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 <linux/slab.h> 20 #include "blk-cgroup.h" 21 #include <linux/genhd.h> 22 23 #define MAX_KEY_LEN 100 24 25 static DEFINE_SPINLOCK(blkio_list_lock); 26 static LIST_HEAD(blkio_list); 27 28 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; 29 EXPORT_SYMBOL_GPL(blkio_root_cgroup); 30 31 static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, 32 struct cgroup *); 33 static int blkiocg_can_attach_task(struct cgroup *, struct task_struct *); 34 static void blkiocg_attach_task(struct cgroup *, struct task_struct *); 35 static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); 36 static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); 37 38 /* for encoding cft->private value on file */ 39 #define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val)) 40 /* What policy owns the file, proportional or throttle */ 41 #define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff) 42 #define BLKIOFILE_ATTR(val) ((val) & 0xffff) 43 44 struct cgroup_subsys blkio_subsys = { 45 .name = "blkio", 46 .create = blkiocg_create, 47 .can_attach_task = blkiocg_can_attach_task, 48 .attach_task = blkiocg_attach_task, 49 .destroy = blkiocg_destroy, 50 .populate = blkiocg_populate, 51 #ifdef CONFIG_BLK_CGROUP 52 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ 53 .subsys_id = blkio_subsys_id, 54 #endif 55 .use_id = 1, 56 .module = THIS_MODULE, 57 }; 58 EXPORT_SYMBOL_GPL(blkio_subsys); 59 60 static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg, 61 struct blkio_policy_node *pn) 62 { 63 list_add(&pn->node, &blkcg->policy_list); 64 } 65 66 static inline bool cftype_blkg_same_policy(struct cftype *cft, 67 struct blkio_group *blkg) 68 { 69 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 70 71 if (blkg->plid == plid) 72 return 1; 73 74 return 0; 75 } 76 77 /* Determines if policy node matches cgroup file being accessed */ 78 static inline bool pn_matches_cftype(struct cftype *cft, 79 struct blkio_policy_node *pn) 80 { 81 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 82 int fileid = BLKIOFILE_ATTR(cft->private); 83 84 return (plid == pn->plid && fileid == pn->fileid); 85 } 86 87 /* Must be called with blkcg->lock held */ 88 static inline void blkio_policy_delete_node(struct blkio_policy_node *pn) 89 { 90 list_del(&pn->node); 91 } 92 93 /* Must be called with blkcg->lock held */ 94 static struct blkio_policy_node * 95 blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev, 96 enum blkio_policy_id plid, int fileid) 97 { 98 struct blkio_policy_node *pn; 99 100 list_for_each_entry(pn, &blkcg->policy_list, node) { 101 if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid) 102 return pn; 103 } 104 105 return NULL; 106 } 107 108 struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) 109 { 110 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), 111 struct blkio_cgroup, css); 112 } 113 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); 114 115 struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk) 116 { 117 return container_of(task_subsys_state(tsk, blkio_subsys_id), 118 struct blkio_cgroup, css); 119 } 120 EXPORT_SYMBOL_GPL(task_blkio_cgroup); 121 122 static inline void 123 blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight) 124 { 125 struct blkio_policy_type *blkiop; 126 127 list_for_each_entry(blkiop, &blkio_list, list) { 128 /* If this policy does not own the blkg, do not send updates */ 129 if (blkiop->plid != blkg->plid) 130 continue; 131 if (blkiop->ops.blkio_update_group_weight_fn) 132 blkiop->ops.blkio_update_group_weight_fn(blkg->key, 133 blkg, weight); 134 } 135 } 136 137 static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps, 138 int fileid) 139 { 140 struct blkio_policy_type *blkiop; 141 142 list_for_each_entry(blkiop, &blkio_list, list) { 143 144 /* If this policy does not own the blkg, do not send updates */ 145 if (blkiop->plid != blkg->plid) 146 continue; 147 148 if (fileid == BLKIO_THROTL_read_bps_device 149 && blkiop->ops.blkio_update_group_read_bps_fn) 150 blkiop->ops.blkio_update_group_read_bps_fn(blkg->key, 151 blkg, bps); 152 153 if (fileid == BLKIO_THROTL_write_bps_device 154 && blkiop->ops.blkio_update_group_write_bps_fn) 155 blkiop->ops.blkio_update_group_write_bps_fn(blkg->key, 156 blkg, bps); 157 } 158 } 159 160 static inline void blkio_update_group_iops(struct blkio_group *blkg, 161 unsigned int iops, int fileid) 162 { 163 struct blkio_policy_type *blkiop; 164 165 list_for_each_entry(blkiop, &blkio_list, list) { 166 167 /* If this policy does not own the blkg, do not send updates */ 168 if (blkiop->plid != blkg->plid) 169 continue; 170 171 if (fileid == BLKIO_THROTL_read_iops_device 172 && blkiop->ops.blkio_update_group_read_iops_fn) 173 blkiop->ops.blkio_update_group_read_iops_fn(blkg->key, 174 blkg, iops); 175 176 if (fileid == BLKIO_THROTL_write_iops_device 177 && blkiop->ops.blkio_update_group_write_iops_fn) 178 blkiop->ops.blkio_update_group_write_iops_fn(blkg->key, 179 blkg,iops); 180 } 181 } 182 183 /* 184 * Add to the appropriate stat variable depending on the request type. 185 * This should be called with the blkg->stats_lock held. 186 */ 187 static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, 188 bool sync) 189 { 190 if (direction) 191 stat[BLKIO_STAT_WRITE] += add; 192 else 193 stat[BLKIO_STAT_READ] += add; 194 if (sync) 195 stat[BLKIO_STAT_SYNC] += add; 196 else 197 stat[BLKIO_STAT_ASYNC] += add; 198 } 199 200 /* 201 * Decrements the appropriate stat variable if non-zero depending on the 202 * request type. Panics on value being zero. 203 * This should be called with the blkg->stats_lock held. 204 */ 205 static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync) 206 { 207 if (direction) { 208 BUG_ON(stat[BLKIO_STAT_WRITE] == 0); 209 stat[BLKIO_STAT_WRITE]--; 210 } else { 211 BUG_ON(stat[BLKIO_STAT_READ] == 0); 212 stat[BLKIO_STAT_READ]--; 213 } 214 if (sync) { 