| 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 <linux/export.h> |
| 20 | #include <linux/kernel_stat.h> |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/slab.h> |
| 23 | |
| 24 | #include "cpufreq_governor.h" |
| 25 | |
| 26 | static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs); |
| 27 | |
| 28 | static DEFINE_MUTEX(gov_dbs_data_mutex); |
| 29 | |
| 30 | /* Common sysfs tunables */ |
| 31 | /** |
| 32 | * store_sampling_rate - update sampling rate effective immediately if needed. |
| 33 | * |
| 34 | * If new rate is smaller than the old, simply updating |
| 35 | * dbs.sampling_rate might not be appropriate. For example, if the |
| 36 | * original sampling_rate was 1 second and the requested new sampling rate is 10 |
| 37 | * ms because the user needs immediate reaction from ondemand governor, but not |
| 38 | * sure if higher frequency will be required or not, then, the governor may |
| 39 | * change the sampling rate too late; up to 1 second later. Thus, if we are |
| 40 | * reducing the sampling rate, we need to make the new value effective |
| 41 | * immediately. |
| 42 | * |
| 43 | * This must be called with dbs_data->mutex held, otherwise traversing |
| 44 | * policy_dbs_list isn't safe. |
| 45 | */ |
| 46 | ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf, |
| 47 | size_t count) |
| 48 | { |
| 49 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| 50 | struct policy_dbs_info *policy_dbs; |
| 51 | unsigned int rate; |
| 52 | int ret; |
| 53 | ret = sscanf(buf, "%u", &rate); |
| 54 | if (ret != 1) |
| 55 | return -EINVAL; |
| 56 | |
| 57 | dbs_data->sampling_rate = max(rate, dbs_data->min_sampling_rate); |
| 58 | |
| 59 | /* |
| 60 | * We are operating under dbs_data->mutex and so the list and its |
| 61 | * entries can't be freed concurrently. |
| 62 | */ |
| 63 | list_for_each_entry(policy_dbs, &attr_set->policy_list, list) { |
| 64 | mutex_lock(&policy_dbs->timer_mutex); |
| 65 | /* |
| 66 | * On 32-bit architectures this may race with the |
| 67 | * sample_delay_ns read in dbs_update_util_handler(), but that |
| 68 | * really doesn't matter. If the read returns a value that's |
| 69 | * too big, the sample will be skipped, but the next invocation |
| 70 | * of dbs_update_util_handler() (when the update has been |
| 71 | * completed) will take a sample. |
| 72 | * |
| 73 | * If this runs in parallel with dbs_work_handler(), we may end |
| 74 | * up overwriting the sample_delay_ns value that it has just |
| 75 | * written, but it will be corrected next time a sample is |
| 76 | * taken, so it shouldn't be significant. |
| 77 | */ |
| 78 | gov_update_sample_delay(policy_dbs, 0); |
| 79 | mutex_unlock(&policy_dbs->timer_mutex); |
| 80 | } |
| 81 | |
| 82 | return count; |
| 83 | } |
| 84 | EXPORT_SYMBOL_GPL(store_sampling_rate); |
| 85 | |
| 86 | /** |
| 87 | * gov_update_cpu_data - Update CPU load data. |
| 88 | * @dbs_data: Top-level governor data pointer. |
| 89 | * |
| 90 | * Update CPU load data for all CPUs in the domain governed by @dbs_data |
| 91 | * (that may be a single policy or a bunch of them if governor tunables are |
| 92 | * system-wide). |
| 93 | * |
| 94 | * Call under the @dbs_data mutex. |
| 95 | */ |
| 96 | void gov_update_cpu_data(struct dbs_data *dbs_data) |
| 97 | { |
| 98 | struct policy_dbs_info *policy_dbs; |
| 99 | |
| 100 | list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) { |
| 101 | unsigned int j; |
| 102 | |
| 103 | for_each_cpu(j, policy_dbs->policy->cpus) { |
| 104 | struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); |
