blk-cgroup.c revision a11cdaa7af56423a921a8bdad8f5a5f4ddca918a
1/* 2 * Common Block IO controller cgroup interface 3 * 4 * Based on ideas and code from CFQ, CFS and BFQ: 5 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> 6 * 7 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> 8 * Paolo Valente <paolo.valente@unimore.it> 9 * 10 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> 11 * Nauman Rafique <nauman@google.com> 12 */ 13#include <linux/ioprio.h> 14#include <linux/seq_file.h> 15#include <linux/kdev_t.h> 16#include <linux/module.h> 17#include <linux/err.h> 18#include <linux/blkdev.h> 19#include "blk-cgroup.h" 20#include <linux/genhd.h> 21 22#define MAX_KEY_LEN 100 23 24static DEFINE_SPINLOCK(blkio_list_lock); 25static LIST_HEAD(blkio_list); 26 27struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; 28EXPORT_SYMBOL_GPL(blkio_root_cgroup); 29 30static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, 31 struct cgroup *); 32static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, 33 struct task_struct *, bool); 34static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, 35 struct cgroup *, struct task_struct *, bool); 36static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); 37static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); 38 39struct cgroup_subsys blkio_subsys = { 40 .name = "blkio", 41 .create = blkiocg_create, 42 .can_attach = blkiocg_can_attach, 43 .attach = blkiocg_attach, 44 .destroy = blkiocg_destroy, 45 .populate = blkiocg_populate, 46#ifdef CONFIG_BLK_CGROUP 47 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ 48 .subsys_id = blkio_subsys_id, 49#endif 50 .use_id = 1, 51 .module = THIS_MODULE, 52}; 53EXPORT_SYMBOL_GPL(blkio_subsys); 54 55static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg, 56 struct blkio_policy_node *pn) 57{ 58 list_add(&pn->node, &blkcg->policy_list); 59} 60 61/* Must be called with blkcg->lock held */ 62static inline void blkio_policy_delete_node(struct blkio_policy_node *pn) 63{ 64 list_del(&pn->node); 65} 66 67/* Must be called with blkcg->lock held */ 68static struct blkio_policy_node * 69blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev) 70{ 71 struct blkio_policy_node *pn; 72 73 list_for_each_entry(pn, &blkcg->policy_list, node) { 74 if (pn->dev == dev) 75 return pn; 76 } 77 78 return NULL; 79} 80 81struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) 82{ 83 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), 84 struct blkio_cgroup, css); 85} 86EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); 87 88void blkio_group_init(struct blkio_group *blkg) 89{ 90 spin_lock_init(&blkg->stats_lock); 91} 92EXPORT_SYMBOL_GPL(blkio_group_init); 93 94/* 95 * Add to the appropriate stat variable depending on the request type. 96 * This should be called with the blkg->stats_lock held. 97 */ 98static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, 99 bool sync) 100{ 101 if (direction) 102 stat[BLKIO_STAT_WRITE] += add; 103 else 104 stat[BLKIO_STAT_READ] += add; 105 if (sync) 106 stat[BLKIO_STAT_SYNC] += add; 107 else 108 stat[BLKIO_STAT_ASYNC] += add; 109} 110 111/* 112 * Decrements the appropriate stat variable if non-zero depending on the 113 * request type. Panics on value being zero. 114 * This should be called with the blkg->stats_lock held. 115 */ 116static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync) 117{ 118 if (direction) { 119 BUG_ON(stat[BLKIO_STAT_WRITE] == 0); 120 stat[BLKIO_STAT_WRITE]--; 121 } else { 122 BUG_ON(stat[BLKIO_STAT_READ] == 0); 123 stat[BLKIO_STAT_READ]--; 124 } 125 if (sync) { 126 BUG_ON(stat[BLKIO_STAT_SYNC] == 0); 127 stat[BLKIO_STAT_SYNC]--; 128 } else { 129 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0); 