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License cleanup: add SPDX GPL-2.0 license identifier to files with no license
[linux-block.git] / drivers / md / dm-stats.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
fd2ed4d2
MP		 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
4cc96131 14#include "dm-core.h"
fd2ed4d2
MP		 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 a
23 * 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;
dfcfac3e 33 unsigned long long *histogram;
fd2ed4d2
MP		 34};
35
36struct dm_stat_shared {
37 atomic_t in_flight[2];
c96aec34 38 unsigned long long stamp;
fd2ed4d2
MP		 39 struct dm_stat_percpu tmp;
40};
41
42struct dm_stat {
43 struct list_head list_entry;
44 int id;
c96aec34 45 unsigned stat_flags;
fd2ed4d2
MP		 46 size_t n_entries;
47 sector_t start;
48 sector_t end;
49 sector_t step;
dfcfac3e
MP		 50 unsigned n_histogram_entries;
51 unsigned long long *histogram_boundaries;
fd2ed4d2
MP		 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;
dfcfac3e 57 size_t histogram_alloc_size;
fd2ed4d2
MP		 58 struct dm_stat_percpu *stat_percpu[NR_CPUS];
59 struct dm_stat_shared stat_shared[0];
60};
61
c96aec34
MP		 62#define STAT_PRECISE_TIMESTAMPS 1
63
fd2ed4d2
MP		 64struct 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
77static DEFINE_SPINLOCK(shared_memory_lock);
78
79static unsigned long shared_memory_amount;
80
81static 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
97static 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
110static 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
126static 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
143static 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
a7c3e901 150 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
fd2ed4d2
MP		 151 if (p)
152 return p;
153
154 free_shared_memory(alloc_size);
155
156 return NULL;
157}
158
159static void dm_kvfree(void *ptr, size_t alloc_size)
160{
161 if (!ptr)
162 return;
163
164 free_shared_memory(alloc_size);
165
0f24b79b 166 kvfree(ptr);
fd2ed4d2
MP		 167}
168
169static 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
60858318 174 kfree(s->histogram_boundaries);
fd2ed4d2
MP		 175 kfree(s->program_id);
176 kfree(s->aux_data);
dfcfac3e
MP		 177 for_each_possible_cpu(cpu) {
178 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
fd2ed4d2 179 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
dfcfac3e
MP		 180 }
181 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
fd2ed4d2
MP		 182 dm_kvfree(s, s->shared_alloc_size);
183}
184
185static 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
191void 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->last = alloc_percpu(struct dm_stats_last_position);
199 for_each_possible_cpu(cpu) {
200 last = per_cpu_ptr(stats->last, cpu);
201 last->last_sector = (sector_t)ULLONG_MAX;
202 last->last_rw = UINT_MAX;
203 }
204}
205
206void dm_stats_cleanup(struct dm_stats *stats)
207{
208 size_t ni;
209 struct dm_stat *s;
210 struct dm_stat_shared *shared;
211
212 while (!list_empty(&stats->list)) {
213 s = container_of(stats->list.next, struct dm_stat, list_entry);
214 list_del(&s->list_entry);
215 for (ni = 0; ni < s->n_entries; ni++) {
216 shared = &s->stat_shared[ni];
217 if (WARN_ON(dm_stat_in_flight(shared))) {
218 DMCRIT("leaked in-flight counter at index %lu "
219 "(start %llu, end %llu, step %llu): reads %d, writes %d",
220 (unsigned long)ni,
221 (unsigned long long)s->start,
222 (unsigned long long)s->end,
223 (unsigned long long)s->step,
224 atomic_read(&shared->in_flight[READ]),
225 atomic_read(&shared->in_flight[WRITE]));
226 }
227 }
