1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/errno.h> 3 #include <linux/numa.h> 4 #include <linux/slab.h> 5 #include <linux/rculist.h> 6 #include <linux/threads.h> 7 #include <linux/preempt.h> 8 #include <linux/irqflags.h> 9 #include <linux/vmalloc.h> 10 #include <linux/mm.h> 11 #include <linux/module.h> 12 #include <linux/device-mapper.h> 13 14 #include "dm-core.h" 15 #include "dm-stats.h" 16 17 #define DM_MSG_PREFIX "stats" 18 19 static int dm_stat_need_rcu_barrier; 20 21 /* 22 * Using 64-bit values to avoid overflow (which is a 23 * problem that block/genhd.c's IO accounting has). 24 */ 25 struct dm_stat_percpu { 26 unsigned long long sectors[2]; 27 unsigned long long ios[2]; 28 unsigned long long merges[2]; 29 unsigned long long ticks[2]; 30 unsigned long long io_ticks[2]; 31 unsigned long long io_ticks_total; 32 unsigned long long time_in_queue; 33 unsigned long long *histogram; 34 }; 35 36 struct dm_stat_shared { 37 atomic_t in_flight[2]; 38 unsigned long long stamp; 39 struct dm_stat_percpu tmp; 40 }; 41 42 struct dm_stat { 43 struct list_head list_entry; 44 int id; 45 unsigned stat_flags; 46 size_t n_entries; 47 sector_t start; 48 sector_t end; 49 sector_t step; 50 unsigned n_histogram_entries; 51 unsigned long long *histogram_boundaries; 52 const char *program_id; 53 const char *aux_data; 54 struct rcu_head rcu_head; 55 size_t shared_alloc_size; 56 size_t percpu_alloc_size; 57 size_t histogram_alloc_size; 58 struct dm_stat_percpu *stat_percpu[NR_CPUS]; 59 struct dm_stat_shared stat_shared[]; 60 }; 61 62 #define STAT_PRECISE_TIMESTAMPS 1 63 64 struct dm_stats_last_position { 65 sector_t last_sector; 66 unsigned last_rw; 67 }; 68 69 /* 70 * A typo on the command line could possibly make the kernel run out of memory 71 * and crash. To prevent the crash we account all used memory. We fail if we 72 * exhaust 1/4 of all memory or 1/2 of vmalloc space. 73 */ 74 #define DM_STATS_MEMORY_FACTOR 4 75 #define DM_STATS_VMALLOC_FACTOR 2 76 77 static DEFINE_SPINLOCK(shared_memory_lock); 78 79 static unsigned long shared_memory_amount; 80 81 static bool __check_shared_memory(size_t alloc_size) 82 { 83 size_t a; 84 85 a = shared_memory_amount + alloc_size; 86 if (a < shared_memory_amount) 87 return false; 88 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR) 89 return false; 90 #ifdef CONFIG_MMU 91 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR) 92 return false; 93 #endif 94 return true; 95 } 96 97 static bool check_shared_memory(size_t alloc_size) 98 { 99 bool ret; 100 101 spin_lock_irq(&shared_memory_lock); 102 103 ret = __check_shared_memory(alloc_size); 104 105 spin_unlock_irq(&shared_memory_lock); 106 107 return ret; 108 } 109 110 static bool claim_shared_memory(size_t alloc_size) 111 { 112 spin_lock_irq(&shared_memory_lock); 113 114 if (!__check_shared_memory(alloc_size)) { 115 spin_unlock_irq(&shared_memory_lock); 116 return false; 117 } 118 119 shared_memory_amount += alloc_size; 120 121 spin_unlock_irq(&shared_memory_lock); 122 123 return true; 124 } 125 126 static void free_shared_memory(size_t alloc_size) 127 { 128 unsigned long flags; 129 130 spin_lock_irqsave(&shared_memory_lock, flags); 131 132 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) { 133 spin_unlock_irqrestore(&shared_memory_lock, flags); 134 DMCRIT("Memory usage accounting bug."); 135 return; 136 } 137 138 shared_memory_amount -= alloc_size; 139 140 spin_unlock_irqrestore(&shared_memory_lock, flags); 141 } 142 143 static void *dm_kvzalloc(size_t alloc_size, int node) 144 { 145 void *p; 146 147 if (!claim_shared_memory(alloc_size)) 148 return NULL; 149 150 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node); 151 if (p) 152 return p; 153 154 free_shared_memory(alloc_size); 155 156 return NULL; 157 } 158 159 static void dm_kvfree(void *ptr, size_t alloc_size) 160 { 161 if (!ptr) 162 return; 163 164 free_shared_memory(alloc_size); 165 166 kvfree(ptr); 167 } 168 169 static void dm_stat_free(struct rcu_head *head) 170 { 171 int cpu; 172 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head); 173 174 