| 1 | /* |
| 2 | * drivers/cpufreq/cpufreq_conservative.c |
| 3 | * |
| 4 | * Copyright (C) 2001 Russell King |
| 5 | * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. |
| 6 | * Jun Nakajima <jun.nakajima@intel.com> |
| 7 | * (C) 2004 Alexander Clouter <alex-kernel@digriz.org.uk> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/smp.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/interrupt.h> |
| 19 | #include <linux/ctype.h> |
| 20 | #include <linux/cpufreq.h> |
| 21 | #include <linux/sysctl.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/sysfs.h> |
| 25 | #include <linux/cpu.h> |
| 26 | #include <linux/kmod.h> |
| 27 | #include <linux/workqueue.h> |
| 28 | #include <linux/jiffies.h> |
| 29 | #include <linux/kernel_stat.h> |
| 30 | #include <linux/percpu.h> |
| 31 | #include <linux/mutex.h> |
| 32 | /* |
| 33 | * dbs is used in this file as a shortform for demandbased switching |
| 34 | * It helps to keep variable names smaller, simpler |
| 35 | */ |
| 36 | |
| 37 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
| 38 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
| 39 | |
| 40 | /* |
| 41 | * The polling frequency of this governor depends on the capability of |
| 42 | * the processor. Default polling frequency is 1000 times the transition |
| 43 | * latency of the processor. The governor will work on any processor with |
| 44 | * transition latency <= 10mS, using appropriate sampling |
| 45 | * rate. |
| 46 | * For CPUs with transition latency > 10mS (mostly drivers |
| 47 | * with CPUFREQ_ETERNAL), this governor will not work. |
| 48 | * All times here are in uS. |
| 49 | */ |
| 50 | static unsigned int def_sampling_rate; |
| 51 | #define MIN_SAMPLING_RATE_RATIO (2) |
| 52 | /* for correct statistics, we need at least 10 ticks between each measure */ |
| 53 | #define MIN_STAT_SAMPLING_RATE \ |
| 54 | (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) |
| 55 | #define MIN_SAMPLING_RATE \ |
| 56 | (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) |
| 57 | /* Above MIN_SAMPLING_RATE will vanish with its sysfs file soon |
| 58 | * Define the minimal settable sampling rate to the greater of: |
| 59 | * - "HW transition latency" * 100 (same as default sampling / 10) |
| 60 | * - MIN_STAT_SAMPLING_RATE |
| 61 | * To avoid that userspace shoots itself. |
| 62 | */ |
| 63 | static unsigned int minimum_sampling_rate(void) |
| 64 | { |
| 65 | return max(def_sampling_rate / 10, MIN_STAT_SAMPLING_RATE); |
| 66 | } |
| 67 | |
| 68 | /* This will also vanish soon with removing sampling_rate_max */ |
| 69 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
| 70 | #define LATENCY_MULTIPLIER (1000) |
| 71 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
| 72 | #define MAX_SAMPLING_DOWN_FACTOR (10) |
| 73 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
| 74 | |
| 75 | static void do_dbs_timer(struct work_struct *work); |
| 76 | |
| 77 | struct cpu_dbs_info_s { |
| 78 | struct cpufreq_policy *cur_policy; |
| 79 | unsigned int prev_cpu_idle_up; |
| 80 | unsigned int prev_cpu_idle_down; |
| 81 | unsigned int enable; |
| 82 | unsigned int down_skip; |
| 83 | unsigned int requested_freq; |
| 84 | }; |
| 85 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); |
| 86 | |
| 87 | static unsigned int dbs_enable; /* number of CPUs using this policy */ |
| 88 | |
| 89 | /* |
| 90 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug |
| 91 | * lock and dbs_mutex. cpu_hotplug lock should always be held before |
| 92 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock |
| 93 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then |