228 dm_stat_free(&s->rcu_head);
229 }
230 free_percpu(stats->last);
231}
232
233static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
c96aec34 234 sector_t step, unsigned stat_flags,
dfcfac3e
MP		 235 unsigned n_histogram_entries,
236 unsigned long long *histogram_boundaries,
c96aec34 237 const char *program_id, const char *aux_data,
fd2ed4d2
MP		 238 void (*suspend_callback)(struct mapped_device *),
239 void (*resume_callback)(struct mapped_device *),
240 struct mapped_device *md)
241{
242 struct list_head *l;
243 struct dm_stat *s, *tmp_s;
244 sector_t n_entries;
245 size_t ni;
246 size_t shared_alloc_size;
247 size_t percpu_alloc_size;
dfcfac3e 248 size_t histogram_alloc_size;
fd2ed4d2
MP		 249 struct dm_stat_percpu *p;
250 int cpu;
251 int ret_id;
252 int r;
253
254 if (end < start || !step)
255 return -EINVAL;
256
257 n_entries = end - start;
258 if (dm_sector_div64(n_entries, step))
259 n_entries++;
260
261 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
262 return -EOVERFLOW;
263
264 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
265 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
266 return -EOVERFLOW;
267
268 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
269 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
270 return -EOVERFLOW;
271
dfcfac3e
MP		 272 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
273 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
274 return -EOVERFLOW;
275
276 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
277 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
fd2ed4d2
MP		 278 return -ENOMEM;
279
280 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
281 if (!s)
282 return -ENOMEM;
283
c96aec34 284 s->stat_flags = stat_flags;
fd2ed4d2
MP		 285 s->n_entries = n_entries;
286 s->start = start;
287 s->end = end;
288 s->step = step;
289 s->shared_alloc_size = shared_alloc_size;
290 s->percpu_alloc_size = percpu_alloc_size;
dfcfac3e
MP		 291 s->histogram_alloc_size = histogram_alloc_size;
292
293 s->n_histogram_entries = n_histogram_entries;
294 s->histogram_boundaries = kmemdup(histogram_boundaries,
295 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
296 if (!s->histogram_boundaries) {
297 r = -ENOMEM;
298 goto out;
299 }
fd2ed4d2
MP		 300
301 s->program_id = kstrdup(program_id, GFP_KERNEL);
302 if (!s->program_id) {
303 r = -ENOMEM;
304 goto out;
305 }
306 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
307 if (!s->aux_data) {
308 r = -ENOMEM;
309 goto out;
310 }
311
312 for (ni = 0; ni < n_entries; ni++) {
313 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
314 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
315 }
316
dfcfac3e
MP		 317 if (s->n_histogram_entries) {
318 unsigned long long *hi;
319 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
320 if (!hi) {
321 r = -ENOMEM;
322 goto out;
323 }
324 for (ni = 0; ni < n_entries; ni++) {
325 s->stat_shared[ni].tmp.histogram = hi;
326 hi += s->n_histogram_entries + 1;
327 }
328 }
329
fd2ed4d2
MP		 330 for_each_possible_cpu(cpu) {
331 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
332 if (!p) {
333 r = -ENOMEM;
334 goto out;
335 }
336 s->stat_percpu[cpu] = p;
dfcfac3e
MP		 337 if (s->n_histogram_entries) {
338 unsigned long long *hi;
339 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
340 if (!hi) {
341 r = -ENOMEM;
342 goto out;
343 }
344 for (ni = 0; ni < n_entries; ni++) {
345 p[ni].histogram = hi;
346 hi += s->n_histogram_entries + 1;
347 }
348 }
fd2ed4d2
MP		 349 }
350
351 /*
352 * Suspend/resume to make sure there is no i/o in flight,
353 * so that newly created statistics will be exact.