kfree(s->histogram_boundaries); 175 kfree(s->program_id); 176 kfree(s->aux_data); 177 for_each_possible_cpu(cpu) { 178 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size); 179 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size); 180 } 181 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size); 182 dm_kvfree(s, s->shared_alloc_size); 183 } 184 185 static int dm_stat_in_flight(struct dm_stat_shared *shared) 186 { 187 return atomic_read(&shared->in_flight[READ]) + 188 atomic_read(&shared->in_flight[WRITE]); 189 } 190 191 void dm_stats_init(struct dm_stats *stats) 192 { 193 int cpu; 194 struct dm_stats_last_position *last; 195 196 mutex_init(&stats->mutex); 197 INIT_LIST_HEAD(&stats->list); 198 stats->precise_timestamps = false; 199 stats->last = alloc_percpu(struct dm_stats_last_position); 200 for_each_possible_cpu(cpu) { 201 last = per_cpu_ptr(stats->last, cpu); 202 last->last_sector = (sector_t)ULLONG_MAX; 203 last->last_rw = UINT_MAX; 204 } 205 } 206 207 void dm_stats_cleanup(struct dm_stats *stats) 208 { 209 size_t ni; 210 struct dm_stat *s; 211 struct dm_stat_shared *shared; 212 213 while (!list_empty(&stats->list)) { 214 s = container_of(stats->list.next, struct dm_stat, list_entry); 215 list_del(&s->list_entry); 216 for (ni = 0; ni < s->n_entries; ni++) { 217 shared = &s->stat_shared[ni]; 218 if (WARN_ON(dm_stat_in_flight(shared))) { 219 DMCRIT("leaked in-flight counter at index %lu " 220 "(start %llu, end %llu, step %llu): reads %d, writes %d", 221 (unsigned long)ni, 222 (unsigned long long)s->start, 223 (unsigned long long)s->end, 224 (unsigned long long)s->step, 225 atomic_read(&shared->in_flight[READ]), 226 atomic_read(&shared->in_flight[WRITE])); 227 } 228 } 229 dm_stat_free(&s->rcu_head); 230 } 231 free_percpu(stats->last); 232 mutex_destroy(&stats->mutex); 233 } 234 235 static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats) 236 { 237 struct list_head *l; 238 struct dm_stat *tmp_s; 239 bool precise_timestamps = false; 240 241 list_for_each(l, &stats->list) { 242 tmp_s = container_of(l, struct dm_stat, list_entry); 243 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) { 244 precise_timestamps = true; 245 break; 246 } 247 } 248 stats->precise_timestamps = precise_timestamps; 249 } 250 251 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 252 sector_t step, unsigned stat_flags, 253 unsigned n_histogram_entries, 254 unsigned long long *histogram_boundaries, 255 const char *program_id, const char *aux_data, 256 void (*suspend_callback)(struct mapped_device *), 257 void (*resume_callback)(struct mapped_device *), 258 struct mapped_device *md) 259 { 260 struct list_head *l; 261 struct dm_stat *s, *tmp_s; 262 sector_t n_entries; 263 size_t ni; 264 size_t shared_alloc_size; 265 size_t percpu_alloc_size; 266 size_t histogram_alloc_size; 267 struct dm_stat_percpu *p; 268 int cpu; 269 int ret_id; 270 int r; 271 272 if (end < start || !step) 273 return -EINVAL; 274 275 n_entries = end - start; 276 if (dm_sector_div64(n_entries, step)) 277 n_entries++; 278 279 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1)) 280 return -EOVERFLOW; 281 282 shared_alloc_size = struct_size(s, stat_shared, n_entries); 283 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries) 284 return -EOVERFLOW; 285 286 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu); 287 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries) 288 return -EOVERFLOW; 289 290 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long); 291 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long)) 292 return -EOVERFLOW; 293 294 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size + 295 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size))) 296 return -ENOMEM; 297 298 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE); 299 if (!s) 300 return -ENOMEM; 301 302 s->stat_flags = stat_flags; 303 s->n_entries = n_entries; 304 s->start = start; 305 s->end = end; 306 s->step = step; 307 s->shared_alloc_size = shared_alloc_size; 308 s->percpu_alloc_size = percpu_alloc_size; 309 s->histogram_alloc_size = histogram_alloc_size; 