1266 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2#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 19static int dm_stat_need_rcu_barrier;20 21/*22 * Using 64-bit values to avoid overflow (which is a23 * problem that block/genhd.c's IO accounting has).24 */25struct 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 36struct dm_stat_shared {37 atomic_t in_flight[2];38 unsigned long long stamp;39 struct dm_stat_percpu tmp;40};41 42struct dm_stat {43 struct list_head list_entry;44 int id;45 unsigned int stat_flags;46 size_t n_entries;47 sector_t start;48 sector_t end;49 sector_t step;50 unsigned int 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[] __counted_by(n_entries);60};61 62#define STAT_PRECISE_TIMESTAMPS 163 64struct dm_stats_last_position {65 sector_t last_sector;66 unsigned int last_rw;67};68 69#define DM_STAT_MAX_ENTRIES 838860870#define DM_STAT_MAX_HISTOGRAM_ENTRIES 13421772871 72/*73 * A typo on the command line could possibly make the kernel run out of memory74 * and crash. To prevent the crash we account all used memory. We fail if we75 * exhaust 1/4 of all memory or 1/2 of vmalloc space.76 */77#define DM_STATS_MEMORY_FACTOR 478#define DM_STATS_VMALLOC_FACTOR 279 80static DEFINE_SPINLOCK(shared_memory_lock);81 82static unsigned long shared_memory_amount;83 84static bool __check_shared_memory(size_t alloc_size)85{86 size_t a;87 88 a = shared_memory_amount + alloc_size;89 if (a < shared_memory_amount)90 return false;91 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)92 return false;93#ifdef CONFIG_MMU94 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)95 return false;96#endif97 return true;98}99 100static bool check_shared_memory(size_t alloc_size)101{102 bool ret;103 104 spin_lock_irq(&shared_memory_lock);105 106 ret = __check_shared_memory(alloc_size);107 108 spin_unlock_irq(&shared_memory_lock);109 110 return ret;111}112 113static bool claim_shared_memory(size_t alloc_size)114{115 spin_lock_irq(&shared_memory_lock);116 117 if (!__check_shared_memory(alloc_size)) {118 spin_unlock_irq(&shared_memory_lock);119 return false;120 }121 122 shared_memory_amount += alloc_size;123 124 spin_unlock_irq(&shared_memory_lock);125 126 return true;127}128 129static void free_shared_memory(size_t alloc_size)130{131 unsigned long flags;132 133 spin_lock_irqsave(&shared_memory_lock, flags);134 135 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {136 spin_unlock_irqrestore(&shared_memory_lock, flags);137 DMCRIT("Memory usage accounting bug.");138 return;139 }140 141 shared_memory_amount -= alloc_size;142 143 spin_unlock_irqrestore(&shared_memory_lock, flags);144}145 146static void *dm_kvzalloc(size_t alloc_size, int node)147{148 void *p;149 150 if (!claim_shared_memory(alloc_size))151 return NULL;152 153 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);154 if (p)155 return p;156 157 free_shared_memory(alloc_size);158 159 return NULL;160}161 162static void dm_kvfree(void *ptr, size_t alloc_size)163{164 if (!ptr)165 return;166 167 free_shared_memory(alloc_size);168 169 kvfree(ptr);170}171 172static void dm_stat_free(struct rcu_head *head)173{174 int cpu;175 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);176 177 kfree(s->histogram_boundaries);178 kfree(s->program_id);179 kfree(s->aux_data);180 for_each_possible_cpu(cpu) {181 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);182 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);183 }184 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);185 dm_kvfree(s, s->shared_alloc_size);186}187 188static int dm_stat_in_flight(struct dm_stat_shared *shared)189{190 return atomic_read(&shared->in_flight[READ]) +191 atomic_read(&shared->in_flight[WRITE]);192}193 194int dm_stats_init(struct dm_stats *stats)195{196 int cpu;197 struct dm_stats_last_position *last;198 199 mutex_init(&stats->mutex);200 INIT_LIST_HEAD(&stats->list);201 stats->precise_timestamps = false;202 stats->last = alloc_percpu(struct dm_stats_last_position);203 if (!stats->last)204 return -ENOMEM;205 206 for_each_possible_cpu(cpu) {207 last = per_cpu_ptr(stats->last, cpu);208 last->last_sector = (sector_t)ULLONG_MAX;209 last->last_rw = UINT_MAX;210 }211 212 return 0;213}214 215void dm_stats_cleanup(struct dm_stats *stats)216{217 size_t ni;218 struct dm_stat *s;219 struct dm_stat_shared *shared;220 221 while (!list_empty(&stats->list)) {222 s = container_of(stats->list.next, struct dm_stat, list_entry);223 list_del(&s->list_entry);224 for (ni = 0; ni < s->n_entries; ni++) {225 shared = &s->stat_shared[ni];226 if (WARN_ON(dm_stat_in_flight(shared))) {227 DMCRIT("leaked in-flight counter at index %lu "228 "(start %llu, end %llu, step %llu): reads %d, writes %d",229 (unsigned long)ni,230 (unsigned long long)s->start,231 (unsigned long long)s->end,232 (unsigned long long)s->step,233 atomic_read(&shared->in_flight[READ]),234 atomic_read(&shared->in_flight[WRITE]));235 }236 cond_resched();237 }238 dm_stat_free(&s->rcu_head);239 }240 free_percpu(stats->last);241 mutex_destroy(&stats->mutex);242}243 244static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)245{246 struct list_head *l;247 struct dm_stat *tmp_s;248 bool precise_timestamps = false;249 250 list_for_each(l, &stats->list) {251 tmp_s = container_of(l, struct dm_stat, list_entry);252 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {253 precise_timestamps = true;254 break;255 }256 }257 stats->precise_timestamps = precise_timestamps;258}259 260static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,261 sector_t step, unsigned int stat_flags,262 unsigned int n_histogram_entries,263 unsigned long long *histogram_boundaries,264 const char *program_id, const char *aux_data,265 void (*suspend_callback)(struct mapped_device *),266 void (*resume_callback)(struct mapped_device *),267 struct mapped_device *md)268{269 struct list_head *l;270 struct dm_stat *s, *tmp_s;271 sector_t n_entries;272 size_t ni;273 size_t shared_alloc_size;274 size_t percpu_alloc_size;275 size_t histogram_alloc_size;276 struct dm_stat_percpu *p;277 int cpu;278 int ret_id;279 int r;280 281 if (end < start || !step)282 return -EINVAL;283 284 n_entries = end - start;285 if (dm_sector_div64(n_entries, step))286 n_entries++;287 288 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))289 return -EOVERFLOW;290 291 if (n_entries > DM_STAT_MAX_ENTRIES)292 return -EOVERFLOW;293 294 shared_alloc_size = struct_size(s, stat_shared, n_entries);295 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)296 return -EOVERFLOW;297 298 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);299 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)300 return -EOVERFLOW;301 302 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);303 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))304 return -EOVERFLOW;305 306 if ((n_histogram_entries + 1) * (size_t)n_entries > DM_STAT_MAX_HISTOGRAM_ENTRIES)307 return -EOVERFLOW;308 309 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +310 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))311 return -ENOMEM;312 313 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);314 if (!s)315 return -ENOMEM;316 317 s->stat_flags = stat_flags;318 s->n_entries = n_entries;319 s->start = start;320 s->end = end;321 s->step = step;322 s->shared_alloc_size = shared_alloc_size;323 s->percpu_alloc_size = percpu_alloc_size;324 s->histogram_alloc_size = histogram_alloc_size;325 326 s->n_histogram_entries = n_histogram_entries;327 s->histogram_boundaries = kmemdup(histogram_boundaries,328 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);329 if (!s->histogram_boundaries) {330 r = -ENOMEM;331 goto out;332 }333 334 s->program_id = kstrdup(program_id, GFP_KERNEL);335 if (!s->program_id) {336 r = -ENOMEM;337 goto out;338 }339 s->aux_data = kstrdup(aux_data, GFP_KERNEL);340 if (!s->aux_data) {341 r = -ENOMEM;342 goto out;343 }344 