| 94 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock |
| 95 | * is recursive for the same process. -Venki |
| 96 | */ |
| 97 | static DEFINE_MUTEX(dbs_mutex); |
| 98 | static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer); |
| 99 | |
| 100 | struct dbs_tuners { |
| 101 | unsigned int sampling_rate; |
| 102 | unsigned int sampling_down_factor; |
| 103 | unsigned int up_threshold; |
| 104 | unsigned int down_threshold; |
| 105 | unsigned int ignore_nice; |
| 106 | unsigned int freq_step; |
| 107 | }; |
| 108 | |
| 109 | static struct dbs_tuners dbs_tuners_ins = { |
| 110 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
| 111 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, |
| 112 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, |
| 113 | .ignore_nice = 0, |
| 114 | .freq_step = 5, |
| 115 | }; |
| 116 | |
| 117 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
| 118 | { |
| 119 | unsigned int add_nice = 0, ret; |
| 120 | |
| 121 | if (dbs_tuners_ins.ignore_nice) |
| 122 | add_nice = kstat_cpu(cpu).cpustat.nice; |
| 123 | |
| 124 | ret = kstat_cpu(cpu).cpustat.idle + |
| 125 | kstat_cpu(cpu).cpustat.iowait + |
| 126 | add_nice; |
| 127 | |
| 128 | return ret; |
| 129 | } |
| 130 | |
| 131 | /* keep track of frequency transitions */ |
| 132 | static int |
| 133 | dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
| 134 | void *data) |
| 135 | { |
| 136 | struct cpufreq_freqs *freq = data; |
| 137 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, |
| 138 | freq->cpu); |
| 139 | |
| 140 | if (!this_dbs_info->enable) |
| 141 | return 0; |
| 142 | |
| 143 | this_dbs_info->requested_freq = freq->new; |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | static struct notifier_block dbs_cpufreq_notifier_block = { |
| 149 | .notifier_call = dbs_cpufreq_notifier |
| 150 | }; |
| 151 | |
| 152 | /************************** sysfs interface ************************/ |
| 153 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) |
| 154 | { |
| 155 | static int print_once; |
| 156 | |
| 157 | if (!print_once) { |
| 158 | printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max " |
| 159 | "sysfs file is deprecated - used by: %s\n", |
| 160 | current->comm); |
| 161 | print_once = 1; |
| 162 | } |
| 163 | return sprintf(buf, "%u\n", MAX_SAMPLING_RATE); |
| 164 | } |
| 165 | |
| 166 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) |
| 167 | { |
| 168 | static int print_once; |
| 169 | |
| 170 | if (!print_once) { |
| 171 | printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max " |
| 172 | "sysfs file is deprecated - used by: %s\n", current->comm); |
| 173 | print_once = 1; |
| 174 | } |
| 175 | return sprintf(buf, "%u\n", MIN_SAMPLING_RATE); |
| 176 | } |
| 177 | |
| 178 | #define define_one_ro(_name) \ |
| 179 | static struct freq_attr _name = \ |
| 180 | __ATTR(_name, 0444, show_##_name, NULL) |
| 181 | |
| 182 | define_one_ro(sampling_rate_max); |
| 183 | define_one_ro(sampling_rate_min); |
| 184 | |
| 185 | /* cpufreq_conservative Governor Tunables */ |
| 186 | #define show_one(file_name, object) \ |
| 187 | static ssize_t show_##file_name \ |
| 188 | (struct cpufreq_policy *unused, char *buf) \ |
| 189 | { \ |
| 190 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ |
| 191 | } |
| 192 | show_one(sampling_rate, sampling_rate); |
| 193 | show_one(sampling_down_factor, sampling_down_factor); |
| 194 | show_one(up_threshold, up_threshold); |
| 195 | show_one(down_threshold, down_threshold); |
| 196 | show_one(ignore_nice_load, ignore_nice); |
| 197 | show_one(freq_step, freq_step); |