| 105 | |
| 106 | j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, |
| 107 | dbs_data->io_is_busy); |
| 108 | if (dbs_data->ignore_nice_load) |
| 109 | j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
| 110 | } |
| 111 | } |
| 112 | } |
| 113 | EXPORT_SYMBOL_GPL(gov_update_cpu_data); |
| 114 | |
| 115 | unsigned int dbs_update(struct cpufreq_policy *policy) |
| 116 | { |
| 117 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
| 118 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
| 119 | unsigned int ignore_nice = dbs_data->ignore_nice_load; |
| 120 | unsigned int max_load = 0; |
| 121 | unsigned int sampling_rate, io_busy, j; |
| 122 | |
| 123 | /* |
| 124 | * Sometimes governors may use an additional multiplier to increase |
| 125 | * sample delays temporarily. Apply that multiplier to sampling_rate |
| 126 | * so as to keep the wake-up-from-idle detection logic a bit |
| 127 | * conservative. |
| 128 | */ |
| 129 | sampling_rate = dbs_data->sampling_rate * policy_dbs->rate_mult; |
| 130 | /* |
| 131 | * For the purpose of ondemand, waiting for disk IO is an indication |
| 132 | * that you're performance critical, and not that the system is actually |
| 133 | * idle, so do not add the iowait time to the CPU idle time then. |
| 134 | */ |
| 135 | io_busy = dbs_data->io_is_busy; |
| 136 | |
| 137 | /* Get Absolute Load */ |
| 138 | for_each_cpu(j, policy->cpus) { |
| 139 | struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); |
| 140 | u64 update_time, cur_idle_time; |
| 141 | unsigned int idle_time, time_elapsed; |
| 142 | unsigned int load; |
| 143 | |
| 144 | cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy); |
| 145 | |
| 146 | time_elapsed = update_time - j_cdbs->prev_update_time; |
| 147 | j_cdbs->prev_update_time = update_time; |
| 148 | |
| 149 | idle_time = cur_idle_time - j_cdbs->prev_cpu_idle; |
| 150 | j_cdbs->prev_cpu_idle = cur_idle_time; |
| 151 | |
| 152 | if (ignore_nice) { |
| 153 | u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
| 154 | |
| 155 | idle_time += cputime_to_usecs(cur_nice - j_cdbs->prev_cpu_nice); |
| 156 | j_cdbs->prev_cpu_nice = cur_nice; |
| 157 | } |
| 158 | |
| 159 | if (unlikely(!time_elapsed)) { |
| 160 | /* |
| 161 | * That can only happen when this function is called |
| 162 | * twice in a row with a very short interval between the |
| 163 | * calls, so the previous load value can be used then. |
| 164 | */ |
| 165 | load = j_cdbs->prev_load; |
| 166 | } else if (unlikely(time_elapsed > 2 * sampling_rate && |
| 167 | j_cdbs->prev_load)) { |
| 168 | /* |
| 169 | * If the CPU had gone completely idle and a task has |
| 170 | * just woken up on this CPU now, it would be unfair to |
| 171 | * calculate 'load' the usual way for this elapsed |
| 172 | * time-window, because it would show near-zero load, |
| 173 | * irrespective of how CPU intensive that task actually |
| 174 | * was. This is undesirable for latency-sensitive bursty |
| 175 | * workloads. |
| 176 | * |
| 177 | * To avoid this, reuse the 'load' from the previous |
| 178 | * time-window and give this task a chance to start with |
| 179 | * a reasonably high CPU frequency. However, that |
| 180 | * shouldn't be over-done, lest we get stuck at a high |
| 181 | * load (high frequency) for too long, even when the |
| 182 | * current system load has actually dropped down, so |
| 183 | * clear prev_load to guarantee that the load will be |
| 184 | * computed again next time. |
| 185 | * |
| 186 | * Detecting this situation is easy: the governor's |