130 stat[BLKIO_STAT_ASYNC]--; 131 } 132} 133 134#ifdef CONFIG_DEBUG_BLK_CGROUP 135/* This should be called with the blkg->stats_lock held. */ 136static void blkio_set_start_group_wait_time(struct blkio_group *blkg, 137 struct blkio_group *curr_blkg) 138{ 139 if (blkio_blkg_waiting(&blkg->stats)) 140 return; 141 if (blkg == curr_blkg) 142 return; 143 blkg->stats.start_group_wait_time = sched_clock(); 144 blkio_mark_blkg_waiting(&blkg->stats); 145} 146 147/* This should be called with the blkg->stats_lock held. */ 148static void blkio_update_group_wait_time(struct blkio_group_stats *stats) 149{ 150 unsigned long long now; 151 152 if (!blkio_blkg_waiting(stats)) 153 return; 154 155 now = sched_clock(); 156 if (time_after64(now, stats->start_group_wait_time)) 157 stats->group_wait_time += now - stats->start_group_wait_time; 158 blkio_clear_blkg_waiting(stats); 159} 160 161/* This should be called with the blkg->stats_lock held. */ 162static void blkio_end_empty_time(struct blkio_group_stats *stats) 163{ 164 unsigned long long now; 165 166 if (!blkio_blkg_empty(stats)) 167 return; 168 169 now = sched_clock(); 170 if (time_after64(now, stats->start_empty_time)) 171 stats->empty_time += now - stats->start_empty_time; 172 blkio_clear_blkg_empty(stats); 173} 174 175void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) 176{ 177 unsigned long flags; 178 179 spin_lock_irqsave(&blkg->stats_lock, flags); 180 BUG_ON(blkio_blkg_idling(&blkg->stats)); 181 blkg->stats.start_idle_time = sched_clock(); 182 blkio_mark_blkg_idling(&blkg->stats); 183 spin_unlock_irqrestore(&blkg->stats_lock, flags); 184} 185EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats); 186 187void blkiocg_update_idle_time_stats(struct blkio_group *blkg) 188{ 189 unsigned long flags; 190 unsigned long long now; 191 struct blkio_group_stats *stats; 192 193 spin_lock_irqsave(&blkg->stats_lock, flags); 194 stats = &blkg->stats; 195 if (blkio_blkg_idling(stats)) { 196 now = sched_clock(); 197 if (time_after64(now, stats->start_idle_time)) 198 stats->idle_time += now - stats->start_idle_time; 199 blkio_clear_blkg_idling(stats); 200 } 201 spin_unlock_irqrestore(&blkg->stats_lock, flags); 202} 203EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats); 204 205void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) 206{ 207 unsigned long flags; 208 struct blkio_group_stats *stats; 209 210 spin_lock_irqsave(&blkg->stats_lock, flags); 211 stats = &blkg->stats; 212 stats->avg_queue_size_sum += 213 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] + 214 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]; 215 stats->avg_queue_size_samples++; 216 blkio_update_group_wait_time(stats); 217 spin_unlock_irqrestore(&blkg->stats_lock, flags); 218} 219EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats); 220 221void blkiocg_update_dequeue_stats(struct blkio_group *blkg, 222 unsigned long dequeue) 223{ 224 blkg->stats.dequeue += dequeue; 225} 226EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); 227#else 228static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg, 229 struct blkio_group *curr_blkg) {} 230static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {} 231#endif 232 233void blkiocg_update_io_add_stats(struct blkio_group *blkg, 234 struct blkio_group *curr_blkg, bool direction, 235 bool sync) 236{ 237 unsigned long flags; 238 239 spin_lock_irqsave(&blkg->stats_lock, flags); 240 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction, 241 sync); 242 blkio_end_empty_time(&blkg->stats); 243 blkio_set_start_group_wait_time(blkg, curr_blkg); 244 spin_unlock_irqrestore(&blkg->stats_lock, flags); 245} 246EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats); 