345 for (ni = 0; ni < n_entries; ni++) {346 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);347 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);348 cond_resched();349 }350 351 if (s->n_histogram_entries) {352 unsigned long long *hi;353 354 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);355 if (!hi) {356 r = -ENOMEM;357 goto out;358 }359 for (ni = 0; ni < n_entries; ni++) {360 s->stat_shared[ni].tmp.histogram = hi;361 hi += s->n_histogram_entries + 1;362 cond_resched();363 }364 }365 366 for_each_possible_cpu(cpu) {367 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));368 if (!p) {369 r = -ENOMEM;370 goto out;371 }372 s->stat_percpu[cpu] = p;373 if (s->n_histogram_entries) {374 unsigned long long *hi;375 376 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));377 if (!hi) {378 r = -ENOMEM;379 goto out;380 }381 for (ni = 0; ni < n_entries; ni++) {382 p[ni].histogram = hi;383 hi += s->n_histogram_entries + 1;384 cond_resched();385 }386 }387 }388 389 /*390 * Suspend/resume to make sure there is no i/o in flight,391 * so that newly created statistics will be exact.392 *393 * (note: we couldn't suspend earlier because we must not394 * allocate memory while suspended)395 */396 suspend_callback(md);397 398 mutex_lock(&stats->mutex);399 s->id = 0;400 list_for_each(l, &stats->list) {401 tmp_s = container_of(l, struct dm_stat, list_entry);402 if (WARN_ON(tmp_s->id < s->id)) {403 r = -EINVAL;404 goto out_unlock_resume;405 }406 if (tmp_s->id > s->id)407 break;408 if (unlikely(s->id == INT_MAX)) {409 r = -ENFILE;410 goto out_unlock_resume;411 }412 s->id++;413 }414 ret_id = s->id;415 list_add_tail_rcu(&s->list_entry, l);416 417 dm_stats_recalc_precise_timestamps(stats);418 419 if (!static_key_enabled(&stats_enabled.key))420 static_branch_enable(&stats_enabled);421 422 mutex_unlock(&stats->mutex);423 424 resume_callback(md);425 426 return ret_id;427 428out_unlock_resume:429 mutex_unlock(&stats->mutex);430 resume_callback(md);431out:432 dm_stat_free(&s->rcu_head);433 return r;434}435 436static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)437{438 struct dm_stat *s;439 440 list_for_each_entry(s, &stats->list, list_entry) {441 if (s->id > id)442 break;443 if (s->id == id)444 return s;445 }446 447 return NULL;448}449 450static int dm_stats_delete(struct dm_stats *stats, int id)451{452 struct dm_stat *s;453 int cpu;454 455 mutex_lock(&stats->mutex);456 457 s = __dm_stats_find(stats, id);458 if (!s) {459 mutex_unlock(&stats->mutex);460 return -ENOENT;461 }462 463 list_del_rcu(&s->list_entry);464 465 dm_stats_recalc_precise_timestamps(stats);466 467 mutex_unlock(&stats->mutex);468 469 /*470 * vfree can't be called from RCU callback471 */472 for_each_possible_cpu(cpu)473 if (is_vmalloc_addr(s->stat_percpu) ||474 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))475 goto do_sync_free;476 if (is_vmalloc_addr(s) ||477 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {478do_sync_free:479 synchronize_rcu_expedited();480 dm_stat_free(&s->rcu_head);481 } else {482 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);483 call_rcu(&s->rcu_head, dm_stat_free);484 }485 return 0;486}487 488static int dm_stats_list(struct dm_stats *stats, const char *program,489 char *result, unsigned int maxlen)490{491 struct dm_stat *s;492 sector_t len;493 unsigned int sz = 0;494 495 /*496 * Output format:497 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>498 */499 500 mutex_lock(&stats->mutex);501 list_for_each_entry(s, &stats->list, list_entry) {502 if (!program || !strcmp(program, s->program_id)) {503 len = s->end - s->start;504 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,505 (unsigned long long)s->start,506 (unsigned long long)len,507 (unsigned long long)s->step,508 s->program_id,509 s->aux_data);510 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)511 DMEMIT(" precise_timestamps");512 if (s->n_histogram_entries) {513 unsigned int i;514 515 