215 BUG_ON(stat[BLKIO_STAT_SYNC] == 0); 216 stat[BLKIO_STAT_SYNC]--; 217 } else { 218 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0); 219 stat[BLKIO_STAT_ASYNC]--; 220 } 221 } 222 223 #ifdef CONFIG_DEBUG_BLK_CGROUP 224 /* This should be called with the blkg->stats_lock held. */ 225 static void blkio_set_start_group_wait_time(struct blkio_group *blkg, 226 struct blkio_group *curr_blkg) 227 { 228 if (blkio_blkg_waiting(&blkg->stats)) 229 return; 230 if (blkg == curr_blkg) 231 return; 232 blkg->stats.start_group_wait_time = sched_clock(); 233 blkio_mark_blkg_waiting(&blkg->stats); 234 } 235 236 /* This should be called with the blkg->stats_lock held. */ 237 static void blkio_update_group_wait_time(struct blkio_group_stats *stats) 238 { 239 unsigned long long now; 240 241 if (!blkio_blkg_waiting(stats)) 242 return; 243 244 now = sched_clock(); 245 if (time_after64(now, stats->start_group_wait_time)) 246 stats->group_wait_time += now - stats->start_group_wait_time; 247 blkio_clear_blkg_waiting(stats); 248 } 249 250 /* This should be called with the blkg->stats_lock held. */ 251 static void blkio_end_empty_time(struct blkio_group_stats *stats) 252 { 253 unsigned long long now; 254 255 if (!blkio_blkg_empty(stats)) 256 return; 257 258 now = sched_clock(); 259 if (time_after64(now, stats->start_empty_time)) 260 stats->empty_time += now - stats->start_empty_time; 261 blkio_clear_blkg_empty(stats); 262 } 263 264 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) 265 { 266 unsigned long flags; 267 268 spin_lock_irqsave(&blkg->stats_lock, flags); 269 BUG_ON(blkio_blkg_idling(&blkg->stats)); 270 blkg->stats.start_idle_time = sched_clock(); 271 blkio_mark_blkg_idling(&blkg->stats); 272 spin_unlock_irqrestore(&blkg->stats_lock, flags); 273 } 274 EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats); 275 276 void blkiocg_update_idle_time_stats(struct blkio_group *blkg) 277 { 278 unsigned long flags; 279 unsigned long long now; 280 struct blkio_group_stats *stats; 281 282 spin_lock_irqsave(&blkg->stats_lock, flags); 283 stats = &blkg->stats; 284 if (blkio_blkg_idling(stats)) { 285 now = sched_clock(); 286 if (time_after64(now, stats->start_idle_time)) 287 stats->idle_time += now - stats->start_idle_time; 288 blkio_clear_blkg_idling(stats); 289 } 290 spin_unlock_irqrestore(&blkg->stats_lock, flags); 291 } 292 EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats); 293 294 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) 295 { 296 unsigned long flags; 297 struct blkio_group_stats *stats; 298 299 spin_lock_irqsave(&blkg->stats_lock, flags); 300 stats = &blkg->stats; 301 stats->avg_queue_size_sum += 302 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] + 303 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]; 304 stats->avg_queue_size_samples++; 305 blkio_update_group_wait_time(stats); 306 spin_unlock_irqrestore(&blkg->stats_lock, flags); 307 } 308 EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats); 309 310 void blkiocg_set_start_empty_time(struct blkio_group *blkg) 311 { 312 unsigned long flags; 313 struct blkio_group_stats *stats; 314 315 spin_lock_irqsave(&blkg->stats_lock, flags); 316 stats = &blkg->stats; 317 318 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] || 319 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) { 320 spin_unlock_irqrestore(&blkg->stats_lock, flags); 321 return; 322 } 323 324 /* 325 * group is already marked empty. This can happen if cfqq got new 326 * request in parent group and moved to this group while being added 327 * to service tree. Just ignore the event and move on. 328 */ 329 if(blkio_blkg_empty(stats)) { 330 spin_unlock_irqrestore(&blkg->stats_lock, flags); 331 return; 332 } 333 334 stats->start_empty_time = sched_clock(); 335 blkio_mark_blkg_empty(stats); 336 spin_unlock_irqrestore(&blkg->stats_lock, flags); 337 } 338 EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time); 339 340 void blkiocg_update_dequeue_stats(struct blkio_group *blkg, 341 unsigned long dequeue) 342 { 343 blkg->stats.dequeue += dequeue; 344 } 345 EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); 346 #else 347 static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg, 348 struct blkio_group *curr_blkg) {} 349 static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {} 350 #endif 351 352 void blkiocg_update_io_add_stats(struct blkio_group *blkg, 353 struct blkio_group *curr_blkg, bool direction, 354 bool sync) 355 { 356 unsigned long flags; 357 358 spin_lock_irqsave(&blkg->stats_lock, flags); 359 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction, 360 sync); 361 blkio_end_empty_time(&blkg->stats); 362 blkio_set_start_group_wait_time(blkg, curr_blkg); 363 spin_unlock_irqrestore(&blkg->stats_lock, flags); 364 } 365 EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats); 366 367 void blkiocg_update_io_remove_stats(struct blkio_group *blkg, 368 bool direction, bool sync) 369 { 370 unsigned long flags; 371 372 spin_lock_irqsave(&blkg->stats_lock, flags); 373 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 374 direction, sync); 375 spin_unlock_irqrestore(&blkg->stats_lock, flags); 376 } 377 EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats); 378 379 void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time, 380 unsigned long unaccounted_time) 381 { 382 unsigned long flags; 383 384 spin_lock_irqsave(&blkg->stats_lock, flags); 385 blkg->stats.time += time; 386 #ifdef CONFIG_DEBUG_BLK_CGROUP 387 blkg->stats.unaccounted_time += unaccounted_time; 388 #endif 389 spin_unlock_irqrestore(&blkg->stats_lock, flags); 390 } 391 EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); 392 393 /* 394 * should be called under rcu read lock or queue lock to make sure blkg pointer 395 * is valid. 