| 187 | * utilization update handler would not have run during |
| 188 | * CPU-idle periods. Hence, an unusually large |
| 189 | * 'time_elapsed' (as compared to the sampling rate) |
| 190 | * indicates this scenario. |
| 191 | */ |
| 192 | load = j_cdbs->prev_load; |
| 193 | j_cdbs->prev_load = 0; |
| 194 | } else { |
| 195 | if (time_elapsed >= idle_time) { |
| 196 | load = 100 * (time_elapsed - idle_time) / time_elapsed; |
| 197 | } else { |
| 198 | /* |
| 199 | * That can happen if idle_time is returned by |
| 200 | * get_cpu_idle_time_jiffy(). In that case |
| 201 | * idle_time is roughly equal to the difference |
| 202 | * between time_elapsed and "busy time" obtained |
| 203 | * from CPU statistics. Then, the "busy time" |
| 204 | * can end up being greater than time_elapsed |
| 205 | * (for example, if jiffies_64 and the CPU |
| 206 | * statistics are updated by different CPUs), |
| 207 | * so idle_time may in fact be negative. That |
| 208 | * means, though, that the CPU was busy all |
| 209 | * the time (on the rough average) during the |
| 210 | * last sampling interval and 100 can be |
| 211 | * returned as the load. |
| 212 | */ |
| 213 | load = (int)idle_time < 0 ? 100 : 0; |
| 214 | } |
| 215 | j_cdbs->prev_load = load; |
| 216 | } |
| 217 | |
| 218 | if (load > max_load) |
| 219 | max_load = load; |
| 220 | } |
| 221 | return max_load; |
| 222 | } |
| 223 | EXPORT_SYMBOL_GPL(dbs_update); |
| 224 | |
| 225 | static void dbs_work_handler(struct work_struct *work) |
| 226 | { |
| 227 | struct policy_dbs_info *policy_dbs; |
| 228 | struct cpufreq_policy *policy; |
| 229 | struct dbs_governor *gov; |
| 230 | |
| 231 | policy_dbs = container_of(work, struct policy_dbs_info, work); |
| 232 | policy = policy_dbs->policy; |
| 233 | gov = dbs_governor_of(policy); |
| 234 | |
| 235 | /* |
| 236 | * Make sure cpufreq_governor_limits() isn't evaluating load or the |
| 237 | * ondemand governor isn't updating the sampling rate in parallel. |
| 238 | */ |
| 239 | mutex_lock(&policy_dbs->timer_mutex); |
| 240 | gov_update_sample_delay(policy_dbs, gov->gov_dbs_timer(policy)); |
| 241 | mutex_unlock(&policy_dbs->timer_mutex); |
| 242 | |
| 243 | /* Allow the utilization update handler to queue up more work. */ |
| 244 | atomic_set(&policy_dbs->work_count, 0); |
| 245 | /* |
| 246 | * If the update below is reordered with respect to the sample delay |
| 247 | * modification, the utilization update handler may end up using a stale |
| 248 | * sample delay value. |
| 249 | */ |
| 250 | smp_wmb(); |
| 251 | policy_dbs->work_in_progress = false; |
| 252 | } |
| 253 | |
| 254 | static void dbs_irq_work(struct irq_work *irq_work) |
| 255 | { |
| 256 | struct policy_dbs_info *policy_dbs; |
| 257 | |
| 258 | policy_dbs = container_of(irq_work, struct policy_dbs_info, irq_work); |
| 259 | schedule_work_on(smp_processor_id(), &policy_dbs->work); |
| 260 | } |
| 261 | |
| 262 | static void dbs_update_util_handler(struct update_util_data *data, u64 time, |
| 263 | unsigned long util, unsigned long max) |
| 264 | { |
| 265 | struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util); |
| 266 | struct policy_dbs_info *policy_dbs = cdbs->policy_dbs; |
| 267 | u64 delta_ns, lst; |
| 268 | |
| 269 | /* |
| 270 | * The work may not be allowed to be queued up right now. |
| 271 | * Possible reasons: |
| 272 | * - Work has already been queued up or is in progress. |
| 273 | * - It is too early (too little time from the previous sample). |
| 274 | */ |
| 275 | if (policy_dbs->work_in_progress) |