247 248void blkiocg_update_io_remove_stats(struct blkio_group *blkg, 249 bool direction, bool sync) 250{ 251 unsigned long flags; 252 253 spin_lock_irqsave(&blkg->stats_lock, flags); 254 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 255 direction, sync); 256 spin_unlock_irqrestore(&blkg->stats_lock, flags); 257} 258EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats); 259 260void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) 261{ 262 unsigned long flags; 263 264 spin_lock_irqsave(&blkg->stats_lock, flags); 265 blkg->stats.time += time; 266 spin_unlock_irqrestore(&blkg->stats_lock, flags); 267} 268EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); 269 270void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore) 271{ 272 unsigned long flags; 273 struct blkio_group_stats *stats; 274 275 spin_lock_irqsave(&blkg->stats_lock, flags); 276 stats = &blkg->stats; 277 278 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] || 279 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) { 280 spin_unlock_irqrestore(&blkg->stats_lock, flags); 281 return; 282 } 283 284 /* 285 * If ignore is set, we do not panic on the empty flag being set 286 * already. This is to avoid cases where there are superfluous timeslice 287 * complete events (for eg., forced_dispatch in CFQ) when no IOs are 288 * served which could result in triggering the empty check incorrectly. 289 */ 290 BUG_ON(!ignore && blkio_blkg_empty(stats)); 291 stats->start_empty_time = sched_clock(); 292 blkio_mark_blkg_empty(stats); 293 spin_unlock_irqrestore(&blkg->stats_lock, flags); 294} 295EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time); 296 297void blkiocg_update_dispatch_stats(struct blkio_group *blkg, 298 uint64_t bytes, bool direction, bool sync) 299{ 300 struct blkio_group_stats *stats; 301 unsigned long flags; 302 303 spin_lock_irqsave(&blkg->stats_lock, flags); 304 stats = &blkg->stats; 305 stats->sectors += bytes >> 9; 306 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction, 307 sync); 308 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes, 309 direction, sync); 310 spin_unlock_irqrestore(&blkg->stats_lock, flags); 311} 312EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); 313 314void blkiocg_update_completion_stats(struct blkio_group *blkg, 315 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) 316{ 317 struct blkio_group_stats *stats; 318 unsigned long flags; 319 unsigned long long now = sched_clock(); 320 321 spin_lock_irqsave(&blkg->stats_lock, flags); 322 stats = &blkg->stats; 323 if (time_after64(now, io_start_time)) 324 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], 325 now - io_start_time, direction, sync); 326 if (time_after64(io_start_time, start_time)) 327 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], 328 io_start_time - start_time, direction, sync); 329 spin_unlock_irqrestore(&blkg->stats_lock, flags); 330} 331EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); 332 333void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, 334 bool sync) 335{ 336 unsigned long flags; 337 338 spin_lock_irqsave(&blkg->stats_lock, flags); 339 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, 340 sync); 341 spin_unlock_irqrestore(&blkg->stats_lock, flags); 342} 343EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); 344 345void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, 346 struct blkio_group *blkg, void *key, dev_t dev) 347{ 348 unsigned long flags; 349 350 spin_lock_irqsave(&blkcg->lock, flags); 351 rcu_assign_pointer(blkg->key, key); 352 blkg->blkcg_id = css_id(&blkcg->css); 353 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); 354 spin_unlock_irqrestore(&blkcg->lock, flags); 