396 */ 397 void blkiocg_update_dispatch_stats(struct blkio_group *blkg, 398 uint64_t bytes, bool direction, bool sync) 399 { 400 struct blkio_group_stats_cpu *stats_cpu; 401 unsigned long flags; 402 403 /* 404 * Disabling interrupts to provide mutual exclusion between two 405 * writes on same cpu. It probably is not needed for 64bit. Not 406 * optimizing that case yet. 407 */ 408 local_irq_save(flags); 409 410 stats_cpu = this_cpu_ptr(blkg->stats_cpu); 411 412 u64_stats_update_begin(&stats_cpu->syncp); 413 stats_cpu->sectors += bytes >> 9; 414 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED], 415 1, direction, sync); 416 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES], 417 bytes, direction, sync); 418 u64_stats_update_end(&stats_cpu->syncp); 419 local_irq_restore(flags); 420 } 421 EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); 422 423 void blkiocg_update_completion_stats(struct blkio_group *blkg, 424 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) 425 { 426 struct blkio_group_stats *stats; 427 unsigned long flags; 428 unsigned long long now = sched_clock(); 429 430 spin_lock_irqsave(&blkg->stats_lock, flags); 431 stats = &blkg->stats; 432 if (time_after64(now, io_start_time)) 433 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], 434 now - io_start_time, direction, sync); 435 if (time_after64(io_start_time, start_time)) 436 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], 437 io_start_time - start_time, direction, sync); 438 spin_unlock_irqrestore(&blkg->stats_lock, flags); 439 } 440 EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); 441 442 /* Merged stats are per cpu. */ 443 void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, 444 bool sync) 445 { 446 struct blkio_group_stats_cpu *stats_cpu; 447 unsigned long flags; 448 449 /* 450 * Disabling interrupts to provide mutual exclusion between two 451 * writes on same cpu. It probably is not needed for 64bit. Not 452 * optimizing that case yet. 453 */ 454 local_irq_save(flags); 455 456 stats_cpu = this_cpu_ptr(blkg->stats_cpu); 457 458 u64_stats_update_begin(&stats_cpu->syncp); 459 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1, 460 direction, sync); 461 u64_stats_update_end(&stats_cpu->syncp); 462 local_irq_restore(flags); 463 } 464 EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); 465 466 /* 467 * This function allocates the per cpu stats for blkio_group. Should be called 468 * from sleepable context as alloc_per_cpu() requires that. 469 */ 470 int blkio_alloc_blkg_stats(struct blkio_group *blkg) 471 { 472 /* Allocate memory for per cpu stats */ 473 blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu); 474 if (!blkg->stats_cpu) 475 return -ENOMEM; 476 return 0; 477 } 478 EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats); 479 480 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, 481 struct blkio_group *blkg, void *key, dev_t dev, 482 enum blkio_policy_id plid) 483 { 484 unsigned long flags; 485 486 spin_lock_irqsave(&blkcg->lock, flags); 487 spin_lock_init(&blkg->stats_lock); 488 rcu_assign_pointer(blkg->key, key); 489 blkg->blkcg_id = css_id(&blkcg->css); 490 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); 491 blkg->plid = plid; 492 spin_unlock_irqrestore(&blkcg->lock, flags); 493 /* Need to take css reference ? */ 494 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); 495 blkg->dev = dev; 496 } 497 EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); 498 499 static void __blkiocg_del_blkio_group(struct blkio_group *blkg) 500 { 501 hlist_del_init_rcu(&blkg->blkcg_node); 502 blkg->blkcg_id = 0; 503 } 504 505 /* 506 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 507 * indicating that blk_group was unhashed by the time we got to it. 508 */ 509 int blkiocg_del_blkio_group(struct blkio_group *blkg) 510 { 511 struct blkio_cgroup *blkcg; 512 unsigned long flags; 513 struct cgroup_subsys_state *css; 514 int ret = 1; 515 516 rcu_read_lock(); 517 css = css_lookup(&blkio_subsys, blkg->blkcg_id); 518 if (css) { 519 blkcg = container_of(css, struct blkio_cgroup, css); 520 spin_lock_irqsave(&blkcg->lock, flags); 521 if (!hlist_unhashed(&blkg->blkcg_node)) { 522 __blkiocg_del_blkio_group(blkg); 523 ret = 0; 524 } 525 spin_unlock_irqrestore(&blkcg->lock, flags); 526 } 527 528 rcu_read_unlock(); 529 return ret; 530 } 531 EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); 532 533 /* called under rcu_read_lock(). */ 534 struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) 535 { 536 struct blkio_group *blkg; 537 struct hlist_node *n; 538 void *__key; 539 540 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { 541 __key = blkg->key; 542 if (__key == key) 543 return blkg; 544 } 545 546 return NULL; 547 } 548 EXPORT_SYMBOL_GPL(blkiocg_lookup_group); 549 550 static void blkio_reset_stats_cpu(struct blkio_group *blkg) 551 { 552 struct blkio_group_stats_cpu *stats_cpu; 553 int i, j, k; 554 /* 555 * Note: On 64 bit arch this should not be an issue. This has the 556 * possibility of returning some inconsistent value on 32bit arch 557 * as 64bit update on 32bit is non atomic. Taking care of this 558 * corner case makes code very complicated, like sending IPIs to 559 * cpus, taking care of stats of offline cpus etc. 560 * 561 * reset stats is anyway more of a debug feature and this sounds a 562 * corner case. So I am not complicating the code yet until and 563 * unless this becomes a real issue. 