| 276 | return; |
| 277 | |
| 278 | /* |
| 279 | * If the reads below are reordered before the check above, the value |
| 280 | * of sample_delay_ns used in the computation may be stale. |
| 281 | */ |
| 282 | smp_rmb(); |
| 283 | lst = READ_ONCE(policy_dbs->last_sample_time); |
| 284 | delta_ns = time - lst; |
| 285 | if ((s64)delta_ns < policy_dbs->sample_delay_ns) |
| 286 | return; |
| 287 | |
| 288 | /* |
| 289 | * If the policy is not shared, the irq_work may be queued up right away |
| 290 | * at this point. Otherwise, we need to ensure that only one of the |
| 291 | * CPUs sharing the policy will do that. |
| 292 | */ |
| 293 | if (policy_dbs->is_shared) { |
| 294 | if (!atomic_add_unless(&policy_dbs->work_count, 1, 1)) |
| 295 | return; |
| 296 | |
| 297 | /* |
| 298 | * If another CPU updated last_sample_time in the meantime, we |
| 299 | * shouldn't be here, so clear the work counter and bail out. |
| 300 | */ |
| 301 | if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) { |
| 302 | atomic_set(&policy_dbs->work_count, 0); |
| 303 | return; |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | policy_dbs->last_sample_time = time; |
| 308 | policy_dbs->work_in_progress = true; |
| 309 | irq_work_queue(&policy_dbs->irq_work); |
| 310 | } |
| 311 | |
| 312 | static void gov_set_update_util(struct policy_dbs_info *policy_dbs, |
| 313 | unsigned int delay_us) |
| 314 | { |
| 315 | struct cpufreq_policy *policy = policy_dbs->policy; |
| 316 | int cpu; |
| 317 | |
| 318 | gov_update_sample_delay(policy_dbs, delay_us); |
| 319 | policy_dbs->last_sample_time = 0; |
| 320 | |
| 321 | for_each_cpu(cpu, policy->cpus) { |
| 322 | struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu); |
| 323 | |
| 324 | cpufreq_add_update_util_hook(cpu, &cdbs->update_util, |
| 325 | dbs_update_util_handler); |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | static inline void gov_clear_update_util(struct cpufreq_policy *policy) |
| 330 | { |
| 331 | int i; |
| 332 | |
| 333 | for_each_cpu(i, policy->cpus) |
| 334 | cpufreq_remove_update_util_hook(i); |
| 335 | |
| 336 | synchronize_sched(); |
| 337 | } |
| 338 | |
| 339 | static void gov_cancel_work(struct cpufreq_policy *policy) |
| 340 | { |
| 341 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
| 342 | |
| 343 | gov_clear_update_util(policy_dbs->policy); |
| 344 | irq_work_sync(&policy_dbs->irq_work); |
| 345 | cancel_work_sync(&policy_dbs->work); |
| 346 | atomic_set(&policy_dbs->work_count, 0); |
| 347 | policy_dbs->work_in_progress = false; |
| 348 | } |
| 349 | |
| 350 | static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy, |
| 351 | struct dbs_governor *gov) |
| 352 | { |
| 353 | struct policy_dbs_info *policy_dbs; |
| 354 | int j; |
| 355 | |
| 356 | /* Allocate memory for per-policy governor data. */ |
| 357 | policy_dbs = gov->alloc(); |
| 358 | if (!policy_dbs) |
| 359 | return NULL; |
| 360 | |
| 361 | policy_dbs->policy = policy; |
| 362 | mutex_init(&policy_dbs->timer_mutex); |
| 363 | atomic_set(&policy_dbs->work_count, 0); |
| 364 | init_irq_work(&policy_dbs->irq_work, dbs_irq_work); |
| 365 | INIT_WORK(&policy_dbs->work, dbs_work_handler); |
| 366 | |
| 367 | /* Set policy_dbs for all CPUs, online+offline */ |
| 368 | for_each_cpu(j, policy->related_cpus) { |
| 369 | struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); |
| 370 | |
| 371 | j_cdbs->policy_dbs = policy_dbs; |
| 372 | } |
| 373 | return policy_dbs; |
| 374 | } |
| 375 | |
| 376 | static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs, |