DMEMIT(" histogram:");516 for (i = 0; i < s->n_histogram_entries; i++) {517 if (i)518 DMEMIT(",");519 DMEMIT("%llu", s->histogram_boundaries[i]);520 }521 }522 DMEMIT("\n");523 }524 cond_resched();525 }526 mutex_unlock(&stats->mutex);527 528 return 1;529}530 531static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,532 struct dm_stat_percpu *p)533{534 /*535 * This is racy, but so is part_round_stats_single.536 */537 unsigned long long now, difference;538 unsigned int in_flight_read, in_flight_write;539 540 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))541 now = jiffies;542 else543 now = ktime_to_ns(ktime_get());544 545 difference = now - shared->stamp;546 if (!difference)547 return;548 549 in_flight_read = (unsigned int)atomic_read(&shared->in_flight[READ]);550 in_flight_write = (unsigned int)atomic_read(&shared->in_flight[WRITE]);551 if (in_flight_read)552 p->io_ticks[READ] += difference;553 if (in_flight_write)554 p->io_ticks[WRITE] += difference;555 if (in_flight_read + in_flight_write) {556 p->io_ticks_total += difference;557 p->time_in_queue += (in_flight_read + in_flight_write) * difference;558 }559 shared->stamp = now;560}561 562static void dm_stat_for_entry(struct dm_stat *s, size_t entry,563 int idx, sector_t len,564 struct dm_stats_aux *stats_aux, bool end,565 unsigned long duration_jiffies)566{567 struct dm_stat_shared *shared = &s->stat_shared[entry];568 struct dm_stat_percpu *p;569 570 /*571 * For strict correctness we should use local_irq_save/restore572 * instead of preempt_disable/enable.573 *574 * preempt_disable/enable is racy if the driver finishes bios575 * from non-interrupt context as well as from interrupt context576 * or from more different interrupts.577 *578 * On 64-bit architectures the race only results in not counting some579 * events, so it is acceptable. On 32-bit architectures the race could580 * cause the counter going off by 2^32, so we need to do proper locking581 * there.582 *583 * part_stat_lock()/part_stat_unlock() have this race too.584 */585#if BITS_PER_LONG == 32586 unsigned long flags;587 588 local_irq_save(flags);589#else590 preempt_disable();591#endif592 p = &s->stat_percpu[smp_processor_id()][entry];593 594 if (!end) {595 dm_stat_round(s, shared, p);596 atomic_inc(&shared->in_flight[idx]);597 } else {598 unsigned long long duration;599 600 dm_stat_round(s, shared, p);601 atomic_dec(&shared->in_flight[idx]);602 p->sectors[idx] += len;603 p->ios[idx] += 1;604 p->merges[idx] += stats_aux->merged;605 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {606 p->ticks[idx] += duration_jiffies;607 duration = jiffies_to_msecs(duration_jiffies);608 } else {609 p->ticks[idx] += stats_aux->duration_ns;610 duration = stats_aux->duration_ns;611 }612 if (s->n_histogram_entries) {613 unsigned int lo = 0, hi = s->n_histogram_entries + 1;614 615 while (lo + 1 < hi) {616 unsigned int mid = (lo + hi) / 2;617 618 if (s->histogram_boundaries[mid - 1] > duration)619 hi = mid;620 else621 lo = mid;622 }623 p->histogram[lo]++;624 }625 }626 627#if BITS_PER_LONG == 32628 local_irq_restore(flags);629#else630 preempt_enable();631#endif632}633 634static void __dm_stat_bio(struct dm_stat *s, int bi_rw,635 sector_t bi_sector, sector_t end_sector,636 bool end, unsigned long duration_jiffies,637 struct dm_stats_aux *stats_aux)638{639 sector_t rel_sector, offset, todo, fragment_len;640 size_t entry;641 642 if (end_sector <= s->start || bi_sector >= s->end)643 return;644 if (unlikely(bi_sector < s->start)) {645 rel_sector = 0;646 todo = end_sector - s->start;647 } else {648 rel_sector = bi_sector - s->start;649 todo = end_sector - bi_sector;650 }651 if (unlikely(end_sector > s->end))652 todo -= (end_sector - s->end);653 654 offset = dm_sector_div64(rel_sector, s->step);655 entry = rel_sector;656 do {657 if (WARN_ON_ONCE(entry >= s->n_entries)) {658 DMCRIT("Invalid area access in region id %d", s->id);659 return;660 }661 fragment_len = todo;662 