355#ifdef CONFIG_DEBUG_BLK_CGROUP 356 /* Need to take css reference ? */ 357 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); 358#endif 359 blkg->dev = dev; 360} 361EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); 362 363static void __blkiocg_del_blkio_group(struct blkio_group *blkg) 364{ 365 hlist_del_init_rcu(&blkg->blkcg_node); 366 blkg->blkcg_id = 0; 367} 368 369/* 370 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 371 * indicating that blk_group was unhashed by the time we got to it. 372 */ 373int blkiocg_del_blkio_group(struct blkio_group *blkg) 374{ 375 struct blkio_cgroup *blkcg; 376 unsigned long flags; 377 struct cgroup_subsys_state *css; 378 int ret = 1; 379 380 rcu_read_lock(); 381 css = css_lookup(&blkio_subsys, blkg->blkcg_id); 382 if (!css) 383 goto out; 384 385 blkcg = container_of(css, struct blkio_cgroup, css); 386 spin_lock_irqsave(&blkcg->lock, flags); 387 if (!hlist_unhashed(&blkg->blkcg_node)) { 388 __blkiocg_del_blkio_group(blkg); 389 ret = 0; 390 } 391 spin_unlock_irqrestore(&blkcg->lock, flags); 392out: 393 rcu_read_unlock(); 394 return ret; 395} 396EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); 397 398/* called under rcu_read_lock(). */ 399struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) 400{ 401 struct blkio_group *blkg; 402 struct hlist_node *n; 403 void *__key; 404 405 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { 406 __key = blkg->key; 407 if (__key == key) 408 return blkg; 409 } 410 411 return NULL; 412} 413EXPORT_SYMBOL_GPL(blkiocg_lookup_group); 414 415#define SHOW_FUNCTION(__VAR) \ 416static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ 417 struct cftype *cftype) \ 418{ \ 419 struct blkio_cgroup *blkcg; \ 420 \ 421 blkcg = cgroup_to_blkio_cgroup(cgroup); \ 422 return (u64)blkcg->__VAR; \ 423} 424 425SHOW_FUNCTION(weight); 426#undef SHOW_FUNCTION 427 428static int 429blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) 430{ 431 struct blkio_cgroup *blkcg; 432 struct blkio_group *blkg; 433 struct hlist_node *n; 434 struct blkio_policy_type *blkiop; 435 struct blkio_policy_node *pn; 436 437 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) 438 return -EINVAL; 439 440 blkcg = cgroup_to_blkio_cgroup(cgroup); 441 spin_lock(&blkio_list_lock); 442 spin_lock_irq(&blkcg->lock); 443 blkcg->weight = (unsigned int)val; 444 445 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 446 pn = blkio_policy_search_node(blkcg, blkg->dev); 447 448 if (pn) 449 continue; 450 451 list_for_each_entry(blkiop, &blkio_list, list) 452 blkiop->ops.blkio_update_group_weight_fn(blkg, 453 blkcg->weight); 454 } 455 spin_unlock_irq(&blkcg->lock); 456 spin_unlock(&blkio_list_lock); 457 return 0; 458} 459 460static int 461blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) 462{ 463 struct blkio_cgroup *blkcg; 464 struct blkio_group *blkg; 465 struct blkio_group_stats *stats; 466 struct hlist_node *n; 467 uint64_t queued[BLKIO_STAT_TOTAL]; 468 int i; 469#ifdef CONFIG_DEBUG_BLK_CGROUP 470 bool idling, waiting, empty; 471 unsigned long long now = sched_clock(); 472#endif 473 474 blkcg = cgroup_to_blkio_cgroup(cgroup); 475 spin_lock_irq(&blkcg->lock); 476 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 477 spin_lock(&blkg->stats_lock); 478 stats = &blkg->stats; 479#ifdef CONFIG_DEBUG_BLK_CGROUP 480 idling = blkio_blkg_idling(stats); 481 waiting = blkio_blkg_waiting(stats); 482 empty = blkio_blkg_empty(stats); 483#endif 484 for (i = 0; i < BLKIO_STAT_TOTAL; i++) 485 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; 486 memset(stats, 0, sizeof(struct blkio_group_stats)); 487 for (i = 0; i < BLKIO_STAT_TOTAL; i++) 488 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; 