| 198 | |
| 199 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
| 200 | const char *buf, size_t count) |
| 201 | { |
| 202 | unsigned int input; |
| 203 | int ret; |
| 204 | ret = sscanf(buf, "%u", &input); |
| 205 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
| 206 | return -EINVAL; |
| 207 | |
| 208 | mutex_lock(&dbs_mutex); |
| 209 | dbs_tuners_ins.sampling_down_factor = input; |
| 210 | mutex_unlock(&dbs_mutex); |
| 211 | |
| 212 | return count; |
| 213 | } |
| 214 | |
| 215 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
| 216 | const char *buf, size_t count) |
| 217 | { |
| 218 | unsigned int input; |
| 219 | int ret; |
| 220 | ret = sscanf(buf, "%u", &input); |
| 221 | |
| 222 | mutex_lock(&dbs_mutex); |
| 223 | if (ret != 1) { |
| 224 | mutex_unlock(&dbs_mutex); |
| 225 | return -EINVAL; |
| 226 | } |
| 227 | dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate()); |
| 228 | mutex_unlock(&dbs_mutex); |
| 229 | |
| 230 | return count; |
| 231 | } |
| 232 | |
| 233 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
| 234 | const char *buf, size_t count) |
| 235 | { |
| 236 | unsigned int input; |
| 237 | int ret; |
| 238 | ret = sscanf(buf, "%u", &input); |
| 239 | |
| 240 | mutex_lock(&dbs_mutex); |
| 241 | if (ret != 1 || input > 100 || |
| 242 | input <= dbs_tuners_ins.down_threshold) { |
| 243 | mutex_unlock(&dbs_mutex); |
| 244 | return -EINVAL; |
| 245 | } |
| 246 | |
| 247 | dbs_tuners_ins.up_threshold = input; |
| 248 | mutex_unlock(&dbs_mutex); |
| 249 | |
| 250 | return count; |
| 251 | } |
| 252 | |
| 253 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, |
| 254 | const char *buf, size_t count) |
| 255 | { |
| 256 | unsigned int input; |
| 257 | int ret; |
| 258 | ret = sscanf(buf, "%u", &input); |
| 259 | |
| 260 | mutex_lock(&dbs_mutex); |
| 261 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
| 262 | mutex_unlock(&dbs_mutex); |
| 263 | return -EINVAL; |
| 264 | } |
| 265 | |
| 266 | dbs_tuners_ins.down_threshold = input; |
| 267 | mutex_unlock(&dbs_mutex); |
| 268 | |
| 269 | return count; |
| 270 | } |
| 271 | |
| 272 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
| 273 | const char *buf, size_t count) |
| 274 | { |
| 275 | unsigned int input; |
| 276 | int ret; |
| 277 | |
| 278 | unsigned int j; |
| 279 | |
| 280 | ret = sscanf(buf, "%u", &input); |
| 281 | if (ret != 1) |
| 282 | return -EINVAL; |
| 283 | |
| 284 | if (input > 1) |
| 285 | input = 1; |
| 286 | |
| 287 | mutex_lock(&dbs_mutex); |
| 288 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
| 289 | mutex_unlock(&dbs_mutex); |
| 290 | return count; |
| 291 | } |
| 292 | dbs_tuners_ins.ignore_nice = input; |
| 293 | |
| 294 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ |
| 295 | for_each_online_cpu(j) { |
| 296 | struct cpu_dbs_info_s *j_dbs_info; |
| 297 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 298 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
| 299 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
| 300 | } |
| 301 | mutex_unlock(&dbs_mutex); |
| 302 | |
| 303 | return count; |
| 304 | } |
| 305 | |
| 306 | static ssize_t store_freq_step(struct cpufreq_policy *policy, |
| 307 | const char *buf, size_t count) |
| 308 | { |
| 309 | unsigned int input; |
| 310 | int ret; |
| 311 | |
| 312 | ret = sscanf(buf, "%u", &input); |
| 313 | |
| 314 | if (ret != 1) |
| 315 | return -EINVAL; |
| 316 | |
| 317 | if (input > 100) |
| 318 | input = 100; |
| 319 | |
| 320 | /* no need to test here if freq_step is zero as the user might actually |
| 321 | * want this, they would be crazy though :) */ |