| 377 | struct dbs_governor *gov) |
| 378 | { |
| 379 | int j; |
| 380 | |
| 381 | mutex_destroy(&policy_dbs->timer_mutex); |
| 382 | |
| 383 | for_each_cpu(j, policy_dbs->policy->related_cpus) { |
| 384 | struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); |
| 385 | |
| 386 | j_cdbs->policy_dbs = NULL; |
| 387 | j_cdbs->update_util.func = NULL; |
| 388 | } |
| 389 | gov->free(policy_dbs); |
| 390 | } |
| 391 | |
| 392 | static int cpufreq_governor_init(struct cpufreq_policy *policy) |
| 393 | { |
| 394 | struct dbs_governor *gov = dbs_governor_of(policy); |
| 395 | struct dbs_data *dbs_data; |
| 396 | struct policy_dbs_info *policy_dbs; |
| 397 | unsigned int latency; |
| 398 | int ret = 0; |
| 399 | |
| 400 | /* State should be equivalent to EXIT */ |
| 401 | if (policy->governor_data) |
| 402 | return -EBUSY; |
| 403 | |
| 404 | policy_dbs = alloc_policy_dbs_info(policy, gov); |
| 405 | if (!policy_dbs) |
| 406 | return -ENOMEM; |
| 407 | |
| 408 | /* Protect gov->gdbs_data against concurrent updates. */ |
| 409 | mutex_lock(&gov_dbs_data_mutex); |
| 410 | |
| 411 | dbs_data = gov->gdbs_data; |
| 412 | if (dbs_data) { |
| 413 | if (WARN_ON(have_governor_per_policy())) { |
| 414 | ret = -EINVAL; |
| 415 | goto free_policy_dbs_info; |
| 416 | } |
| 417 | policy_dbs->dbs_data = dbs_data; |
| 418 | policy->governor_data = policy_dbs; |
| 419 | |
| 420 | gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list); |
| 421 | goto out; |
| 422 | } |
| 423 | |
| 424 | dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL); |
| 425 | if (!dbs_data) { |
| 426 | ret = -ENOMEM; |
| 427 | goto free_policy_dbs_info; |
| 428 | } |
| 429 | |
| 430 | gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list); |
| 431 | |
| 432 | ret = gov->init(dbs_data, !policy->governor->initialized); |
| 433 | if (ret) |
| 434 | goto free_policy_dbs_info; |
| 435 | |
| 436 | /* policy latency is in ns. Convert it to us first */ |
| 437 | latency = policy->cpuinfo.transition_latency / 1000; |
| 438 | if (latency == 0) |
| 439 | latency = 1; |
| 440 | |
| 441 | /* Bring kernel and HW constraints together */ |
| 442 | dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate, |
| 443 | MIN_LATENCY_MULTIPLIER * latency); |
| 444 | dbs_data->sampling_rate = max(dbs_data->min_sampling_rate, |
| 445 | LATENCY_MULTIPLIER * latency); |
| 446 | |
| 447 | if (!have_governor_per_policy()) |
| 448 | gov->gdbs_data = dbs_data; |
| 449 | |
| 450 | policy_dbs->dbs_data = dbs_data; |
| 451 | policy->governor_data = policy_dbs; |
| 452 | |
| 453 | gov->kobj_type.sysfs_ops = &governor_sysfs_ops; |
| 454 | ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type, |
| 455 | get_governor_parent_kobj(policy), |
| 456 | "%s", gov->gov.name); |
| 457 | if (!ret) |
| 458 | goto out; |
| 459 | |
| 460 | /* Failure, so roll back. */ |
| 461 | pr_err("cpufreq: Governor initialization failed (dbs_data kobject init error %d)\n", ret); |
| 462 | |
| 463 | policy->governor_data = NULL; |
| 464 | |
| 465 | if (!have_governor_per_policy()) |
| 466 | gov->gdbs_data = NULL; |
| 467 | gov->exit(dbs_data, !policy->governor->initialized); |
| 468 | kfree(dbs_data); |
| 469 | |
| 470 | free_policy_dbs_info: |
| 471 | free_policy_dbs_info(policy_dbs, gov); |
| 472 | |
| 473 | out: |
| 474 | mutex_unlock(&gov_dbs_data_mutex); |
| 475 | return ret; |
| 476 | } |
| 477 | |
| 478 | static int cpufreq_governor_exit(struct cpufreq_policy *policy) |
| 479 | { |
| 480 | struct dbs_governor *gov = dbs_governor_of(policy); |