489#ifdef CONFIG_DEBUG_BLK_CGROUP 490 if (idling) { 491 blkio_mark_blkg_idling(stats); 492 stats->start_idle_time = now; 493 } 494 if (waiting) { 495 blkio_mark_blkg_waiting(stats); 496 stats->start_group_wait_time = now; 497 } 498 if (empty) { 499 blkio_mark_blkg_empty(stats); 500 stats->start_empty_time = now; 501 } 502#endif 503 spin_unlock(&blkg->stats_lock); 504 } 505 spin_unlock_irq(&blkcg->lock); 506 return 0; 507} 508 509static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, 510 int chars_left, bool diskname_only) 511{ 512 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); 513 chars_left -= strlen(str); 514 if (chars_left <= 0) { 515 printk(KERN_WARNING 516 "Possibly incorrect cgroup stat display format"); 517 return; 518 } 519 if (diskname_only) 520 return; 521 switch (type) { 522 case BLKIO_STAT_READ: 523 strlcat(str, " Read", chars_left); 524 break; 525 case BLKIO_STAT_WRITE: 526 strlcat(str, " Write", chars_left); 527 break; 528 case BLKIO_STAT_SYNC: 529 strlcat(str, " Sync", chars_left); 530 break; 531 case BLKIO_STAT_ASYNC: 532 strlcat(str, " Async", chars_left); 533 break; 534 case BLKIO_STAT_TOTAL: 535 strlcat(str, " Total", chars_left); 536 break; 537 default: 538 strlcat(str, " Invalid", chars_left); 539 } 540} 541 542static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, 543 struct cgroup_map_cb *cb, dev_t dev) 544{ 545 blkio_get_key_name(0, dev, str, chars_left, true); 546 cb->fill(cb, str, val); 547 return val; 548} 549 550/* This should be called with blkg->stats_lock held */ 551static uint64_t blkio_get_stat(struct blkio_group *blkg, 552 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) 553{ 554 uint64_t disk_total; 555 char key_str[MAX_KEY_LEN]; 556 enum stat_sub_type sub_type; 557 558 if (type == BLKIO_STAT_TIME) 559 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 560 blkg->stats.time, cb, dev); 561 if (type == BLKIO_STAT_SECTORS) 562 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 563 blkg->stats.sectors, cb, dev); 564#ifdef CONFIG_DEBUG_BLK_CGROUP 565 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { 566 uint64_t sum = blkg->stats.avg_queue_size_sum; 567 uint64_t samples = blkg->stats.avg_queue_size_samples; 568 if (samples) 569 do_div(sum, samples); 570 else 571 sum = 0; 572 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); 573 } 574 if (type == BLKIO_STAT_GROUP_WAIT_TIME) 575 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 576 blkg->stats.group_wait_time, cb, dev); 577 if (type == BLKIO_STAT_IDLE_TIME) 578 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 579 blkg->stats.idle_time, cb, dev); 580 if (type == BLKIO_STAT_EMPTY_TIME) 581 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 582 blkg->stats.empty_time, cb, dev); 583 if (type == BLKIO_STAT_DEQUEUE) 584 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 585 blkg->stats.dequeue, cb, dev); 586#endif 587 588 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; 589 sub_type++) { 590 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); 591 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); 592 } 593 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + 594 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; 595 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); 596 cb->fill(cb, key_str, disk_total); 597 return disk_total; 598} 599 600#define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ 601static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ 602 struct cftype *cftype, struct cgroup_map_cb *cb) \ 603{ \ 604 struct blkio_cgroup *blkcg; \ 605 struct blkio_group *blkg; \ 606 struct hlist_node *n; \ 607 uint64_t cgroup_total = 0; \ 608 \ 609 if (!cgroup_lock_live_group(cgroup)) \ 