310 311 s->n_histogram_entries = n_histogram_entries; 312 s->histogram_boundaries = kmemdup(histogram_boundaries, 313 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); 314 if (!s->histogram_boundaries) { 315 r = -ENOMEM; 316 goto out; 317 } 318 319 s->program_id = kstrdup(program_id, GFP_KERNEL); 320 if (!s->program_id) { 321 r = -ENOMEM; 322 goto out; 323 } 324 s->aux_data = kstrdup(aux_data, GFP_KERNEL); 325 if (!s->aux_data) { 326 r = -ENOMEM; 327 goto out; 328 } 329 330 for (ni = 0; ni < n_entries; ni++) { 331 atomic_set(&s->stat_shared[ni].in_flight[READ], 0); 332 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0); 333 } 334 335 if (s->n_histogram_entries) { 336 unsigned long long *hi; 337 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE); 338 if (!hi) { 339 r = -ENOMEM; 340 goto out; 341 } 342 for (ni = 0; ni < n_entries; ni++) { 343 s->stat_shared[ni].tmp.histogram = hi; 344 hi += s->n_histogram_entries + 1; 345 } 346 } 347 348 for_each_possible_cpu(cpu) { 349 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu)); 350 if (!p) { 351 r = -ENOMEM; 352 goto out; 353 } 354 s->stat_percpu[cpu] = p; 355 if (s->n_histogram_entries) { 356 unsigned long long *hi; 357 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu)); 358 if (!hi) { 359 r = -ENOMEM; 360 goto out; 361 } 362 for (ni = 0; ni < n_entries; ni++) { 363 p[ni].histogram = hi; 364 hi += s->n_histogram_entries + 1; 365 } 366 } 367 } 368 369 /* 370 * Suspend/resume to make sure there is no i/o in flight, 371 * so that newly created statistics will be exact. 372 * 373 * (note: we couldn't suspend earlier because we must not 374 * allocate memory while suspended) 375 */ 376 suspend_callback(md); 377 378 mutex_lock(&stats->mutex); 379 s->id = 0; 380 list_for_each(l, &stats->list) { 381 tmp_s = container_of(l, struct dm_stat, list_entry); 382 if (WARN_ON(tmp_s->id < s->id)) { 383 r = -EINVAL; 384 goto out_unlock_resume; 385 } 386 if (tmp_s->id > s->id) 387 break; 388 if (unlikely(s->id == INT_MAX)) { 389 r = -ENFILE; 390 goto out_unlock_resume; 391 } 392 s->id++; 393 } 394 ret_id = s->id; 395 list_add_tail_rcu(&s->list_entry, l); 396 397 dm_stats_recalc_precise_timestamps(stats); 398 399 mutex_unlock(&stats->mutex); 400 401 resume_callback(md); 402 403 return ret_id; 404 405 out_unlock_resume: 406 mutex_unlock(&stats->mutex); 407 resume_callback(md); 408 out: 409 dm_stat_free(&s->rcu_head); 410 return r; 411 } 412 413 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id) 414 { 415 struct dm_stat *s; 416 417 list_for_each_entry(s, &stats->list, list_entry) { 418 if (s->id > id) 419 break; 420 if (s->id == id) 421 return s; 422 } 423 424 return NULL; 425 } 426 427 static int dm_stats_delete(struct dm_stats *stats, int id) 428 { 429 struct dm_stat *s; 430 int cpu; 431 432 mutex_lock(&stats->mutex); 433 434 s = __dm_stats_find(stats, id); 435 if (!s) { 436 mutex_unlock(&stats->mutex); 437 return -ENOENT; 438 } 439 440 list_del_rcu(&s->list_entry); 441 442 dm_stats_recalc_precise_timestamps(stats); 443 444 mutex_unlock(&stats->mutex); 445 446 /* 447 * vfree can't be called from RCU callback 448 */ 449 for_each_possible_cpu(cpu) 450 if (is_vmalloc_addr(s->stat_percpu) || 451 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram)) 452 goto do_sync_free; 453 if (is_vmalloc_addr(s) || 454 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) { 455 do_sync_free: 456 synchronize_rcu_expedited(); 457 dm_stat_free(&s->rcu_head); 458 } else { 459 WRITE_ONCE(dm_stat_need_rcu_barrier, 1); 460 call_rcu(&s->rcu_head, dm_stat_free); 461 } 462 return 0; 463 } 464 465 static int dm_stats_list(struct dm_stats *stats, const char *program, 466 char *result, unsigned maxlen) 467 { 468 struct dm_stat *s; 469 sector_t len; 470 unsigned sz = 0; 471 472 /* 473 * Output format: 474 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data> 475 */ 476 477 mutex_lock(&stats->mutex); 478 list_for_each_entry(s, &stats->list, list_entry) { 479 if (!program || !strcmp(program, s->program_id)) { 480 len = s->end - s->start; 481 DMEMIT("%d: %llu+%llu %llu %s %s", s->id, 