| 481 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
| 482 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
| 483 | unsigned int count; |
| 484 | |
| 485 | /* Protect gov->gdbs_data against concurrent updates. */ |
| 486 | mutex_lock(&gov_dbs_data_mutex); |
| 487 | |
| 488 | count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list); |
| 489 | |
| 490 | policy->governor_data = NULL; |
| 491 | |
| 492 | if (!count) { |
| 493 | if (!have_governor_per_policy()) |
| 494 | gov->gdbs_data = NULL; |
| 495 | |
| 496 | gov->exit(dbs_data, policy->governor->initialized == 1); |
| 497 | kfree(dbs_data); |
| 498 | } |
| 499 | |
| 500 | free_policy_dbs_info(policy_dbs, gov); |
| 501 | |
| 502 | mutex_unlock(&gov_dbs_data_mutex); |
| 503 | return 0; |
| 504 | } |
| 505 | |
| 506 | static int cpufreq_governor_start(struct cpufreq_policy *policy) |
| 507 | { |
| 508 | struct dbs_governor *gov = dbs_governor_of(policy); |
| 509 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
| 510 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
| 511 | unsigned int sampling_rate, ignore_nice, j; |
| 512 | unsigned int io_busy; |
| 513 | |
| 514 | if (!policy->cur) |
| 515 | return -EINVAL; |
| 516 | |
| 517 | policy_dbs->is_shared = policy_is_shared(policy); |
| 518 | policy_dbs->rate_mult = 1; |
| 519 | |
| 520 | sampling_rate = dbs_data->sampling_rate; |
| 521 | ignore_nice = dbs_data->ignore_nice_load; |
| 522 | io_busy = dbs_data->io_is_busy; |
| 523 | |
| 524 | for_each_cpu(j, policy->cpus) { |
| 525 | struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); |
| 526 | |
| 527 | j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy); |
| 528 | /* |
| 529 | * Make the first invocation of dbs_update() compute the load. |
| 530 | */ |
| 531 | j_cdbs->prev_load = 0; |
| 532 | |
| 533 | if (ignore_nice) |
| 534 | j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
| 535 | } |
| 536 | |
| 537 | gov->start(policy); |
| 538 | |
| 539 | gov_set_update_util(policy_dbs, sampling_rate); |
| 540 | return 0; |
| 541 | } |
| 542 | |
| 543 | static int cpufreq_governor_stop(struct cpufreq_policy *policy) |
| 544 | { |
| 545 | gov_cancel_work(policy); |
| 546 | return 0; |
| 547 | } |
| 548 | |
| 549 | static int cpufreq_governor_limits(struct cpufreq_policy *policy) |
| 550 | { |
| 551 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
| 552 | |
| 553 | mutex_lock(&policy_dbs->timer_mutex); |
| 554 | |
| 555 | if (policy->max < policy->cur) |
| 556 | __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H); |
| 557 | else if (policy->min > policy->cur) |
| 558 | __cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L); |
| 559 | |
| 560 | gov_update_sample_delay(policy_dbs, 0); |
| 561 | |
| 562 | mutex_unlock(&policy_dbs->timer_mutex); |
| 563 | |
| 564 | return 0; |
| 565 | } |
| 566 | |
| 567 | int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event) |
| 568 | { |
| 569 | if (event == CPUFREQ_GOV_POLICY_INIT) { |
| 570 | return cpufreq_governor_init(policy); |
| 571 | } else if (policy->governor_data) { |
| 572 | switch (event) { |
| 573 | case CPUFREQ_GOV_POLICY_EXIT: |
| 574 | return cpufreq_governor_exit(policy); |
| 575 | case CPUFREQ_GOV_START: |
| 576 | return cpufreq_governor_start(policy); |
| 577 | case CPUFREQ_GOV_STOP: |
| 578 | return cpufreq_governor_stop(policy); |
| 579 | case CPUFREQ_GOV_LIMITS: |
| 580 | return cpufreq_governor_limits(policy); |
| 581 | } |
| 582 | } |
| 583 | return -EINVAL; |
| 584 | } |
| 585 | EXPORT_SYMBOL_GPL(cpufreq_governor_dbs); |