if (fragment_len > s->step - offset)663 fragment_len = s->step - offset;664 dm_stat_for_entry(s, entry, bi_rw, fragment_len,665 stats_aux, end, duration_jiffies);666 todo -= fragment_len;667 entry++;668 offset = 0;669 } while (unlikely(todo != 0));670}671 672void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,673 sector_t bi_sector, unsigned int bi_sectors, bool end,674 unsigned long start_time,675 struct dm_stats_aux *stats_aux)676{677 struct dm_stat *s;678 sector_t end_sector;679 struct dm_stats_last_position *last;680 bool got_precise_time;681 unsigned long duration_jiffies = 0;682 683 if (unlikely(!bi_sectors))684 return;685 686 end_sector = bi_sector + bi_sectors;687 688 if (!end) {689 /*690 * A race condition can at worst result in the merged flag being691 * misrepresented, so we don't have to disable preemption here.692 */693 last = raw_cpu_ptr(stats->last);694 stats_aux->merged =695 (bi_sector == (READ_ONCE(last->last_sector) &&696 ((bi_rw == WRITE) ==697 (READ_ONCE(last->last_rw) == WRITE))698 ));699 WRITE_ONCE(last->last_sector, end_sector);700 WRITE_ONCE(last->last_rw, bi_rw);701 } else702 duration_jiffies = jiffies - start_time;703 704 rcu_read_lock();705 706 got_precise_time = false;707 list_for_each_entry_rcu(s, &stats->list, list_entry) {708 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {709 /* start (!end) duration_ns is set by DM core's alloc_io() */710 if (end)711 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;712 got_precise_time = true;713 }714 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);715 }716 717 rcu_read_unlock();718}719 720static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,721 struct dm_stat *s, size_t x)722{723 int cpu;724 struct dm_stat_percpu *p;725 726 local_irq_disable();727 p = &s->stat_percpu[smp_processor_id()][x];728 dm_stat_round(s, shared, p);729 local_irq_enable();730 731 shared->tmp.sectors[READ] = 0;732 shared->tmp.sectors[WRITE] = 0;733 shared->tmp.ios[READ] = 0;734 shared->tmp.ios[WRITE] = 0;735 shared->tmp.merges[READ] = 0;736 shared->tmp.merges[WRITE] = 0;737 shared->tmp.ticks[READ] = 0;738 shared->tmp.ticks[WRITE] = 0;739 shared->tmp.io_ticks[READ] = 0;740 shared->tmp.io_ticks[WRITE] = 0;741 shared->tmp.io_ticks_total = 0;742 shared->tmp.time_in_queue = 0;743 744 if (s->n_histogram_entries)745 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));746 747 for_each_possible_cpu(cpu) {748 p = &s->stat_percpu[cpu][x];749 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);750 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);751 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);752 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);753 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);754 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);755 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);756 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);757 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);758 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);759 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);760 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);761 if (s->n_histogram_entries) {762 unsigned int i;763 764 for (i = 0; i < s->n_histogram_entries + 1; i++)765 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);766 }767 }768}769 770static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,771 bool init_tmp_percpu_totals)772{773 size_t x;774 struct dm_stat_shared *shared;775 struct dm_stat_percpu *p;776 777 for (x = idx_start; x < idx_end; x++) {778 shared = &s->stat_shared[x];779 if (init_tmp_percpu_totals)780 __dm_stat_init_temporary_percpu_totals(shared, s, x);781 local_irq_disable();782 p = &s->stat_percpu[smp_processor_id()][x];783 p->sectors[READ] -= shared->tmp.sectors[READ];784 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];785 p->ios[READ] -= shared->tmp.ios[READ];786 p->ios[WRITE] -= shared->tmp.ios[WRITE];787 