482 (unsigned long long)s->start, 483 (unsigned long long)len, 484 (unsigned long long)s->step, 485 s->program_id, 486 s->aux_data); 487 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 488 DMEMIT(" precise_timestamps"); 489 if (s->n_histogram_entries) { 490 unsigned i; 491 DMEMIT(" histogram:"); 492 for (i = 0; i < s->n_histogram_entries; i++) { 493 if (i) 494 DMEMIT(","); 495 DMEMIT("%llu", s->histogram_boundaries[i]); 496 } 497 } 498 DMEMIT("\n"); 499 } 500 } 501 mutex_unlock(&stats->mutex); 502 503 return 1; 504 } 505 506 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared, 507 struct dm_stat_percpu *p) 508 { 509 /* 510 * This is racy, but so is part_round_stats_single. 511 */ 512 unsigned long long now, difference; 513 unsigned in_flight_read, in_flight_write; 514 515 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS))) 516 now = jiffies; 517 else 518 now = ktime_to_ns(ktime_get()); 519 520 difference = now - shared->stamp; 521 if (!difference) 522 return; 523 524 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]); 525 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]); 526 if (in_flight_read) 527 p->io_ticks[READ] += difference; 528 if (in_flight_write) 529 p->io_ticks[WRITE] += difference; 530 if (in_flight_read + in_flight_write) { 531 p->io_ticks_total += difference; 532 p->time_in_queue += (in_flight_read + in_flight_write) * difference; 533 } 534 shared->stamp = now; 535 } 536 537 static void dm_stat_for_entry(struct dm_stat *s, size_t entry, 538 int idx, sector_t len, 539 struct dm_stats_aux *stats_aux, bool end, 540 unsigned long duration_jiffies) 541 { 542 struct dm_stat_shared *shared = &s->stat_shared[entry]; 543 struct dm_stat_percpu *p; 544 545 /* 546 * For strict correctness we should use local_irq_save/restore 547 * instead of preempt_disable/enable. 548 * 549 * preempt_disable/enable is racy if the driver finishes bios 550 * from non-interrupt context as well as from interrupt context 551 * or from more different interrupts. 552 * 553 * On 64-bit architectures the race only results in not counting some 554 * events, so it is acceptable. On 32-bit architectures the race could 555 * cause the counter going off by 2^32, so we need to do proper locking 556 * there. 557 * 558 * part_stat_lock()/part_stat_unlock() have this race too. 559 */ 560 #if BITS_PER_LONG == 32 561 unsigned long flags; 562 local_irq_save(flags); 563 #else 564 preempt_disable(); 565 #endif 566 p = &s->stat_percpu[smp_processor_id()][entry]; 567 568 if (!end) { 569 dm_stat_round(s, shared, p); 570 atomic_inc(&shared->in_flight[idx]); 571 } else { 572 unsigned long long duration; 573 dm_stat_round(s, shared, p); 574 atomic_dec(&shared->in_flight[idx]); 575 p->sectors[idx] += len; 576 p->ios[idx] += 1; 577 p->merges[idx] += stats_aux->merged; 578 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) { 579 p->ticks[idx] += duration_jiffies; 580 duration = jiffies_to_msecs(duration_jiffies); 581 } else { 582 p->ticks[idx] += stats_aux->duration_ns; 583 duration = stats_aux->duration_ns; 584 } 585 if (s->n_histogram_entries) { 586 unsigned lo = 0, hi = s->n_histogram_entries + 1; 587 while (lo + 1 < hi) { 588 unsigned mid = (lo + hi) / 2; 589 if (s->histogram_boundaries[mid - 1] > duration) { 590 hi = mid; 591 } else { 592 lo = mid; 593 } 594 595 } 596 p->histogram[lo]++; 597 } 598 } 599 600 #if BITS_PER_LONG == 32 601 local_irq_restore(flags); 602 #else 603 preempt_enable(); 604 #endif 605 } 606 607 static void __dm_stat_bio(struct dm_stat *s, int bi_rw, 608 sector_t bi_sector, sector_t end_sector, 609 bool end, unsigned long duration_jiffies, 610 struct dm_stats_aux *stats_aux) 611 { 612 sector_t rel_sector, offset, todo, fragment_len; 613 size_t entry; 614 615 if (end_sector <= s->start || bi_sector >= s->end) 616 return; 617 if (unlikely(bi_sector < s->start)) { 618 rel_sector = 0; 619 todo = end_sector - s->start; 620 } else { 621 rel_sector = bi_sector - s->start; 622 todo = end_sector - bi_sector; 623 } 624 if (unlikely(end_sector > s->end)) 625 todo -= (end_sector - s->end); 626 627 offset = dm_sector_div64(rel_sector, s->step); 628 entry = rel_sector; 629 do { 630 if (WARN_ON_ONCE(entry >= s->n_entries)) { 631 DMCRIT("Invalid area access in region id %d", s->id); 632 return; 633 } 634 fragment_len = todo; 635 if (fragment_len > s->step - offset) 636 fragment_len = s->step - offset; 637 dm_stat_for_entry(s, entry, bi_rw, fragment_len, 638 stats_aux, end, duration_jiffies); 639 todo -= fragment_len; 640 entry++; 641 offset = 0; 642 } while (unlikely(todo != 0)); 643 } 644 645 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, 646 sector_t bi_sector, unsigned bi_sectors, bool end, 647 unsigned long start_time, 648 struct dm_stats_aux *stats_aux) 649 { 650 struct dm_stat *s; 651 sector_t end_sector; 652 struct dm_stats_last_position *last; 653 bool got_precise_time; 654 unsigned long duration_jiffies = 0; 655 656 if (unlikely(!bi_sectors)) 657 return; 658 659 end_sector = bi_sector + bi_sectors; 660 661 if (!end) { 662 /* 663 * A race condition can at worst result in the merged flag being 664 * misrepresented, so we don't have to disable preemption here. 665 */ 666 last = raw_cpu_ptr(stats->last); 667 stats_aux->merged = 668 (bi_sector == (READ_ONCE(last->last_sector) && 669 ((bi_rw == WRITE) == 670 (READ_ONCE(last->last_rw) == WRITE)) 671 )); 672 WRITE_ONCE(last->last_sector, end_sector); 673 WRITE_ONCE(last->last_rw, bi_rw); 674 } else 675 duration_jiffies = jiffies - start_time; 676 677 rcu_read_lock(); 678 679 got_precise_time = false; 680 list_for_each_entry_rcu(s, &stats->list, list_entry) { 681 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) { 682 /* start (!end) duration_ns is set by DM core's alloc_io() */ 683 if (end) 684 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns; 685 got_precise_time = true; 686 } 687 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux); 688 } 689 690 rcu_read_unlock(); 691 } 692 693 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared, 694 struct dm_stat *s, size_t x) 695 { 696 int cpu; 697 struct dm_stat_percpu *p; 698 699 local_irq_disable(); 700 p = &s->stat_percpu[smp_processor_id()][x]; 701 dm_stat_round(s, shared, p); 702 local_irq_enable(); 703 704 shared->tmp.sectors[READ] = 0; 705 shared->tmp.sectors[WRITE] = 0; 706 shared->tmp.ios[READ] = 0; 707 shared->tmp.ios[WRITE] = 0; 708 shared->tmp.merges[READ] = 0; 709 shared->tmp.merges[WRITE] = 0; 710 shared->tmp.ticks[READ] = 0; 711 shared->tmp.ticks[WRITE] = 0; 712 shared->tmp.io_ticks[READ] = 0; 713 shared->tmp.io_ticks[WRITE] = 0; 714 shared->tmp.io_ticks_total = 0; 715 shared->tmp.time_in_queue = 0; 716 717 if (s->n_histogram_entries) 718 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long)); 719 720 for_each_possible_cpu(cpu) { 721 p = &s->stat_percpu[cpu][x]; 722 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]); 723 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]); 724 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]); 725 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]); 726 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]); 727 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]); 728 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]); 729 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]); 730 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]); 731 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]); 732 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total); 733 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue); 734 if (s->n_histogram_entries) { 735 unsigned i; 736 for (i = 0; i < s->n_histogram_entries + 1; i++) 737 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]); 738 } 739 } 740 } 741 742 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end, 743 bool init_tmp_percpu_totals) 744 { 745 size_t x; 746 struct dm_stat_shared *shared; 747 struct dm_stat_percpu *p; 748 749 for (x = idx_start; x < idx_end; x++) { 750 shared = &s->stat_shared[x]; 751 if (init_tmp_percpu_totals) 752 __dm_stat_init_temporary_percpu_totals(shared, s, x); 753 local_irq_disable(); 754 p = &s->stat_percpu[smp_processor_id()][x]; 