564 */ 565 for_each_possible_cpu(i) { 566 stats_cpu = per_cpu_ptr(blkg->stats_cpu, i); 567 stats_cpu->sectors = 0; 568 for(j = 0; j < BLKIO_STAT_CPU_NR; j++) 569 for (k = 0; k < BLKIO_STAT_TOTAL; k++) 570 stats_cpu->stat_arr_cpu[j][k] = 0; 571 } 572 } 573 574 static int 575 blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) 576 { 577 struct blkio_cgroup *blkcg; 578 struct blkio_group *blkg; 579 struct blkio_group_stats *stats; 580 struct hlist_node *n; 581 uint64_t queued[BLKIO_STAT_TOTAL]; 582 int i; 583 #ifdef CONFIG_DEBUG_BLK_CGROUP 584 bool idling, waiting, empty; 585 unsigned long long now = sched_clock(); 586 #endif 587 588 blkcg = cgroup_to_blkio_cgroup(cgroup); 589 spin_lock_irq(&blkcg->lock); 590 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 591 spin_lock(&blkg->stats_lock); 592 stats = &blkg->stats; 593 #ifdef CONFIG_DEBUG_BLK_CGROUP 594 idling = blkio_blkg_idling(stats); 595 waiting = blkio_blkg_waiting(stats); 596 empty = blkio_blkg_empty(stats); 597 #endif 598 for (i = 0; i < BLKIO_STAT_TOTAL; i++) 599 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; 600 memset(stats, 0, sizeof(struct blkio_group_stats)); 601 for (i = 0; i < BLKIO_STAT_TOTAL; i++) 602 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; 603 #ifdef CONFIG_DEBUG_BLK_CGROUP 604 if (idling) { 605 blkio_mark_blkg_idling(stats); 606 stats->start_idle_time = now; 607 } 608 if (waiting) { 609 blkio_mark_blkg_waiting(stats); 610 stats->start_group_wait_time = now; 611 } 612 if (empty) { 613 blkio_mark_blkg_empty(stats); 614 stats->start_empty_time = now; 615 } 616 #endif 617 spin_unlock(&blkg->stats_lock); 618 619 /* Reset Per cpu stats which don't take blkg->stats_lock */ 620 blkio_reset_stats_cpu(blkg); 621 } 622 623 spin_unlock_irq(&blkcg->lock); 624 return 0; 625 } 626 627 static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, 628 int chars_left, bool diskname_only) 629 { 630 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); 631 chars_left -= strlen(str); 632 if (chars_left <= 0) { 633 printk(KERN_WARNING 634 "Possibly incorrect cgroup stat display format"); 635 return; 636 } 637 if (diskname_only) 638 return; 639 switch (type) { 640 case BLKIO_STAT_READ: 641 strlcat(str, " Read", chars_left); 642 break; 643 case BLKIO_STAT_WRITE: 644 strlcat(str, " Write", chars_left); 645 break; 646 case BLKIO_STAT_SYNC: 647 strlcat(str, " Sync", chars_left); 648 break; 649 case BLKIO_STAT_ASYNC: 650 strlcat(str, " Async", chars_left); 651 break; 652 case BLKIO_STAT_TOTAL: 653 strlcat(str, " Total", chars_left); 654 break; 655 default: 656 strlcat(str, " Invalid", chars_left); 657 } 658 } 659 660 static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, 661 struct cgroup_map_cb *cb, dev_t dev) 662 { 663 blkio_get_key_name(0, dev, str, chars_left, true); 664 cb->fill(cb, str, val); 665 return val; 666 } 667 668 669 static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg, 670 enum stat_type_cpu type, enum stat_sub_type sub_type) 671 { 672 int cpu; 673 struct blkio_group_stats_cpu *stats_cpu; 674 u64 val = 0, tval; 675 676 for_each_possible_cpu(cpu) { 677 unsigned int start; 678 stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu); 679 680 do { 681 start = u64_stats_fetch_begin(&stats_cpu->syncp); 682 if (type == BLKIO_STAT_CPU_SECTORS) 683 tval = stats_cpu->sectors; 684 else 685 tval = stats_cpu->stat_arr_cpu[type][sub_type]; 686 } while(u64_stats_fetch_retry(&stats_cpu->syncp, start)); 687 688 val += tval; 689 } 690 691 return val; 692 } 693 694 static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg, 695 struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type) 696 { 697 uint64_t disk_total, val; 698 char key_str[MAX_KEY_LEN]; 699 enum stat_sub_type sub_type; 700 701 if (type == BLKIO_STAT_CPU_SECTORS) { 702 val = blkio_read_stat_cpu(blkg, type, 0); 703 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev); 704 } 705 706 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; 707 sub_type++) { 708 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); 709 val = blkio_read_stat_cpu(blkg, type, sub_type); 710 cb->fill(cb, key_str, val); 711 } 712 713 disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) + 714 blkio_read_stat_cpu(blkg, type, BLKIO_STAT_WRITE); 715 716 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); 717 cb->fill(cb, key_str, disk_total); 718 return disk_total; 719 } 720 721 /* This should be called with blkg->stats_lock held */ 722 static uint64_t blkio_get_stat(struct blkio_group *blkg, 723 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) 724 { 725 uint64_t disk_total; 726 char key_str[MAX_KEY_LEN]; 727 enum stat_sub_type sub_type; 728 729 if (type == BLKIO_STAT_TIME) 730 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 731 blkg->stats.time, cb, dev); 732 #ifdef CONFIG_DEBUG_BLK_CGROUP 733 if (type == BLKIO_STAT_UNACCOUNTED_TIME) 734 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 735 blkg->stats.unaccounted_time, cb, dev); 736 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { 737 uint64_t sum = blkg->stats.avg_queue_size_sum; 738 uint64_t samples = blkg->stats.avg_queue_size_samples; 739 if (samples) 740 do_div(sum, samples); 741 else 742 sum = 0; 743 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); 744 } 745 if (type == BLKIO_STAT_GROUP_WAIT_TIME) 746 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 747 blkg->stats.group_wait_time, cb, dev); 748 if (type == BLKIO_STAT_IDLE_TIME) 749 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 750 blkg->stats.idle_time, cb, dev); 751 if (type == BLKIO_STAT_EMPTY_TIME) 752 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 753 blkg->stats.empty_time, cb, dev); 754 if (type == BLKIO_STAT_DEQUEUE) 755 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, 756 blkg->stats.dequeue, cb, dev); 757 #endif 758 759 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; 760 sub_type++) { 761 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); 762 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); 763 } 764 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + 765 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; 766 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); 767 cb->fill(cb, key_str, disk_total); 768 return disk_total; 769 } 770 771 static int blkio_check_dev_num(dev_t dev) 772 { 773 int part = 0; 774 struct gendisk *disk; 775 776 disk = get_gendisk(dev, &part); 777 if (!disk || part) 778 return -ENODEV; 779 780 return 0; 781 } 782 783 static int blkio_policy_parse_and_set(char *buf, 784 struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid) 785 { 786 char *s[4], *p, *major_s = NULL, *minor_s = NULL; 787 int ret; 788 unsigned long major, minor, temp; 789 int i = 0; 790 dev_t dev; 791 u64 bps, iops; 792 793 memset(s, 0, sizeof(s)); 794 795 while ((p = strsep(&buf, " ")) != NULL) { 796 if (!