p->merges[READ] -= shared->tmp.merges[READ];788 p->merges[WRITE] -= shared->tmp.merges[WRITE];789 p->ticks[READ] -= shared->tmp.ticks[READ];790 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];791 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];792 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];793 p->io_ticks_total -= shared->tmp.io_ticks_total;794 p->time_in_queue -= shared->tmp.time_in_queue;795 local_irq_enable();796 if (s->n_histogram_entries) {797 unsigned int i;798 799 for (i = 0; i < s->n_histogram_entries + 1; i++) {800 local_irq_disable();801 p = &s->stat_percpu[smp_processor_id()][x];802 p->histogram[i] -= shared->tmp.histogram[i];803 local_irq_enable();804 }805 }806 cond_resched();807 }808}809 810static int dm_stats_clear(struct dm_stats *stats, int id)811{812 struct dm_stat *s;813 814 mutex_lock(&stats->mutex);815 816 s = __dm_stats_find(stats, id);817 if (!s) {818 mutex_unlock(&stats->mutex);819 return -ENOENT;820 }821 822 __dm_stat_clear(s, 0, s->n_entries, true);823 824 mutex_unlock(&stats->mutex);825 826 return 1;827}828 829/*830 * This is like jiffies_to_msec, but works for 64-bit values.831 */832static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)833{834 unsigned long long result;835 unsigned int mult;836 837 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)838 return j;839 840 result = 0;841 if (j)842 result = jiffies_to_msecs(j & 0x3fffff);843 if (j >= 1 << 22) {844 mult = jiffies_to_msecs(1 << 22);845 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);846 }847 if (j >= 1ULL << 44)848 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);849 850 return result;851}852 853static int dm_stats_print(struct dm_stats *stats, int id,854 size_t idx_start, size_t idx_len,855 bool clear, char *result, unsigned int maxlen)856{857 unsigned int sz = 0;858 struct dm_stat *s;859 size_t x;860 sector_t start, end, step;861 size_t idx_end;862 struct dm_stat_shared *shared;863 864 /*865 * Output format:866 * <start_sector>+<length> counters867 */868 869 mutex_lock(&stats->mutex);870 871 s = __dm_stats_find(stats, id);872 if (!s) {873 mutex_unlock(&stats->mutex);874 return -ENOENT;875 }876 877 idx_end = idx_start + idx_len;878 if (idx_end < idx_start ||879 idx_end > s->n_entries)880 idx_end = s->n_entries;881 882 if (idx_start > idx_end)883 idx_start = idx_end;884 885 step = s->step;886 start = s->start + (step * idx_start);887 888 for (x = idx_start; x < idx_end; x++, start = end) {889 shared = &s->stat_shared[x];890 end = start + step;891 if (unlikely(end > s->end))892 end = s->end;893 894 __dm_stat_init_temporary_percpu_totals(shared, s, x);895 896 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",897 (unsigned long long)start,898 (unsigned long long)step,899 shared->tmp.ios[READ],900 shared->tmp.merges[READ],901 shared->tmp.sectors[READ],902 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),903 shared->tmp.ios[WRITE],904 shared->tmp.merges[WRITE],905 shared->tmp.sectors[WRITE],906 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),907 dm_stat_in_flight(shared),908 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),909 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),910 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),911 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));912 if (s->n_histogram_entries) {913 unsigned int i;914 915 for (i = 0; i < s->n_histogram_entries + 1; i++)916 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);917 }918 DMEMIT("\n");919 920 if (unlikely(sz + 1 >= maxlen))921 goto buffer_overflow;922 923 cond_resched();924 }925 926 if (clear)927 __dm_stat_clear(s, idx_start, idx_end, false);928 929buffer_overflow:930 mutex_unlock(&stats->mutex);931 932 return 1;933}934 935static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)936{937 struct dm_stat *s;938 const char *new_aux_data;939 940 mutex_lock(&stats->mutex);941 942 s = __dm_stats_find(stats, id);943 