| 322 | mutex_lock(&dbs_mutex); |
| 323 | dbs_tuners_ins.freq_step = input; |
| 324 | mutex_unlock(&dbs_mutex); |
| 325 | |
| 326 | return count; |
| 327 | } |
| 328 | |
| 329 | #define define_one_rw(_name) \ |
| 330 | static struct freq_attr _name = \ |
| 331 | __ATTR(_name, 0644, show_##_name, store_##_name) |
| 332 | |
| 333 | define_one_rw(sampling_rate); |
| 334 | define_one_rw(sampling_down_factor); |
| 335 | define_one_rw(up_threshold); |
| 336 | define_one_rw(down_threshold); |
| 337 | define_one_rw(ignore_nice_load); |
| 338 | define_one_rw(freq_step); |
| 339 | |
| 340 | static struct attribute *dbs_attributes[] = { |
| 341 | &sampling_rate_max.attr, |
| 342 | &sampling_rate_min.attr, |
| 343 | &sampling_rate.attr, |
| 344 | &sampling_down_factor.attr, |
| 345 | &up_threshold.attr, |
| 346 | &down_threshold.attr, |
| 347 | &ignore_nice_load.attr, |
| 348 | &freq_step.attr, |
| 349 | NULL |
| 350 | }; |
| 351 | |
| 352 | static struct attribute_group dbs_attr_group = { |
| 353 | .attrs = dbs_attributes, |
| 354 | .name = "conservative", |
| 355 | }; |
| 356 | |
| 357 | /************************** sysfs end ************************/ |
| 358 | |
| 359 | static void dbs_check_cpu(int cpu) |
| 360 | { |
| 361 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; |
| 362 | unsigned int tmp_idle_ticks, total_idle_ticks; |
| 363 | unsigned int freq_target; |
| 364 | unsigned int freq_down_sampling_rate; |
| 365 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 366 | struct cpufreq_policy *policy; |
| 367 | |
| 368 | if (!this_dbs_info->enable) |
| 369 | return; |
| 370 | |
| 371 | policy = this_dbs_info->cur_policy; |
| 372 | |
| 373 | /* |
| 374 | * The default safe range is 20% to 80% |
| 375 | * Every sampling_rate, we check |
| 376 | * - If current idle time is less than 20%, then we try to |
| 377 | * increase frequency |
| 378 | * Every sampling_rate*sampling_down_factor, we check |
| 379 | * - If current idle time is more than 80%, then we try to |
| 380 | * decrease frequency |
| 381 | * |
| 382 | * Any frequency increase takes it to the maximum frequency. |
| 383 | * Frequency reduction happens at minimum steps of |
| 384 | * 5% (default) of max_frequency |
| 385 | */ |
| 386 | |
| 387 | /* Check for frequency increase */ |
| 388 | idle_ticks = UINT_MAX; |
| 389 | |
| 390 | /* Check for frequency increase */ |
| 391 | total_idle_ticks = get_cpu_idle_time(cpu); |
| 392 | tmp_idle_ticks = total_idle_ticks - |
| 393 | this_dbs_info->prev_cpu_idle_up; |
| 394 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; |
| 395 | |
| 396 | if (tmp_idle_ticks < idle_ticks) |
| 397 | idle_ticks = tmp_idle_ticks; |
| 398 | |
| 399 | /* Scale idle ticks by 100 and compare with up and down ticks */ |
| 400 | idle_ticks *= 100; |
| 401 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * |
| 402 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| 403 | |
| 404 | if (idle_ticks < up_idle_ticks) { |
| 405 | this_dbs_info->down_skip = 0; |
| 406 | this_dbs_info->prev_cpu_idle_down = |
| 407 | this_dbs_info->prev_cpu_idle_up; |
| 408 | |
| 409 | /* if we are already at full speed then break out early */ |
| 410 | if (this_dbs_info->requested_freq == policy->max) |
| 411 | return; |
| 412 | |
| 413 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
| 414 | |
| 415 | /* max freq cannot be less than 100. But who knows.... */ |
| 416 | if (unlikely(freq_target == 0)) |
| 417 | freq_target = 5; |
| 418 | |
| 419 | this_dbs_info->requested_freq += freq_target; |
| 420 | if (this_dbs_info->requested_freq > policy->max) |
| 421 | this_dbs_info->requested_freq = policy->max; |