*p) 797 continue; 798 799 s[i++] = p; 800 801 /* Prevent from inputing too many things */ 802 if (i == 3) 803 break; 804 } 805 806 if (i != 2) 807 return -EINVAL; 808 809 p = strsep(&s[0], ":"); 810 if (p != NULL) 811 major_s = p; 812 else 813 return -EINVAL; 814 815 minor_s = s[0]; 816 if (!minor_s) 817 return -EINVAL; 818 819 ret = strict_strtoul(major_s, 10, &major); 820 if (ret) 821 return -EINVAL; 822 823 ret = strict_strtoul(minor_s, 10, &minor); 824 if (ret) 825 return -EINVAL; 826 827 dev = MKDEV(major, minor); 828 829 ret = blkio_check_dev_num(dev); 830 if (ret) 831 return ret; 832 833 newpn->dev = dev; 834 835 if (s[1] == NULL) 836 return -EINVAL; 837 838 switch (plid) { 839 case BLKIO_POLICY_PROP: 840 ret = strict_strtoul(s[1], 10, &temp); 841 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || 842 temp > BLKIO_WEIGHT_MAX) 843 return -EINVAL; 844 845 newpn->plid = plid; 846 newpn->fileid = fileid; 847 newpn->val.weight = temp; 848 break; 849 case BLKIO_POLICY_THROTL: 850 switch(fileid) { 851 case BLKIO_THROTL_read_bps_device: 852 case BLKIO_THROTL_write_bps_device: 853 ret = strict_strtoull(s[1], 10, &bps); 854 if (ret) 855 return -EINVAL; 856 857 newpn->plid = plid; 858 newpn->fileid = fileid; 859 newpn->val.bps = bps; 860 break; 861 case BLKIO_THROTL_read_iops_device: 862 case BLKIO_THROTL_write_iops_device: 863 ret = strict_strtoull(s[1], 10, &iops); 864 if (ret) 865 return -EINVAL; 866 867 if (iops > THROTL_IOPS_MAX) 868 return -EINVAL; 869 870 newpn->plid = plid; 871 newpn->fileid = fileid; 872 newpn->val.iops = (unsigned int)iops; 873 break; 874 } 875 break; 876 default: 877 BUG(); 878 } 879 880 return 0; 881 } 882 883 unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, 884 dev_t dev) 885 { 886 struct blkio_policy_node *pn; 887 888 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP, 889 BLKIO_PROP_weight_device); 890 if (pn) 891 return pn->val.weight; 892 else 893 return blkcg->weight; 894 } 895 EXPORT_SYMBOL_GPL(blkcg_get_weight); 896 897 uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev) 898 { 899 struct blkio_policy_node *pn; 900 901 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, 902 BLKIO_THROTL_read_bps_device); 903 if (pn) 904 return pn->val.bps; 905 else 906 return -1; 907 } 908 909 uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev) 910 { 911 struct blkio_policy_node *pn; 912 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, 913 BLKIO_THROTL_write_bps_device); 914 if (pn) 915 return pn->val.bps; 916 else 917 return -1; 918 } 919 920 unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev) 921 { 922 struct blkio_policy_node *pn; 923 924 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, 925 BLKIO_THROTL_read_iops_device); 926 if (pn) 927 return pn->val.iops; 928 else 929 return -1; 930 } 931 932 unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev) 933 { 934 struct blkio_policy_node *pn; 935 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, 936 BLKIO_THROTL_write_iops_device); 937 if (pn) 938 return pn->val.iops; 939 else 940 return -1; 941 } 942 943 /* Checks whether user asked for deleting a policy rule */ 944 static bool blkio_delete_rule_command(struct blkio_policy_node *pn) 945 { 946 switch(pn->plid) { 947 case BLKIO_POLICY_PROP: 948 if (pn->val.weight == 0) 949 return 1; 950 break; 951 case BLKIO_POLICY_THROTL: 952 switch(pn->fileid) { 953 case BLKIO_THROTL_read_bps_device: 954 case BLKIO_THROTL_write_bps_device: 955 if (pn->val.bps == 0) 956 return 1; 957 break; 958 case BLKIO_THROTL_read_iops_device: 959 case BLKIO_THROTL_write_iops_device: 960 if (pn->val.iops == 0) 961 return 1; 962 } 963 break; 964 default: 965 BUG(); 966 } 967 968 return 0; 969 } 970 971 static void blkio_update_policy_rule(struct blkio_policy_node *oldpn, 972 struct blkio_policy_node *newpn) 973 { 974 switch(oldpn->plid) { 975 case BLKIO_POLICY_PROP: 976 oldpn->val.weight = newpn->val.weight; 977 break; 978 case BLKIO_POLICY_THROTL: 979 switch(newpn->fileid) { 980 case BLKIO_THROTL_read_bps_device: 981 case BLKIO_THROTL_write_bps_device: 982 oldpn->val.bps = newpn->val.bps; 983 break; 984 case BLKIO_THROTL_read_iops_device: 985 case BLKIO_THROTL_write_iops_device: 986 oldpn->val.iops = newpn->val.iops; 987 } 988 break; 989 default: 990 BUG(); 991 } 992 } 993 994 /* 995 * Some rules/values in blkg have changed. Propagate those to respective 996 * policies. 997 */ 998 static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg, 999 struct blkio_group *blkg, struct blkio_policy_node *pn) 1000 { 1001 unsigned int weight, iops; 1002 u64 bps; 1003 1004 switch(pn->plid) { 1005 case BLKIO_POLICY_PROP: 1006 weight = pn->val.weight ? pn->val.weight : 1007 blkcg->weight; 1008 blkio_update_group_weight(blkg, weight); 1009 break; 1010 case BLKIO_POLICY_THROTL: 1011 switch(pn->fileid) { 1012 case BLKIO_THROTL_read_bps_device: 1013 case BLKIO_THROTL_write_bps_device: 1014 bps = pn->val.bps ? pn->val.bps : (-1); 1015 blkio_update_group_bps(blkg, bps, pn->fileid); 1016 break; 1017 case BLKIO_THROTL_read_iops_device: 1018 case BLKIO_THROTL_write_iops_device: 1019 iops = pn->val.iops ? pn->val.iops : (-1); 1020 blkio_update_group_iops(blkg, iops, pn->fileid); 1021 break; 1022 } 1023 break; 1024 default: 1025 BUG(); 1026 } 1027 } 1028 1029 /* 1030 * A policy node rule has been updated. Propagate this update to all the 1031 * block groups which might be affected by this update. 