if (!s) {944 mutex_unlock(&stats->mutex);945 return -ENOENT;946 }947 948 new_aux_data = kstrdup(aux_data, GFP_KERNEL);949 if (!new_aux_data) {950 mutex_unlock(&stats->mutex);951 return -ENOMEM;952 }953 954 kfree(s->aux_data);955 s->aux_data = new_aux_data;956 957 mutex_unlock(&stats->mutex);958 959 return 0;960}961 962static int parse_histogram(const char *h, unsigned int *n_histogram_entries,963 unsigned long long **histogram_boundaries)964{965 const char *q;966 unsigned int n;967 unsigned long long last;968 969 *n_histogram_entries = 1;970 for (q = h; *q; q++)971 if (*q == ',')972 (*n_histogram_entries)++;973 974 *histogram_boundaries = kmalloc_array(*n_histogram_entries,975 sizeof(unsigned long long),976 GFP_KERNEL);977 if (!*histogram_boundaries)978 return -ENOMEM;979 980 n = 0;981 last = 0;982 while (1) {983 unsigned long long hi;984 int s;985 char ch;986 987 s = sscanf(h, "%llu%c", &hi, &ch);988 if (!s || (s == 2 && ch != ','))989 return -EINVAL;990 if (hi <= last)991 return -EINVAL;992 last = hi;993 (*histogram_boundaries)[n] = hi;994 if (s == 1)995 return 0;996 h = strchr(h, ',') + 1;997 n++;998 }999}1000 1001static int message_stats_create(struct mapped_device *md,1002 unsigned int argc, char **argv,1003 char *result, unsigned int maxlen)1004{1005 int r;1006 int id;1007 char dummy;1008 unsigned long long start, end, len, step;1009 unsigned int divisor;1010 const char *program_id, *aux_data;1011 unsigned int stat_flags = 0;1012 unsigned int n_histogram_entries = 0;1013 unsigned long long *histogram_boundaries = NULL;1014 struct dm_arg_set as, as_backup;1015 const char *a;1016 unsigned int feature_args;1017 1018 /*1019 * Input format:1020 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]1021 */1022 1023 if (argc < 3)1024 goto ret_einval;1025 1026 as.argc = argc;1027 as.argv = argv;1028 dm_consume_args(&as, 1);1029 1030 a = dm_shift_arg(&as);1031 if (!strcmp(a, "-")) {1032 start = 0;1033 len = dm_get_size(md);1034 if (!len)1035 len = 1;1036 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||1037 start != (sector_t)start || len != (sector_t)len)1038 goto ret_einval;1039 1040 end = start + len;1041 if (start >= end)1042 goto ret_einval;1043 1044 a = dm_shift_arg(&as);1045 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {1046 if (!divisor)1047 return -EINVAL;1048 step = end - start;1049 if (do_div(step, divisor))1050 step++;1051 if (!step)1052 step = 1;1053 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||1054 step != (sector_t)step || !step)1055 goto ret_einval;1056 1057 as_backup = as;1058 a = dm_shift_arg(&as);1059 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {1060 while (feature_args--) {1061 a = dm_shift_arg(&as);1062 if (!a)1063 goto ret_einval;1064 if (!strcasecmp(a, "precise_timestamps"))1065 stat_flags |= STAT_PRECISE_TIMESTAMPS;1066 else if (!strncasecmp(a, "histogram:", 10)) {1067 if (n_histogram_entries)1068 goto ret_einval;1069 r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries);1070 if (r)1071 goto ret;1072 } else1073 goto ret_einval;1074 }1075 } else {1076 as = as_backup;1077 }1078 1079 program_id = "-";1080 aux_data = "-";1081 1082 a = dm_shift_arg(&as);1083 if (a)1084 program_id = a;1085 1086 a = dm_shift_arg(&as);1087 if (a)1088 aux_data = a;1089 1090 if (as.argc)1091 goto ret_einval;1092 1093 /*1094 * If a buffer overflow happens after we created the region,1095 * it's too late (the userspace would retry with a larger1096 * buffer, but the region id that caused the overflow is already1097 * leaked). So we must detect buffer overflow in advance.1098 */1099 snprintf(result, maxlen, "%d", INT_MAX);1100 if (dm_message_test_buffer_overflow(result, maxlen)) {1101 r = 1;1102 goto ret;1103 }1104 1105 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,1106 n_histogram_entries, histogram_boundaries, program_id, aux_data,1107 dm_internal_suspend_fast, dm_internal_resume_fast, md);1108 if (id < 0) {1109 r = id;1110 goto ret;1111 }1112 1113 snprintf(result, maxlen, "%d", id);1114 1115 r = 1;1116 goto ret;1117 1118ret_einval:1119 r = -EINVAL;1120ret:1121 kfree(histogram_boundaries);1122 return r;1123}1124 1125static int message_stats_delete(struct mapped_device *md,1126 unsigned int argc, char **argv)1127{1128 int id;1129 char dummy;1130 1131 if (argc != 2)1132 return -EINVAL;1133 1134 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)1135 return -EINVAL;1136 1137 return dm_stats_delete(dm_get_stats(md), id);1138}1139 1140static int message_stats_clear(struct mapped_device *md,1141 unsigned int argc, char **argv)1142{1143 int id;1144 char dummy;1145 1146 if (argc != 2)1147 return -EINVAL;1148 1149 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)1150 return -EINVAL;1151 1152 return dm_stats_clear(dm_get_stats(md), id);1153}1154 1155static int message_stats_list(struct mapped_device *md,1156 unsigned int argc, char **argv,1157 char *result, unsigned int maxlen)1158{1159 int r;1160 const char *program = NULL;1161 1162 if (argc < 1 || argc > 2)1163 return -EINVAL;1164 1165 if (argc > 1) {1166 program = kstrdup(argv[1], GFP_KERNEL);1167 if (!program)1168 return -ENOMEM;1169 }1170 1171 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);1172 1173 kfree(program);1174 1175 return r;1176}1177 1178static int message_stats_print(struct mapped_device *md,1179 unsigned int argc, char **argv, bool clear,1180 char *result, unsigned int maxlen)1181{1182 int id;1183 char dummy;1184 unsigned long idx_start = 0, idx_len = ULONG_MAX;1185 1186 if (argc != 2 && argc != 4)1187 return -EINVAL;1188 1189 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)1190 return -EINVAL;1191 1192 if (argc > 3) {1193 if (strcmp(argv[2], "-") &&1194 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)1195 return -EINVAL;1196 if (strcmp(argv[3], "-") &&1197 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)1198 return -EINVAL;1199 }1200 1201 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,1202 result, maxlen);1203}1204 1205static int message_stats_set_aux(struct mapped_device *md,1206 unsigned int argc, char **argv)1207{1208 int id;1209 char dummy;1210 1211 if (argc != 3)1212 return -EINVAL;1213 1214 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)1215 return -EINVAL;1216 1217 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);1218}1219 1220int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,1221 char *result, unsigned int maxlen)1222{1223 int r;1224 1225 /* All messages here must start with '@' */1226 if (!strcasecmp(argv[0], "@stats_create"))1227 r = message_stats_create(md, argc, argv, result, maxlen);1228 else if (!strcasecmp(argv[0], "@stats_delete"))1229 r = message_stats_delete(md, argc, argv);1230 else if (!strcasecmp(argv[0], "@stats_clear"))1231 r = message_stats_clear(md, argc, argv);1232 else if (!strcasecmp(argv[0], "@stats_list"))1233 r = message_stats_list(md, argc, argv, result, maxlen);1234 else if (!strcasecmp(argv[0], "@stats_print"))1235 r = message_stats_print(md, argc, argv, false, result, maxlen);1236 else if (!strcasecmp(argv[0], "@stats_print_clear"))1237 r = message_stats_print(md, argc, argv, true, result, maxlen);1238 else if (!strcasecmp(argv[0], "@stats_set_aux"))1239 r = message_stats_set_aux(md, argc, argv);1240 else1241 return 2; /* this wasn't a stats message */1242 1243 if (r == -EINVAL)1244 DMCRIT("Invalid parameters for message %s", argv[0]);1245 1246 return r;1247}1248 1249int __init dm_statistics_init(void)1250{1251 shared_memory_amount = 0;1252 dm_stat_need_rcu_barrier = 0;1253 return 0;1254}1255 1256void dm_statistics_exit(void)1257{1258 if (dm_stat_need_rcu_barrier)1259 rcu_barrier();1260 if (WARN_ON(shared_memory_amount))1261 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);1262}1263 1264module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, 0444);1265MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");1266