_governor_per_policy()) 250 dbs_data = policy->governor_data; 251 else 252 dbs_data = cdata->gdbs_data; 253 254 WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)); 255 256 switch (event) { 257 case CPUFREQ_GOV_POLICY_INIT: 258 if (have_governor_per_policy()) { 259 WARN_ON(dbs_data); 260 } else if (dbs_data) { 261 dbs_data->usage_count++; 262 policy->governor_data = dbs_data; 263 return 0; 264 } 265 266 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL); 267 if (!dbs_data) { 268 pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__); 269 return -ENOMEM; 270 } 271 272 dbs_data->cdata = cdata; 273 dbs_data->usage_count = 1; 274 rc = cdata->init(dbs_data); 275 if (rc) { 276 pr_err("%s: POLICY_INIT: init() failed\n", __func__); 277 kfree(dbs_data); 278 return rc; 279 } 280 281 rc = sysfs_create_group(get_governor_parent_kobj(policy), 282 get_sysfs_attr(dbs_data)); 283 if (rc) { 284 cdata->exit(dbs_data); 285 kfree(dbs_data); 286 return rc; 287 } 288 289 policy->governor_data = dbs_data; 290 291 /* policy latency is in nS. Convert it to uS first */ 292 latency = policy->cpuinfo.transition_latency / 1000; 293 if (latency == 0) 294 latency = 1; 295 296 /* Bring kernel and HW constraints together */ 297 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate, 298 MIN_LATENCY_MULTIPLIER * latency); 299 set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate, 300 latency * LATENCY_MULTIPLIER)); 301 302 if ((cdata->governor == GOV_CONSERVATIVE) && 303 (!policy->governor->initialized)) { 304 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops; 305 306 cpufreq_register_notifier(cs_ops->notifier_block, 307 CPUFREQ_TRANSITION_NOTIFIER); 308 } 309 310 if (!have_governor_per_policy()) 311 cdata->gdbs_data = dbs_data; 312 313 return 0; 314 case CPUFREQ_GOV_POLICY_EXIT: 315 if (!--dbs_data->usage_count) { 316 sysfs_remove_group(get_governor_parent_kobj(policy), 317 get_sysfs_attr(dbs_data)); 318 319 if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) && 320 (policy->governor->initialized == 1)) { 321 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops; 322 323 cpufreq_unregister_notifier(cs_ops->notifier_block, 324 CPUFREQ_TRANSITION_NOTIFIER); 325 } 326 327 cdata->exit(dbs_data); 328 kfree(dbs_data); 329 cdata->gdbs_data = NULL; 330 } 331 332 policy->governor_data = NULL; 333 return 0; 334 } 335 336 cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu); 337 338 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 339 cs_tuners = dbs_data->tuners; 340 cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu); 341 sampling_rate = cs_tuners->sampling_rate; 342 ignore_nice = cs_tuners->ignore_nice; 343 } else { 344 od_tuners = dbs_data->tuners; 345 od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu); 346 sampling_rate = od_tuners->sampling_rate; 347 ignore_nice = od_tuners->ignore_nice; 348 od_ops = dbs_data->cdata->gov_ops; 349 io_busy = od_tuners->io_is_busy; 350 } 351 352 switch (event) { 353 case CPUFREQ_GOV_START: 354 if (!policy->cur) 355 return -EINVAL; 356 357 mutex_lock(&dbs_data->mutex); 358 359 for_each_cpu(j, policy->cpus) { 360 struct cpu_dbs_common_info *j_cdbs = 361 dbs_data->cdata->get_cpu_cdbs(j); 362 363 j_cdbs->cpu = j; 364 j_cdbs->cur_policy = policy; 365 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, 366 &j_cdbs->prev_cpu_wall, io_busy); 367 if (ignore_nice) 368 j_cdbs->prev_cpu_nice = 369 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 370 371 mutex_init(&j_cdbs->timer_mutex); 372 INIT_DEFERRABLE_WORK(&j_cdbs->work, 373 dbs_data->cdata->gov_dbs_timer); 374 } 375 376 /* 377 * conservative does not implement micro like ondemand 378 * governor, thus we are bound to jiffes/HZ 379 */ 380 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) { 381 cs_dbs_info->down_skip = 0; 382 cs_dbs_info->enable = 1; 383 cs_dbs_info->requested_freq = policy->cur; 384 } else { 385 od_dbs_info->rate_mult = 1; 386 od_dbs_info->sample_type = OD_NORMAL_SAMPLE; 387 od_ops->powersave_bias_init_cpu(cpu); 388 } 389 390 mutex_unlock(&dbs_data->mutex); 391 392 /* Initiate timer time stamp */ 393 cpu_cdbs->time_stamp = ktime_get(); 394 395 gov_queue_work(dbs_data, policy, 396 delay_for_sampling_rate(sampling_rate), true); 397 break; 398 399 case CPUFREQ_GOV_STOP: 400 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) 401 cs_dbs_info->enable = 0; 402 403 gov_cancel_work(dbs_data, policy); 404 405 mutex_lock(&dbs_data->mutex); 406 mutex_destroy(&cpu_cdbs->timer_mutex); 407 408 mutex_unlock(&dbs_data->mutex); 409 410 break; 411 412 case CPUFREQ_GOV_LIMITS: 413 mutex_lock(&cpu_cdbs->timer_mutex); 414 if (policy->max < cpu_cdbs->cur_policy->cur) 415 __cpufreq_driver_target(cpu_cdbs->cur_policy, 416 policy->max, CPUFREQ_RELATION_H); 417 else if (policy->min > cpu_cdbs->cur_policy->cur) 418 __cpufreq_driver_target(cpu_cdbs->cur_policy, 419 policy->min, CPUFREQ_RELATION_L); 420 dbs_check_cpu(dbs_data, cpu); 421 mutex_unlock(&cpu_cdbs->timer_mutex); 422 break; 423 } 424 return 0; 425 } 426 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs); 427