1032 */ 1033 static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg, 1034 struct blkio_policy_node *pn) 1035 { 1036 struct blkio_group *blkg; 1037 struct hlist_node *n; 1038 1039 spin_lock(&blkio_list_lock); 1040 spin_lock_irq(&blkcg->lock); 1041 1042 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 1043 if (pn->dev != blkg->dev || pn->plid != blkg->plid) 1044 continue; 1045 blkio_update_blkg_policy(blkcg, blkg, pn); 1046 } 1047 1048 spin_unlock_irq(&blkcg->lock); 1049 spin_unlock(&blkio_list_lock); 1050 } 1051 1052 static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft, 1053 const char *buffer) 1054 { 1055 int ret = 0; 1056 char *buf; 1057 struct blkio_policy_node *newpn, *pn; 1058 struct blkio_cgroup *blkcg; 1059 int keep_newpn = 0; 1060 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 1061 int fileid = BLKIOFILE_ATTR(cft->private); 1062 1063 buf = kstrdup(buffer, GFP_KERNEL); 1064 if (!buf) 1065 return -ENOMEM; 1066 1067 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL); 1068 if (!newpn) { 1069 ret = -ENOMEM; 1070 goto free_buf; 1071 } 1072 1073 ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid); 1074 if (ret) 1075 goto free_newpn; 1076 1077 blkcg = cgroup_to_blkio_cgroup(cgrp); 1078 1079 spin_lock_irq(&blkcg->lock); 1080 1081 pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid); 1082 if (!pn) { 1083 if (!blkio_delete_rule_command(newpn)) { 1084 blkio_policy_insert_node(blkcg, newpn); 1085 keep_newpn = 1; 1086 } 1087 spin_unlock_irq(&blkcg->lock); 1088 goto update_io_group; 1089 } 1090 1091 if (blkio_delete_rule_command(newpn)) { 1092 blkio_policy_delete_node(pn); 1093 spin_unlock_irq(&blkcg->lock); 1094 goto update_io_group; 1095 } 1096 spin_unlock_irq(&blkcg->lock); 1097 1098 blkio_update_policy_rule(pn, newpn); 1099 1100 update_io_group: 1101 blkio_update_policy_node_blkg(blkcg, newpn); 1102 1103 free_newpn: 1104 if (!keep_newpn) 1105 kfree(newpn); 1106 free_buf: 1107 kfree(buf); 1108 return ret; 1109 } 1110 1111 static void 1112 blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn) 1113 { 1114 switch(pn->plid) { 1115 case BLKIO_POLICY_PROP: 1116 if (pn->fileid == BLKIO_PROP_weight_device) 1117 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), 1118 MINOR(pn->dev), pn->val.weight); 1119 break; 1120 case BLKIO_POLICY_THROTL: 1121 switch(pn->fileid) { 1122 case BLKIO_THROTL_read_bps_device: 1123 case BLKIO_THROTL_write_bps_device: 1124 seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev), 1125 MINOR(pn->dev), pn->val.bps); 1126 break; 1127 case BLKIO_THROTL_read_iops_device: 1128 case BLKIO_THROTL_write_iops_device: 1129 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), 1130 MINOR(pn->dev), pn->val.iops); 1131 break; 1132 } 1133 break; 1134 default: 1135 BUG(); 1136 } 1137 } 1138 1139 /* cgroup files which read their data from policy nodes end up here */ 1140 static void blkio_read_policy_node_files(struct cftype *cft, 1141 struct blkio_cgroup *blkcg, struct seq_file *m) 1142 { 1143 struct blkio_policy_node *pn; 1144 1145 if (!list_empty(&blkcg->policy_list)) { 1146 spin_lock_irq(&blkcg->lock); 1147 list_for_each_entry(pn, &blkcg->policy_list, node) { 1148 if (!pn_matches_cftype(cft, pn)) 1149 continue; 1150 blkio_print_policy_node(m, pn); 1151 } 1152 spin_unlock_irq(&blkcg->lock); 1153 } 1154 } 1155 1156 static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft, 1157 struct seq_file *m) 1158 { 1159 struct blkio_cgroup *blkcg; 1160 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 1161 int name = BLKIOFILE_ATTR(cft->private); 1162 1163 blkcg = cgroup_to_blkio_cgroup(cgrp); 1164 1165 switch(plid) { 1166 case BLKIO_POLICY_PROP: 1167 switch(name) { 1168 case BLKIO_PROP_weight_device: 1169 blkio_read_policy_node_files(cft, blkcg, m); 1170 return 0; 1171 default: 1172 BUG(); 1173 } 1174 break; 1175 case BLKIO_POLICY_THROTL: 1176 switch(name){ 1177 case BLKIO_THROTL_read_bps_device: 1178 case BLKIO_THROTL_write_bps_device: 1179 case BLKIO_THROTL_read_iops_device: 1180 case BLKIO_THROTL_write_iops_device: 1181 blkio_read_policy_node_files(cft, blkcg, m); 1182 return 0; 1183 default: 1184 BUG(); 1185 } 1186 break; 1187 default: 1188 BUG(); 1189 } 1190 1191 return 0; 1192 } 1193 1194 static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg, 1195 struct cftype *cft, struct cgroup_map_cb *cb, 1196 enum stat_type type, bool show_total, bool pcpu) 1197 { 1198 struct blkio_group *blkg; 1199 struct hlist_node *n; 1200 uint64_t cgroup_total = 0; 1201 1202 rcu_read_lock(); 1203 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { 1204 if (blkg->dev) { 1205 if (!cftype_blkg_same_policy(cft, blkg)) 1206 continue; 1207 if (pcpu) 1208 cgroup_total += blkio_get_stat_cpu(blkg, cb, 1209 blkg->dev, type); 1210 else { 1211 spin_lock_irq(&blkg->stats_lock); 1212 cgroup_total += blkio_get_stat(blkg, cb, 1213 blkg->dev, type); 1214 spin_unlock_irq(&blkg->stats_lock); 1215 } 1216 } 1217 } 1218 if (show_total) 1219 cb->fill(cb, "Total", cgroup_total); 1220 rcu_read_unlock(); 1221 return 0; 1222 } 1223 1224 /* All map kind of cgroup file get serviced by this function */ 1225 static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft, 1226 struct cgroup_map_cb *cb) 1227 { 1228 struct blkio_cgroup *blkcg; 1229 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 1230 int name = BLKIOFILE_ATTR(cft->private); 1231 1232 blkcg = cgroup_to_blkio_cgroup(cgrp); 1233 1234 switch(plid) { 1235 case BLKIO_POLICY_PROP: 1236 switch(name) { 1237 case BLKIO_PROP_time: 1238 return blkio_read_blkg_stats(blkcg, cft, cb, 1239 BLKIO_STAT_TIME, 0, 0); 1240 case BLKIO_PROP_sectors: 1241 return blkio_read_blkg_stats(blkcg, cft, cb, 1242 BLKIO_STAT_CPU_SECTORS, 0, 1); 1243 case BLKIO_PROP_io_service_bytes: 1244 return blkio_read_blkg_stats(blkcg, cft, cb, 1245 BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1); 1246 case BLKIO_PROP_io_serviced: 1247 return blkio_read_blkg_stats(blkcg, cft, cb, 1248 BLKIO_STAT_CPU_SERVICED, 1, 1); 1249 case BLKIO_PROP_io_service_time: 1250 return blkio_read_blkg_stats(blkcg, cft, cb, 1251 BLKIO_STAT_SERVICE_TIME, 