610 return -ENODEV; \ 611 \ 612 blkcg = cgroup_to_blkio_cgroup(cgroup); \ 613 rcu_read_lock(); \ 614 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ 615 if (blkg->dev) { \ 616 spin_lock_irq(&blkg->stats_lock); \ 617 cgroup_total += blkio_get_stat(blkg, cb, \ 618 blkg->dev, type); \ 619 spin_unlock_irq(&blkg->stats_lock); \ 620 } \ 621 } \ 622 if (show_total) \ 623 cb->fill(cb, "Total", cgroup_total); \ 624 rcu_read_unlock(); \ 625 cgroup_unlock(); \ 626 return 0; \ 627} 628 629SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); 630SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); 631SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); 632SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); 633SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); 634SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); 635SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); 636SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1); 637#ifdef CONFIG_DEBUG_BLK_CGROUP 638SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); 639SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0); 640SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0); 641SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0); 642SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0); 643#endif 644#undef SHOW_FUNCTION_PER_GROUP 645 646static int blkio_check_dev_num(dev_t dev) 647{ 648 int part = 0; 649 struct gendisk *disk; 650 651 disk = get_gendisk(dev, &part); 652 if (!disk || part) 653 return -ENODEV; 654 655 return 0; 656} 657 658static int blkio_policy_parse_and_set(char *buf, 659 struct blkio_policy_node *newpn) 660{ 661 char *s[4], *p, *major_s = NULL, *minor_s = NULL; 662 int ret; 663 unsigned long major, minor, temp; 664 int i = 0; 665 dev_t dev; 666 667 memset(s, 0, sizeof(s)); 668 669 while ((p = strsep(&buf, " ")) != NULL) { 670 if (!*p) 671 continue; 672 673 s[i++] = p; 674 675 /* Prevent from inputing too many things */ 676 if (i == 3) 677 break; 678 } 679 680 if (i != 2) 681 return -EINVAL; 682 683 p = strsep(&s[0], ":"); 684 if (p != NULL) 685 major_s = p; 686 else 687 return -EINVAL; 688 689 minor_s = s[0]; 690 if (!minor_s) 691 return -EINVAL; 692 693 ret = strict_strtoul(major_s, 10, &major); 694 if (ret) 695 return -EINVAL; 696 697 ret = strict_strtoul(minor_s, 10, &minor); 698 if (ret) 699 return -EINVAL; 700 701 dev = MKDEV(major, minor); 702 703 ret = blkio_check_dev_num(dev); 704 if (ret) 705 return ret; 706 707 newpn->dev = dev; 708 709 if (s[1] == NULL) 710 return -EINVAL; 711 712 ret = strict_strtoul(s[1], 10, &temp); 713 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || 714 temp > BLKIO_WEIGHT_MAX) 715 return -EINVAL; 716 717 newpn->weight = temp; 718 719 return 0; 720} 721 722unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, 723 dev_t dev) 724{ 725 struct blkio_policy_node *pn; 726 727 pn = blkio_policy_search_node(blkcg, dev); 728 if (pn) 729 return pn->weight; 730 else 731 return blkcg->weight; 732} 733EXPORT_SYMBOL_GPL(blkcg_get_weight); 734 735 736static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft, 737 const char *buffer) 738{ 739 int ret = 0; 740 char *buf; 741 struct blkio_policy_node *newpn, *pn; 742 struct blkio_cgroup *blkcg; 743 struct blkio_group *blkg; 744 int keep_newpn = 0; 745 struct hlist_node *n; 746 struct blkio_policy_type *blkiop; 747 748 buf = kstrdup(buffer, GFP_KERNEL); 749 if (!buf) 750 return -ENOMEM; 751 752 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL); 753 if (!newpn) { 754 ret = -ENOMEM; 755 goto free_buf; 756 } 757 758 ret = blkio_policy_parse_and_set(buf, newpn); 759 if (ret) 760 goto free_newpn; 761 762 blkcg = cgroup_to_blkio_cgroup(cgrp); 763 764 