755 p->sectors[READ] -= shared->tmp.sectors[READ]; 756 p->sectors[WRITE] -= shared->tmp.sectors[WRITE]; 757 p->ios[READ] -= shared->tmp.ios[READ]; 758 p->ios[WRITE] -= shared->tmp.ios[WRITE]; 759 p->merges[READ] -= shared->tmp.merges[READ]; 760 p->merges[WRITE] -= shared->tmp.merges[WRITE]; 761 p->ticks[READ] -= shared->tmp.ticks[READ]; 762 p->ticks[WRITE] -= shared->tmp.ticks[WRITE]; 763 p->io_ticks[READ] -= shared->tmp.io_ticks[READ]; 764 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE]; 765 p->io_ticks_total -= shared->tmp.io_ticks_total; 766 p->time_in_queue -= shared->tmp.time_in_queue; 767 local_irq_enable(); 768 if (s->n_histogram_entries) { 769 unsigned i; 770 for (i = 0; i < s->n_histogram_entries + 1; i++) { 771 local_irq_disable(); 772 p = &s->stat_percpu[smp_processor_id()][x]; 773 p->histogram[i] -= shared->tmp.histogram[i]; 774 local_irq_enable(); 775 } 776 } 777 } 778 } 779 780 static int dm_stats_clear(struct dm_stats *stats, int id) 781 { 782 struct dm_stat *s; 783 784 mutex_lock(&stats->mutex); 785 786 s = __dm_stats_find(stats, id); 787 if (!s) { 788 mutex_unlock(&stats->mutex); 789 return -ENOENT; 790 } 791 792 __dm_stat_clear(s, 0, s->n_entries, true); 793 794 mutex_unlock(&stats->mutex); 795 796 return 1; 797 } 798 799 /* 800 * This is like jiffies_to_msec, but works for 64-bit values. 801 */ 802 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j) 803 { 804 unsigned long long result; 805 unsigned mult; 806 807 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 808 return j; 809 810 result = 0; 811 if (j) 812 result = jiffies_to_msecs(j & 0x3fffff); 813 if (j >= 1 << 22) { 814 mult = jiffies_to_msecs(1 << 22); 815 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff); 816 } 817 if (j >= 1ULL << 44) 818 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44); 819 820 return result; 821 } 822 823 static int dm_stats_print(struct dm_stats *stats, int id, 824 size_t idx_start, size_t idx_len, 825 bool clear, char *result, unsigned maxlen) 826 { 827 unsigned sz = 0; 828 struct dm_stat *s; 829 size_t x; 830 sector_t start, end, step; 831 size_t idx_end; 832 struct dm_stat_shared *shared; 833 834 /* 835 * Output format: 836 * <start_sector>+<length> counters 837 */ 838 839 mutex_lock(&stats->mutex); 840 841 s = __dm_stats_find(stats, id); 842 if (!s) { 843 mutex_unlock(&stats->mutex); 844 return -ENOENT; 845 } 846 847 idx_end = idx_start + idx_len; 848 if (idx_end < idx_start || 849 idx_end > s->n_entries) 850 idx_end = s->n_entries; 851 852 if (idx_start > idx_end) 853 idx_start = idx_end; 854 855 step = s->step; 856 start = s->start + (step * idx_start); 857 858 for (x = idx_start; x < idx_end; x++, start = end) { 859 shared = &s->stat_shared[x]; 860 end = start + step; 861 if (unlikely(end > s->end)) 862 end = s->end; 863 864 __dm_stat_init_temporary_percpu_totals(shared, s, x); 865 866 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu", 867 (unsigned long long)start, 868 (unsigned long long)step, 869 shared->tmp.ios[READ], 870 shared->tmp.merges[READ], 871 shared->tmp.sectors[READ], 872 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]), 873 shared->tmp.ios[WRITE], 874 shared->tmp.merges[WRITE], 875 shared->tmp.sectors[WRITE], 876 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]), 877 dm_stat_in_flight(shared), 878 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total), 879 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue), 880 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]), 881 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE])); 882 if (s->n_histogram_entries) { 883 unsigned i; 884 for (i = 0; i < s->n_histogram_entries + 1; i++) { 885 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]); 886 } 887 } 888 DMEMIT("\n"); 889 890 if (unlikely(sz + 1 >= maxlen)) 891 goto buffer_overflow; 892 } 893 894 if (clear) 895 __dm_stat_clear(s, idx_start, idx_end, false); 896 897 buffer_overflow: 898 mutex_unlock(&stats->mutex); 899 900 return 1; 901 } 902 903 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data) 904 { 905 struct dm_stat *s; 906 const char *new_aux_data; 907 908 mutex_lock(&stats->mutex); 909 910 s = __dm_stats_find(stats, id); 911 if (!s) { 912 mutex_unlock(&stats->mutex); 913 return -ENOENT; 914 } 915 916 new_aux_data = kstrdup(aux_data, GFP_KERNEL); 917 if (!new_aux_data) { 918 mutex_unlock(&stats->mutex); 919 return -ENOMEM; 920 } 921 922 kfree(s->aux_data); 923 s->aux_data = new_aux_data; 924 925 mutex_unlock(&stats->mutex); 926 927 return 0; 928 } 929 930 static int parse_histogram(const char *h, unsigned *n_histogram_entries, 931 unsigned long long **histogram_boundaries) 932 { 933 const char *q; 934 unsigned n; 935 unsigned long long last; 936 937 *n_histogram_entries = 1; 938 for (q = h; *q; q++) 939 if (*q == ',') 940 (*n_histogram_entries)++; 941 942 *histogram_boundaries = kmalloc_array(*n_histogram_entries, 943 sizeof(unsigned long long), 944 GFP_KERNEL); 945 if (!*histogram_boundaries) 946 return -ENOMEM; 947 948 n = 0; 949 last = 0; 950 while (1) { 951 unsigned long long hi; 952 int s; 953 char ch; 954 s = sscanf(h, "%llu%c", &hi, &ch); 955 if (!s || (s == 2 && ch != ',')) 956 return -EINVAL; 957 if (hi <= last) 958 return -EINVAL; 959 last = hi; 960 (*histogram_boundaries)[n] = hi; 961 if (s == 1) 962 return 0; 963 h = strchr(h, ',') + 1; 964 n++; 965 } 966 } 967 968 static int message_stats_create(struct mapped_device *md, 969 unsigned argc, char **argv, 970 char *result, unsigned maxlen) 971 { 972 int r; 973 int id; 974 char dummy; 975 unsigned long long start, end, len, step; 976 unsigned divisor; 977 const char *program_id, *aux_data; 978 unsigned stat_flags = 0; 979 980 unsigned n_histogram_entries = 0; 981 unsigned long long *histogram_boundaries = NULL; 982 983 struct dm_arg_set as, as_backup; 984 const char *a; 985 unsigned feature_args; 986 987 /* 988 * Input format: 989 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]] 990 */ 991 992 if (argc < 3) 993 goto ret_einval; 994 995 as.argc = argc; 996 as.argv = argv; 997 dm_consume_args(&as, 1); 998 999 a = dm_shift_arg(&as); 1000 if (!strcmp(a, "-")) { 1001 start = 0; 1002 len = dm_get_size(md); 1003 if (!len) 1004 len = 1; 1005 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 || 1006 start != (sector_t)start || len != (sector_t)len) 1007 goto ret_einval; 1008 1009 end = start + len; 1010 if (start >= end) 1011 goto ret_einval; 1012 1013 a = dm_shift_arg(&as); 1014 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) { 1015 if (!divisor) 1016 return -EINVAL; 1017 step = end - start; 1018 if (do_div(step, divisor)) 1019 step++; 1020 if (!step) 1021 step = 1; 1022 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 || 1023 step != (sector_t)step || !step) 1024 goto ret_einval; 1025 1026 as_backup = as; 1027 a = dm_shift_arg(&as); 1028 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) { 1029 while (feature_args--) { 1030 a = dm_shift_arg(&as); 1031 if (!a) 1032 goto ret_einval; 1033 if (!strcasecmp(a, "precise_timestamps")) 1034 stat_flags |= STAT_PRECISE_TIMESTAMPS; 1035 else if (!strncasecmp(a, "histogram:", 10)) { 1036 if (n_histogram_entries) 1037 goto ret_einval; 1038 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries))) 1039 goto ret; 1040 } else 1041 goto ret_einval; 1042 } 1043 } else { 1044 as = as_backup; 1045 } 1046 1047 program_id = "-"; 1048 aux_data = "-"; 1049 1050 a = dm_shift_arg(&as); 1051 if (a) 1052 program_id = a; 1053 1054 a = dm_shift_arg(&as); 1055 if (a) 1056 aux_data = a; 1057 1058 if (as.argc) 1059 goto ret_einval; 1060 1061 /* 1062 * If a buffer overflow happens after we created the region, 1063 * it's too late (the userspace would retry with a larger 1064 * buffer, but the region id that caused the overflow is already 1065 * leaked). So we must detect buffer overflow in advance. 