354 *
355 * (note: we couldn't suspend earlier because we must not
356 * allocate memory while suspended)
357 */
358 suspend_callback(md);
359
360 mutex_lock(&stats->mutex);
361 s->id = 0;
362 list_for_each(l, &stats->list) {
363 tmp_s = container_of(l, struct dm_stat, list_entry);
364 if (WARN_ON(tmp_s->id < s->id)) {
365 r = -EINVAL;
366 goto out_unlock_resume;
367 }
368 if (tmp_s->id > s->id)
369 break;
370 if (unlikely(s->id == INT_MAX)) {
371 r = -ENFILE;
372 goto out_unlock_resume;
373 }
374 s->id++;
375 }
376 ret_id = s->id;
377 list_add_tail_rcu(&s->list_entry, l);
378 mutex_unlock(&stats->mutex);
379
380 resume_callback(md);
381
382 return ret_id;
383
384out_unlock_resume:
385 mutex_unlock(&stats->mutex);
386 resume_callback(md);
387out:
388 dm_stat_free(&s->rcu_head);
389 return r;
390}
391
392static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
393{
394 struct dm_stat *s;
395
396 list_for_each_entry(s, &stats->list, list_entry) {
397 if (s->id > id)
398 break;
399 if (s->id == id)
400 return s;
401 }
402
403 return NULL;
404}
405
406static int dm_stats_delete(struct dm_stats *stats, int id)
407{
408 struct dm_stat *s;
409 int cpu;
410
411 mutex_lock(&stats->mutex);
412
413 s = __dm_stats_find(stats, id);
414 if (!s) {
415 mutex_unlock(&stats->mutex);
416 return -ENOENT;
417 }
418
419 list_del_rcu(&s->list_entry);
420 mutex_unlock(&stats->mutex);
421
422 /*
423 * vfree can't be called from RCU callback
424 */
425 for_each_possible_cpu(cpu)
dfcfac3e
MP		 426 if (is_vmalloc_addr(s->stat_percpu) ||
427 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
fd2ed4d2 428 goto do_sync_free;
dfcfac3e
MP		 429 if (is_vmalloc_addr(s) ||
430 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
fd2ed4d2
MP		 431do_sync_free:
432 synchronize_rcu_expedited();
433 dm_stat_free(&s->rcu_head);
434 } else {
435 ACCESS_ONCE(dm_stat_need_rcu_barrier) = 1;
436 call_rcu(&s->rcu_head, dm_stat_free);
437 }
438 return 0;
439}
440
441static int dm_stats_list(struct dm_stats *stats, const char *program,
442 char *result, unsigned maxlen)
443{
444 struct dm_stat *s;
445 sector_t len;
446 unsigned sz = 0;
447
448 /*
449 * Output format:
450 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
451 */
452
453 mutex_lock(&stats->mutex);
454 list_for_each_entry(s, &stats->list, list_entry) {
455 if (!program || !strcmp(program, s->program_id)) {
456 len = s->end - s->start;
bd49784f 457 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
fd2ed4d2
MP		 458 (unsigned long long)s->start,
459 (unsigned long long)len,
460 (unsigned long long)s->step,
461 s->program_id,
462 s->aux_data);
bd49784f
MP		 463 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
464 DMEMIT(" precise_timestamps");
465 if (s->n_histogram_entries) {
466 unsigned i;
467 DMEMIT(" histogram:");
468 for (i = 0; i < s->n_histogram_entries; i++) {
469 if (i)
470 DMEMIT(",");
471 DMEMIT("%llu", s->histogram_boundaries[i]);
472 }
473 }
474 DMEMIT("\n");
fd2ed4d2
MP		 475 }
476 }
477 mutex_unlock(&stats->mutex);
478
479 return 1;
480}
481
c96aec34
MP		 482static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
483 struct dm_stat_percpu *p)
fd2ed4d2
MP		 484{
485 /*
486 * This is racy, but so is part_round_stats_single.
487 */
c96aec34
MP		 488 unsigned long long now, difference;
489 unsigned in_flight_read, in_flight_write;
490
491 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
492 now = jiffies;
493 else
494 now = ktime_to_ns(ktime_get());
fd2ed4d2 495
c96aec34 496 difference = now - shared->stamp;
fd2ed4d2
MP		 497 if (!difference)
498 return;
c96aec34 499
fd2ed4d2
MP		 500 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
501 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
502 if (in_flight_read)
503 p->io_ticks[READ] += difference;
504 if (in_flight_write)
505 p->io_ticks[WRITE] += difference;
506 if (in_flight_read + in_flight_write) {
507 p->io_ticks_total += difference;
508 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
509 }
510 shared->stamp = now;
511}
512
513static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
528ec5ab 514 int idx, sector_t len,
c96aec34
MP		 515 struct dm_stats_aux *stats_aux, bool end,
516 unsigned long duration_jiffies)
fd2ed4d2 517{
fd2ed4d2
MP		 518 struct dm_stat_shared *shared = &s->stat_shared[entry];
519 struct dm_stat_percpu *p;
520
521 /*
bbf3f8cb 522 * For strict correctness we should use local_irq_save/restore
fd2ed4d2
MP		 523 * instead of preempt_disable/enable.