1, 0); 1252 case BLKIO_PROP_io_wait_time: 1253 return blkio_read_blkg_stats(blkcg, cft, cb, 1254 BLKIO_STAT_WAIT_TIME, 1, 0); 1255 case BLKIO_PROP_io_merged: 1256 return blkio_read_blkg_stats(blkcg, cft, cb, 1257 BLKIO_STAT_CPU_MERGED, 1, 1); 1258 case BLKIO_PROP_io_queued: 1259 return blkio_read_blkg_stats(blkcg, cft, cb, 1260 BLKIO_STAT_QUEUED, 1, 0); 1261 #ifdef CONFIG_DEBUG_BLK_CGROUP 1262 case BLKIO_PROP_unaccounted_time: 1263 return blkio_read_blkg_stats(blkcg, cft, cb, 1264 BLKIO_STAT_UNACCOUNTED_TIME, 0, 0); 1265 case BLKIO_PROP_dequeue: 1266 return blkio_read_blkg_stats(blkcg, cft, cb, 1267 BLKIO_STAT_DEQUEUE, 0, 0); 1268 case BLKIO_PROP_avg_queue_size: 1269 return blkio_read_blkg_stats(blkcg, cft, cb, 1270 BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0); 1271 case BLKIO_PROP_group_wait_time: 1272 return blkio_read_blkg_stats(blkcg, cft, cb, 1273 BLKIO_STAT_GROUP_WAIT_TIME, 0, 0); 1274 case BLKIO_PROP_idle_time: 1275 return blkio_read_blkg_stats(blkcg, cft, cb, 1276 BLKIO_STAT_IDLE_TIME, 0, 0); 1277 case BLKIO_PROP_empty_time: 1278 return blkio_read_blkg_stats(blkcg, cft, cb, 1279 BLKIO_STAT_EMPTY_TIME, 0, 0); 1280 #endif 1281 default: 1282 BUG(); 1283 } 1284 break; 1285 case BLKIO_POLICY_THROTL: 1286 switch(name){ 1287 case BLKIO_THROTL_io_service_bytes: 1288 return blkio_read_blkg_stats(blkcg, cft, cb, 1289 BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1); 1290 case BLKIO_THROTL_io_serviced: 1291 return blkio_read_blkg_stats(blkcg, cft, cb, 1292 BLKIO_STAT_CPU_SERVICED, 1, 1); 1293 default: 1294 BUG(); 1295 } 1296 break; 1297 default: 1298 BUG(); 1299 } 1300 1301 return 0; 1302 } 1303 1304 static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val) 1305 { 1306 struct blkio_group *blkg; 1307 struct hlist_node *n; 1308 struct blkio_policy_node *pn; 1309 1310 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) 1311 return -EINVAL; 1312 1313 spin_lock(&blkio_list_lock); 1314 spin_lock_irq(&blkcg->lock); 1315 blkcg->weight = (unsigned int)val; 1316 1317 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { 1318 pn = blkio_policy_search_node(blkcg, blkg->dev, 1319 BLKIO_POLICY_PROP, BLKIO_PROP_weight_device); 1320 if (pn) 1321 continue; 1322 1323 blkio_update_group_weight(blkg, blkcg->weight); 1324 } 1325 spin_unlock_irq(&blkcg->lock); 1326 spin_unlock(&blkio_list_lock); 1327 return 0; 1328 } 1329 1330 static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) { 1331 struct blkio_cgroup *blkcg; 1332 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 1333 int name = BLKIOFILE_ATTR(cft->private); 1334 1335 blkcg = cgroup_to_blkio_cgroup(cgrp); 1336 1337 switch(plid) { 1338 case BLKIO_POLICY_PROP: 1339 switch(name) { 1340 case BLKIO_PROP_weight: 1341 return (u64)blkcg->weight; 1342 } 1343 break; 1344 default: 1345 BUG(); 1346 } 1347 return 0; 1348 } 1349 1350 static int 1351 blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val) 1352 { 1353 struct blkio_cgroup *blkcg; 1354 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); 1355 int name = BLKIOFILE_ATTR(cft->private); 1356 1357 blkcg = cgroup_to_blkio_cgroup(cgrp); 1358 1359 switch(plid) { 1360 case BLKIO_POLICY_PROP: 1361 switch(name) { 1362 case BLKIO_PROP_weight: 1363 return blkio_weight_write(blkcg, val); 1364 } 1365 break; 1366 default: 1367 BUG(); 1368 } 1369 1370 return 0; 1371 } 1372 1373 struct cftype blkio_files[] = { 1374 { 1375 .name = "weight_device", 1376 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1377 BLKIO_PROP_weight_device), 1378 .read_seq_string = blkiocg_file_read, 1379 .write_string = blkiocg_file_write, 1380 .max_write_len = 256, 1381 }, 1382 { 1383 .name = "weight", 1384 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1385 BLKIO_PROP_weight), 1386 .read_u64 = blkiocg_file_read_u64, 1387 .write_u64 = blkiocg_file_write_u64, 1388 }, 1389 { 1390 .name = "time", 1391 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1392 BLKIO_PROP_time), 1393 .read_map = blkiocg_file_read_map, 1394 }, 1395 { 1396 .name = "sectors", 1397 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1398 BLKIO_PROP_sectors), 1399 .read_map = blkiocg_file_read_map, 1400 }, 1401 { 1402 .name = "io_service_bytes", 1403 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1404 BLKIO_PROP_io_service_bytes), 1405 .read_map = blkiocg_file_read_map, 1406 }, 1407 { 1408 .name = "io_serviced", 1409 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1410 BLKIO_PROP_io_serviced), 1411 .read_map = blkiocg_file_read_map, 1412 }, 1413 { 1414 .name = "io_service_time", 1415 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1416 BLKIO_PROP_io_service_time), 1417 .read_map = blkiocg_file_read_map, 1418 }, 1419 { 1420 .name = "io_wait_time", 1421 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1422 BLKIO_PROP_io_wait_time), 1423 .read_map = blkiocg_file_read_map, 1424 }, 1425 { 1426 .name = "io_merged", 1427 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1428 BLKIO_PROP_io_merged), 1429 .read_map = blkiocg_file_read_map, 1430 }, 1431 { 1432 .name = "io_queued", 1433 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1434 BLKIO_PROP_io_queued), 1435 .read_map = blkiocg_file_read_map, 1436 }, 1437 { 1438 .name = "reset_stats", 1439 .write_u64 = blkiocg_reset_stats, 1440 }, 1441 #ifdef CONFIG_BLK_DEV_THROTTLING 1442 { 1443 .name = "throttle.read_bps_device", 1444 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1445 BLKIO_THROTL_read_bps_device), 1446 .read_seq_string = blkiocg_file_read, 1447 .write_string = blkiocg_file_write, 1448 .max_write_len = 256, 1449 }, 1450 1451 { 1452 .name = "throttle.write_bps_device", 1453 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1454 BLKIO_THROTL_write_bps_device), 1455 .read_seq_string = blkiocg_file_read, 1456 .write_string = blkiocg_file_write, 1457 .max_write_len = 256, 1458 }, 1459 1460 { 1461 .name = "throttle.read_iops_device", 1462 