1066 */ 1067 snprintf(result, maxlen, "%d", INT_MAX); 1068 if (dm_message_test_buffer_overflow(result, maxlen)) { 1069 r = 1; 1070 goto ret; 1071 } 1072 1073 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, 1074 n_histogram_entries, histogram_boundaries, program_id, aux_data, 1075 dm_internal_suspend_fast, dm_internal_resume_fast, md); 1076 if (id < 0) { 1077 r = id; 1078 goto ret; 1079 } 1080 1081 snprintf(result, maxlen, "%d", id); 1082 1083 r = 1; 1084 goto ret; 1085 1086 ret_einval: 1087 r = -EINVAL; 1088 ret: 1089 kfree(histogram_boundaries); 1090 return r; 1091 } 1092 1093 static int message_stats_delete(struct mapped_device *md, 1094 unsigned argc, char **argv) 1095 { 1096 int id; 1097 char dummy; 1098 1099 if (argc != 2) 1100 return -EINVAL; 1101 1102 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1103 return -EINVAL; 1104 1105 return dm_stats_delete(dm_get_stats(md), id); 1106 } 1107 1108 static int message_stats_clear(struct mapped_device *md, 1109 unsigned argc, char **argv) 1110 { 1111 int id; 1112 char dummy; 1113 1114 if (argc != 2) 1115 return -EINVAL; 1116 1117 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1118 return -EINVAL; 1119 1120 return dm_stats_clear(dm_get_stats(md), id); 1121 } 1122 1123 static int message_stats_list(struct mapped_device *md, 1124 unsigned argc, char **argv, 1125 char *result, unsigned maxlen) 1126 { 1127 int r; 1128 const char *program = NULL; 1129 1130 if (argc < 1 || argc > 2) 1131 return -EINVAL; 1132 1133 if (argc > 1) { 1134 program = kstrdup(argv[1], GFP_KERNEL); 1135 if (!program) 1136 return -ENOMEM; 1137 } 1138 1139 r = dm_stats_list(dm_get_stats(md), program, result, maxlen); 1140 1141 kfree(program); 1142 1143 return r; 1144 } 1145 1146 static int message_stats_print(struct mapped_device *md, 1147 unsigned argc, char **argv, bool clear, 1148 char *result, unsigned maxlen) 1149 { 1150 int id; 1151 char dummy; 1152 unsigned long idx_start = 0, idx_len = ULONG_MAX; 1153 1154 if (argc != 2 && argc != 4) 1155 return -EINVAL; 1156 1157 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1158 return -EINVAL; 1159 1160 if (argc > 3) { 1161 if (strcmp(argv[2], "-") && 1162 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1) 1163 return -EINVAL; 1164 if (strcmp(argv[3], "-") && 1165 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1) 1166 return -EINVAL; 1167 } 1168 1169 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear, 1170 result, maxlen); 1171 } 1172 1173 static int message_stats_set_aux(struct mapped_device *md, 1174 unsigned argc, char **argv) 1175 { 1176 int id; 1177 char dummy; 1178 1179 if (argc != 3) 1180 return -EINVAL; 1181 1182 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1183 return -EINVAL; 1184 1185 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]); 1186 } 1187 1188 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv, 1189 char *result, unsigned maxlen) 1190 { 1191 int r; 1192 1193 /* All messages here must start with '@' */ 1194 if (!strcasecmp(argv[0], "@stats_create")) 1195 r = message_stats_create(md, argc, argv, result, maxlen); 1196 else if (!strcasecmp(argv[0], "@stats_delete")) 1197 r = message_stats_delete(md, argc, argv); 1198 else if (!strcasecmp(argv[0], "@stats_clear")) 1199 r = message_stats_clear(md, argc, argv); 1200 else if (!strcasecmp(argv[0], "@stats_list")) 1201 r = message_stats_list(md, argc, argv, result, maxlen); 1202 else if (!strcasecmp(argv[0], "@stats_print")) 1203 r = message_stats_print(md, argc, argv, false, result, maxlen); 1204 else if (!strcasecmp(argv[0], "@stats_print_clear")) 1205 r = message_stats_print(md, argc, argv, true, result, maxlen); 1206 else if (!strcasecmp(argv[0], "@stats_set_aux")) 1207 r = message_stats_set_aux(md, argc, argv); 1208 else 1209 return 2; /* this wasn't a stats message */ 1210 1211 if (r == -EINVAL) 1212 DMWARN("Invalid parameters for message %s", argv[0]); 1213 1214 return r; 1215 } 1216 1217 int __init dm_statistics_init(void) 1218 { 1219 shared_memory_amount = 0; 1220 dm_stat_need_rcu_barrier = 0; 1221 return 0; 1222 } 1223 1224 void dm_statistics_exit(void) 1225 { 1226 if (dm_stat_need_rcu_barrier) 1227 rcu_barrier(); 1228 if (WARN_ON(shared_memory_amount)) 1229 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount); 1230 } 1231 1232 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO); 1233 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics"); 1234