| 422 | |
| 423 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
| 424 | CPUFREQ_RELATION_H); |
| 425 | return; |
| 426 | } |
| 427 | |
| 428 | /* Check for frequency decrease */ |
| 429 | this_dbs_info->down_skip++; |
| 430 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) |
| 431 | return; |
| 432 | |
| 433 | /* Check for frequency decrease */ |
| 434 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; |
| 435 | tmp_idle_ticks = total_idle_ticks - |
| 436 | this_dbs_info->prev_cpu_idle_down; |
| 437 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; |
| 438 | |
| 439 | if (tmp_idle_ticks < idle_ticks) |
| 440 | idle_ticks = tmp_idle_ticks; |
| 441 | |
| 442 | /* Scale idle ticks by 100 and compare with up and down ticks */ |
| 443 | idle_ticks *= 100; |
| 444 | this_dbs_info->down_skip = 0; |
| 445 | |
| 446 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * |
| 447 | dbs_tuners_ins.sampling_down_factor; |
| 448 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * |
| 449 | usecs_to_jiffies(freq_down_sampling_rate); |
| 450 | |
| 451 | if (idle_ticks > down_idle_ticks) { |
| 452 | /* |
| 453 | * if we are already at the lowest speed then break out early |
| 454 | * or if we 'cannot' reduce the speed as the user might want |
| 455 | * freq_target to be zero |
| 456 | */ |
| 457 | if (this_dbs_info->requested_freq == policy->min |
| 458 | || dbs_tuners_ins.freq_step == 0) |
| 459 | return; |
| 460 | |
| 461 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
| 462 | |
| 463 | /* max freq cannot be less than 100. But who knows.... */ |
| 464 | if (unlikely(freq_target == 0)) |
| 465 | freq_target = 5; |
| 466 | |
| 467 | this_dbs_info->requested_freq -= freq_target; |
| 468 | if (this_dbs_info->requested_freq < policy->min) |
| 469 | this_dbs_info->requested_freq = policy->min; |
| 470 | |
| 471 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
| 472 | CPUFREQ_RELATION_H); |
| 473 | return; |
| 474 | } |
| 475 | } |
| 476 | |
| 477 | static void do_dbs_timer(struct work_struct *work) |
| 478 | { |
| 479 | int i; |
| 480 | mutex_lock(&dbs_mutex); |
| 481 | for_each_online_cpu(i) |
| 482 | dbs_check_cpu(i); |
| 483 | schedule_delayed_work(&dbs_work, |
| 484 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
| 485 | mutex_unlock(&dbs_mutex); |
| 486 | } |
| 487 | |
| 488 | static inline void dbs_timer_init(void) |
| 489 | { |
| 490 | init_timer_deferrable(&dbs_work.timer); |
| 491 | schedule_delayed_work(&dbs_work, |
| 492 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
| 493 | return; |
| 494 | } |
| 495 | |
| 496 | static inline void dbs_timer_exit(void) |
| 497 | { |
| 498 | cancel_delayed_work(&dbs_work); |
| 499 | return; |
| 500 | } |
| 501 | |
| 502 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| 503 | unsigned int event) |
| 504 | { |
| 505 | unsigned int cpu = policy->cpu; |
| 506 | struct cpu_dbs_info_s *this_dbs_info; |
| 507 | unsigned int j; |
| 508 | int rc; |
| 509 | |
| 510 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 511 | |
| 512 | switch (event) { |
| 513 | case CPUFREQ_GOV_START: |
| 514 | if ((!cpu_online(cpu)) || (!policy->cur)) |
| 515 | return -EINVAL; |
| 516 | |
| 517 | if (this_dbs_info->enable) /* Already enabled */ |
| 518 | break; |
| 519 | |
| 520 | mutex_lock(&dbs_mutex); |
| 521 | |
| 522 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); |
| 523 | if (rc) { |
| 524 | mutex_unlock(&dbs_mutex); |
| 525 | return rc; |
| 526 | } |
| 527 | |
| 528 | for_each_cpu(j, policy->cpus) { |
| 529 | struct cpu_dbs_info_s *j_dbs_info; |