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1463 BLKIO_THROTL_read_iops_device), 1464 .read_seq_string = blkiocg_file_read, 1465 .write_string = blkiocg_file_write, 1466 .max_write_len = 256, 1467 }, 1468 1469 { 1470 .name = "throttle.write_iops_device", 1471 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1472 BLKIO_THROTL_write_iops_device), 1473 .read_seq_string = blkiocg_file_read, 1474 .write_string = blkiocg_file_write, 1475 .max_write_len = 256, 1476 }, 1477 { 1478 .name = "throttle.io_service_bytes", 1479 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1480 BLKIO_THROTL_io_service_bytes), 1481 .read_map = blkiocg_file_read_map, 1482 }, 1483 { 1484 .name = "throttle.io_serviced", 1485 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, 1486 BLKIO_THROTL_io_serviced), 1487 .read_map = blkiocg_file_read_map, 1488 }, 1489 #endif /* CONFIG_BLK_DEV_THROTTLING */ 1490 1491 #ifdef CONFIG_DEBUG_BLK_CGROUP 1492 { 1493 .name = "avg_queue_size", 1494 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1495 BLKIO_PROP_avg_queue_size), 1496 .read_map = blkiocg_file_read_map, 1497 }, 1498 { 1499 .name = "group_wait_time", 1500 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1501 BLKIO_PROP_group_wait_time), 1502 .read_map = blkiocg_file_read_map, 1503 }, 1504 { 1505 .name = "idle_time", 1506 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1507 BLKIO_PROP_idle_time), 1508 .read_map = blkiocg_file_read_map, 1509 }, 1510 { 1511 .name = "empty_time", 1512 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1513 BLKIO_PROP_empty_time), 1514 .read_map = blkiocg_file_read_map, 1515 }, 1516 { 1517 .name = "dequeue", 1518 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1519 BLKIO_PROP_dequeue), 1520 .read_map = blkiocg_file_read_map, 1521 }, 1522 { 1523 .name = "unaccounted_time", 1524 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, 1525 BLKIO_PROP_unaccounted_time), 1526 .read_map = blkiocg_file_read_map, 1527 }, 1528 #endif 1529 }; 1530 1531 static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) 1532 { 1533 return cgroup_add_files(cgroup, subsys, blkio_files, 1534 ARRAY_SIZE(blkio_files)); 1535 } 1536 1537 static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 1538 { 1539 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); 1540 unsigned long flags; 1541 struct blkio_group *blkg; 1542 void *key; 1543 struct blkio_policy_type *blkiop; 1544 struct blkio_policy_node *pn, *pntmp; 1545 1546 rcu_read_lock(); 1547 do { 1548 spin_lock_irqsave(&blkcg->lock, flags); 1549 1550 if (hlist_empty(&blkcg->blkg_list)) { 1551 spin_unlock_irqrestore(&blkcg->lock, flags); 1552 break; 1553 } 1554 1555 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, 1556 blkcg_node); 1557 key = rcu_dereference(blkg->key); 1558 __blkiocg_del_blkio_group(blkg); 1559 1560 spin_unlock_irqrestore(&blkcg->lock, flags); 1561 1562 /* 1563 * This blkio_group is being unlinked as associated cgroup is 1564 * going away. Let all the IO controlling policies know about 1565 * this event. 1566 */ 1567 spin_lock(&blkio_list_lock); 1568 list_for_each_entry(blkiop, &blkio_list, list) { 1569 if (blkiop->plid != blkg->plid) 1570 continue; 1571 blkiop->ops.blkio_unlink_group_fn(key, blkg); 1572 } 1573 spin_unlock(&blkio_list_lock); 1574 } while (1); 1575 1576 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) { 1577 blkio_policy_delete_node(pn); 1578 kfree(pn); 1579 } 1580 1581 free_css_id(&blkio_subsys, &blkcg->css); 1582 rcu_read_unlock(); 1583 if (blkcg != &blkio_root_cgroup) 1584 kfree(blkcg); 1585 } 1586 1587 static struct cgroup_subsys_state * 1588 blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) 1589 { 1590 struct blkio_cgroup *blkcg; 1591 struct cgroup *parent = cgroup->parent; 1592 1593 if (!parent) { 1594 blkcg = &blkio_root_cgroup; 1595 goto done; 1596 } 1597 1598 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); 1599 if (!blkcg) 1600 return ERR_PTR(-ENOMEM); 1601 1602 blkcg->weight = BLKIO_WEIGHT_DEFAULT; 1603 done: 1604 spin_lock_init(&blkcg->lock); 1605 INIT_HLIST_HEAD(&blkcg->blkg_list); 1606 1607 INIT_LIST_HEAD(&blkcg->policy_list); 1608 return &blkcg->css; 1609 } 1610 1611 /* 1612 * We cannot support shared io contexts, as we have no mean to support 1613 * two tasks with the same ioc in two different groups without major rework 1614 * of the main cic data structures. For now we allow a task to change 1615 * its cgroup only if it's the only owner of its ioc. 1616 */ 1617 static int blkiocg_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk) 1618 { 1619 struct io_context *ioc; 1620 int ret = 0; 1621 1622 /* task_lock() is needed to avoid races with exit_io_context() */ 1623 task_lock(tsk); 1624 ioc = tsk->io_context; 1625 if (ioc && atomic_read(&ioc->nr_tasks) > 1) 1626 ret = -EINVAL; 1627 task_unlock(tsk); 1628 1629 return ret; 1630 } 1631 1632 static void blkiocg_attach_task(struct cgroup *cgrp, struct task_struct *tsk) 1633 { 1634 struct io_context *ioc; 1635 1636 task_lock(tsk); 1637 ioc = tsk->io_context; 1638 if (ioc) 1639 ioc->cgroup_changed = 1; 1640 task_unlock(tsk); 1641 } 1642 1643 void blkio_policy_register(struct blkio_policy_type *blkiop) 1644 { 1645 spin_lock(&blkio_list_lock); 1646 list_add_tail(&blkiop->list, &blkio_list); 1647 spin_unlock(&blkio_list_lock); 1648 } 1649 EXPORT_SYMBOL_GPL(blkio_policy_register); 1650 1651 void blkio_policy_unregister(struct blkio_policy_type *blkiop) 1652 { 1653 spin_lock(&blkio_list_lock); 1654 list_del_init(&blkiop->list); 1655 spin_unlock(&blkio_list_lock); 1656 } 1657 EXPORT_SYMBOL_GPL(blkio_policy_unregister); 1658 1659 static int __init init_cgroup_blkio(void) 1660 { 1661 return cgroup_load_subsys(&blkio_subsys); 1662 } 1663 1664 static void __exit exit_cgroup_blkio(void) 1665 { 1666 cgroup_unload_subsys(&blkio_subsys); 1667 } 1668 1669 module_init(init_cgroup_blkio); 1670 module_exit(exit_cgroup_blkio); 1671 MODULE_LICENSE("GPL"); 1672