spin_lock_irq(&blkcg->lock); 765 766 pn = blkio_policy_search_node(blkcg, newpn->dev); 767 if (!pn) { 768 if (newpn->weight != 0) { 769 blkio_policy_insert_node(blkcg, newpn); 770 keep_newpn = 1; 771 } 772 spin_unlock_irq(&blkcg->lock); 773 goto update_io_group; 774 } 775 776 if (newpn->weight == 0) { 777 /* weight == 0 means deleteing a specific weight */ 778 blkio_policy_delete_node(pn); 779 spin_unlock_irq(&blkcg->lock); 780 goto update_io_group; 781 } 782 spin_unlock_irq(&blkcg->lock); 783 784 pn->weight = newpn->weight; 785 786update_io_group: 787 /* update weight for each cfqg */ 788 spin_lock(&blkio_list_lock); 789 spin_lock_irq(&blkcg->lock); 790 791 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 792 if (newpn->dev == blkg->dev) { 793 list_for_each_entry(blkiop, &blkio_list, list) 794 blkiop->ops.blkio_update_group_weight_fn(blkg, 795 newpn->weight ? 796 newpn->weight : 797 blkcg->weight); 798 } 799 } 800 801 spin_unlock_irq(&blkcg->lock); 802 spin_unlock(&blkio_list_lock); 803 804free_newpn: 805 if (!keep_newpn) 806 kfree(newpn); 807free_buf: 808 kfree(buf); 809 return ret; 810} 811 812static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft, 813 struct seq_file *m) 814{ 815 struct blkio_cgroup *blkcg; 816 struct blkio_policy_node *pn; 817 818 seq_printf(m, "dev\tweight\n"); 819 820 blkcg = cgroup_to_blkio_cgroup(cgrp); 821 if (list_empty(&blkcg->policy_list)) 822 goto out; 823 824 spin_lock_irq(&blkcg->lock); 825 list_for_each_entry(pn, &blkcg->policy_list, node) { 826 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), 827 MINOR(pn->dev), pn->weight); 828 } 829 spin_unlock_irq(&blkcg->lock); 830 831out: 832 return 0; 833} 834 835struct cftype blkio_files[] = { 836 { 837 .name = "weight_device", 838 .read_seq_string = blkiocg_weight_device_read, 839 .write_string = blkiocg_weight_device_write, 840 .max_write_len = 256, 841 }, 842 { 843 .name = "weight", 844 .read_u64 = blkiocg_weight_read, 845 .write_u64 = blkiocg_weight_write, 846 }, 847 { 848 .name = "time", 849 .read_map = blkiocg_time_read, 850 }, 851 { 852 .name = "sectors", 853 .read_map = blkiocg_sectors_read, 854 }, 855 { 856 .name = "io_service_bytes", 857 .read_map = blkiocg_io_service_bytes_read, 858 }, 859 { 860 .name = "io_serviced", 861 .read_map = blkiocg_io_serviced_read, 862 }, 863 { 864 .name = "io_service_time", 865 .read_map = blkiocg_io_service_time_read, 866 }, 867 { 868 .name = "io_wait_time", 869 .read_map = blkiocg_io_wait_time_read, 870 }, 871 { 872 .name = "io_merged", 873 .read_map = blkiocg_io_merged_read, 874 }, 875 { 876 .name = "io_queued", 877 .read_map = blkiocg_io_queued_read, 878 }, 879 { 880 .name = "reset_stats", 881 .write_u64 = blkiocg_reset_stats, 882 }, 883#ifdef CONFIG_DEBUG_BLK_CGROUP 884 { 885 .name = "avg_queue_size", 886 .read_map = blkiocg_avg_queue_size_read, 887 }, 888 { 889 .name = "group_wait_time", 890 .read_map = blkiocg_group_wait_time_read, 891 }, 892 { 893 .name = "idle_time", 894 .read_map = blkiocg_idle_time_read, 895 }, 896 { 897 .name = "empty_time", 898 .read_map = blkiocg_empty_time_read, 899 }, 900 { 901 .name = "dequeue", 902 .read_map = blkiocg_dequeue_read, 903 }, 904#endif 905}; 906 907static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) 908{ 909 return cgroup_add_files(cgroup, subsys, blkio_files, 910 ARRAY_SIZE(blkio_files)); 911} 912 913static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 914{ 915 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); 916 unsigned long flags; 917 struct blkio_group *blkg; 918 void *key; 919 struct blkio_policy_type *blkiop; 920 struct blkio_policy_node *pn, *pntmp; 921 922 rcu_read_lock(); 923remove_entry: 924 spin_lock_irqsave(&blkcg->lock, flags); 925 926 if (hlist_empty(&blkcg->blkg_list)) { 927 spin_unlock_irqrestore(&blkcg->lock, flags); 928 goto done; 929 } 930 931 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, 932 blkcg_node); 933 key = rcu_dereference(blkg->key); 934 __blkiocg_del_blkio_group(blkg); 935 936 spin_unlock_irqrestore(&blkcg->lock, flags); 937 938 /* 939 * This blkio_group is being unlinked as associated cgroup is going 940 * away. Let all the IO controlling policies know about this event. 