| 530 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 531 | j_dbs_info->cur_policy = policy; |
| 532 | |
| 533 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
| 534 | j_dbs_info->prev_cpu_idle_down |
| 535 | = j_dbs_info->prev_cpu_idle_up; |
| 536 | } |
| 537 | this_dbs_info->enable = 1; |
| 538 | this_dbs_info->down_skip = 0; |
| 539 | this_dbs_info->requested_freq = policy->cur; |
| 540 | |
| 541 | dbs_enable++; |
| 542 | /* |
| 543 | * Start the timerschedule work, when this governor |
| 544 | * is used for first time |
| 545 | */ |
| 546 | if (dbs_enable == 1) { |
| 547 | unsigned int latency; |
| 548 | /* policy latency is in nS. Convert it to uS first */ |
| 549 | latency = policy->cpuinfo.transition_latency / 1000; |
| 550 | if (latency == 0) |
| 551 | latency = 1; |
| 552 | |
| 553 | def_sampling_rate = |
| 554 | max(10 * latency * LATENCY_MULTIPLIER, |
| 555 | MIN_STAT_SAMPLING_RATE); |
| 556 | |
| 557 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
| 558 | |
| 559 | dbs_timer_init(); |
| 560 | cpufreq_register_notifier( |
| 561 | &dbs_cpufreq_notifier_block, |
| 562 | CPUFREQ_TRANSITION_NOTIFIER); |
| 563 | } |
| 564 | |
| 565 | mutex_unlock(&dbs_mutex); |
| 566 | break; |
| 567 | |
| 568 | case CPUFREQ_GOV_STOP: |
| 569 | mutex_lock(&dbs_mutex); |
| 570 | this_dbs_info->enable = 0; |
| 571 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
| 572 | dbs_enable--; |
| 573 | /* |
| 574 | * Stop the timerschedule work, when this governor |
| 575 | * is used for first time |
| 576 | */ |
| 577 | if (dbs_enable == 0) { |
| 578 | dbs_timer_exit(); |
| 579 | cpufreq_unregister_notifier( |
| 580 | &dbs_cpufreq_notifier_block, |
| 581 | CPUFREQ_TRANSITION_NOTIFIER); |
| 582 | } |
| 583 | |
| 584 | mutex_unlock(&dbs_mutex); |
| 585 | |
| 586 | break; |
| 587 | |
| 588 | case CPUFREQ_GOV_LIMITS: |
| 589 | mutex_lock(&dbs_mutex); |
| 590 | if (policy->max < this_dbs_info->cur_policy->cur) |
| 591 | __cpufreq_driver_target( |
| 592 | this_dbs_info->cur_policy, |
| 593 | policy->max, CPUFREQ_RELATION_H); |
| 594 | else if (policy->min > this_dbs_info->cur_policy->cur) |
| 595 | __cpufreq_driver_target( |
| 596 | this_dbs_info->cur_policy, |
| 597 | policy->min, CPUFREQ_RELATION_L); |
| 598 | mutex_unlock(&dbs_mutex); |
| 599 | break; |
| 600 | } |
| 601 | return 0; |
| 602 | } |
| 603 | |
| 604 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
| 605 | static |
| 606 | #endif |
| 607 | struct cpufreq_governor cpufreq_gov_conservative = { |
| 608 | .name = "conservative", |
| 609 | .governor = cpufreq_governor_dbs, |
| 610 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, |
| 611 | .owner = THIS_MODULE, |
| 612 | }; |
| 613 | |
| 614 | static int __init cpufreq_gov_dbs_init(void) |
| 615 | { |
| 616 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
| 617 | } |
| 618 | |
| 619 | static void __exit cpufreq_gov_dbs_exit(void) |
| 620 | { |
| 621 | /* Make sure that the scheduled work is indeed not running */ |
| 622 | flush_scheduled_work(); |
| 623 | |
| 624 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
| 625 | } |
| 626 | |
| 627 | |
| 628 | MODULE_AUTHOR("Alexander Clouter <alex-kernel@digriz.org.uk>"); |
| 629 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
| 630 | "Low Latency Frequency Transition capable processors " |
| 631 | "optimised for use in a battery environment"); |
| 632 | MODULE_LICENSE("GPL"); |
| 633 | |
| 634 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
| 635 | fs_initcall(cpufreq_gov_dbs_init); |
| 636 | #else |
| 637 | module_init(cpufreq_gov_dbs_init); |
| 638 | #endif |
| 639 | module_exit(cpufreq_gov_dbs_exit); |