941 * 942 * Currently this is static call to one io controlling policy. Once 943 * we have more policies in place, we need some dynamic registration 944 * of callback function. 945 */ 946 spin_lock(&blkio_list_lock); 947 list_for_each_entry(blkiop, &blkio_list, list) 948 blkiop->ops.blkio_unlink_group_fn(key, blkg); 949 spin_unlock(&blkio_list_lock); 950 goto remove_entry; 951 952done: 953 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) { 954 blkio_policy_delete_node(pn); 955 kfree(pn); 956 } 957 free_css_id(&blkio_subsys, &blkcg->css); 958 rcu_read_unlock(); 959 if (blkcg != &blkio_root_cgroup) 960 kfree(blkcg); 961} 962 963static struct cgroup_subsys_state * 964blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) 965{ 966 struct blkio_cgroup *blkcg, *parent_blkcg; 967 968 if (!cgroup->parent) { 969 blkcg = &blkio_root_cgroup; 970 goto done; 971 } 972 973 /* Currently we do not support hierarchy deeper than two level (0,1) */ 974 parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); 975 if (css_depth(&parent_blkcg->css) > 0) 976 return ERR_PTR(-EINVAL); 977 978 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); 979 if (!blkcg) 980 return ERR_PTR(-ENOMEM); 981 982 blkcg->weight = BLKIO_WEIGHT_DEFAULT; 983done: 984 spin_lock_init(&blkcg->lock); 985 INIT_HLIST_HEAD(&blkcg->blkg_list); 986 987 INIT_LIST_HEAD(&blkcg->policy_list); 988 return &blkcg->css; 989} 990 991/* 992 * We cannot support shared io contexts, as we have no mean to support 993 * two tasks with the same ioc in two different groups without major rework 994 * of the main cic data structures. For now we allow a task to change 995 * its cgroup only if it's the only owner of its ioc. 996 */ 997static int blkiocg_can_attach(struct cgroup_subsys *subsys, 998 struct cgroup *cgroup, struct task_struct *tsk, 999 bool threadgroup) 1000{ 1001 struct io_context *ioc; 1002 int ret = 0; 1003 1004 /* task_lock() is needed to avoid races with exit_io_context() */ 1005 task_lock(tsk); 1006 ioc = tsk->io_context; 1007 if (ioc && atomic_read(&ioc->nr_tasks) > 1) 1008 ret = -EINVAL; 1009 task_unlock(tsk); 1010 1011 return ret; 1012} 1013 1014static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, 1015 struct cgroup *prev, struct task_struct *tsk, 1016 bool threadgroup) 1017{ 1018 struct io_context *ioc; 1019 1020 task_lock(tsk); 1021 ioc = tsk->io_context; 1022 if (ioc) 1023 ioc->cgroup_changed = 1; 1024 task_unlock(tsk); 1025} 1026 1027void blkio_policy_register(struct blkio_policy_type *blkiop) 1028{ 1029 spin_lock(&blkio_list_lock); 1030 list_add_tail(&blkiop->list, &blkio_list); 1031 spin_unlock(&blkio_list_lock); 1032} 1033EXPORT_SYMBOL_GPL(blkio_policy_register); 1034 1035void blkio_policy_unregister(struct blkio_policy_type *blkiop) 1036{ 1037 spin_lock(&blkio_list_lock); 1038 list_del_init(&blkiop->list); 1039 spin_unlock(&blkio_list_lock); 1040} 1041EXPORT_SYMBOL_GPL(blkio_policy_unregister); 1042 1043static int __init init_cgroup_blkio(void) 1044{ 1045 return cgroup_load_subsys(&blkio_subsys); 1046} 1047 1048static void __exit exit_cgroup_blkio(void) 1049{ 1050 cgroup_unload_subsys(&blkio_subsys); 1051} 1052 1053module_init(init_cgroup_blkio); 1054module_exit(exit_cgroup_blkio); 1055MODULE_LICENSE("GPL"); 1056