524 *
bbf3f8cb
MP		 525 * preempt_disable/enable is racy if the driver finishes bios
526 * from non-interrupt context as well as from interrupt context
527 * or from more different interrupts.
fd2ed4d2 528 *
bbf3f8cb
MP		 529 * On 64-bit architectures the race only results in not counting some
530 * events, so it is acceptable. On 32-bit architectures the race could
531 * cause the counter going off by 2^32, so we need to do proper locking
532 * there.
fd2ed4d2
MP		 533 *
534 * part_stat_lock()/part_stat_unlock() have this race too.
535 */
bbf3f8cb
MP		 536#if BITS_PER_LONG == 32
537 unsigned long flags;
538 local_irq_save(flags);
539#else
fd2ed4d2 540 preempt_disable();
bbf3f8cb 541#endif
fd2ed4d2
MP		 542 p = &s->stat_percpu[smp_processor_id()][entry];
543
544 if (!end) {
c96aec34 545 dm_stat_round(s, shared, p);
fd2ed4d2
MP		 546 atomic_inc(&shared->in_flight[idx]);
547 } else {
dfcfac3e 548 unsigned long long duration;
c96aec34 549 dm_stat_round(s, shared, p);
fd2ed4d2
MP		 550 atomic_dec(&shared->in_flight[idx]);
551 p->sectors[idx] += len;
552 p->ios[idx] += 1;
c96aec34 553 p->merges[idx] += stats_aux->merged;
dfcfac3e 554 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
c96aec34 555 p->ticks[idx] += duration_jiffies;
dfcfac3e
MP		 556 duration = jiffies_to_msecs(duration_jiffies);
557 } else {
c96aec34 558 p->ticks[idx] += stats_aux->duration_ns;
dfcfac3e
MP		 559 duration = stats_aux->duration_ns;
560 }
561 if (s->n_histogram_entries) {
562 unsigned lo = 0, hi = s->n_histogram_entries + 1;
563 while (lo + 1 < hi) {
564 unsigned mid = (lo + hi) / 2;
565 if (s->histogram_boundaries[mid - 1] > duration) {
566 hi = mid;
567 } else {
568 lo = mid;
569 }
570
571 }
572 p->histogram[lo]++;
573 }
fd2ed4d2
MP		 574 }
575
bbf3f8cb
MP		 576#if BITS_PER_LONG == 32
577 local_irq_restore(flags);
578#else
fd2ed4d2 579 preempt_enable();
bbf3f8cb 580#endif
fd2ed4d2
MP		 581}
582
528ec5ab 583static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
fd2ed4d2 584 sector_t bi_sector, sector_t end_sector,
c96aec34 585 bool end, unsigned long duration_jiffies,
fd2ed4d2
MP		 586 struct dm_stats_aux *stats_aux)
587{
588 sector_t rel_sector, offset, todo, fragment_len;
589 size_t entry;
590
591 if (end_sector <= s->start || bi_sector >= s->end)
592 return;
593 if (unlikely(bi_sector < s->start)) {
594 rel_sector = 0;
595 todo = end_sector - s->start;
596 } else {
597 rel_sector = bi_sector - s->start;
598 todo = end_sector - bi_sector;
599 }
600 if (unlikely(end_sector > s->end))
601 todo -= (end_sector - s->end);
602
603 offset = dm_sector_div64(rel_sector, s->step);
604 entry = rel_sector;
605 do {
606 if (WARN_ON_ONCE(entry >= s->n_entries)) {
607 DMCRIT("Invalid area access in region id %d", s->id);
608 return;
609 }
610 fragment_len = todo;
611 if (fragment_len > s->step - offset)
612 fragment_len = s->step - offset;
613 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
c96aec34 614 stats_aux, end, duration_jiffies);
fd2ed4d2
MP		 615 todo -= fragment_len;
616 entry++;
617 offset = 0;
618 } while (unlikely(todo != 0));
619}
620
621void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
622 sector_t bi_sector, unsigned bi_sectors, bool end,
c96aec34
MP		 623 unsigned long duration_jiffies,
624 struct dm_stats_aux *stats_aux)
fd2ed4d2
MP		 625{
626 struct dm_stat *s;
627 sector_t end_sector;
628 struct dm_stats_last_position *last;
c96aec34 629 bool got_precise_time;
fd2ed4d2
MP		 630
631 if (unlikely(!bi_sectors))
632 return;
633
634 end_sector = bi_sector + bi_sectors;
635
636 if (!end) {
637 /*
638 * A race condition can at worst result in the merged flag being
639 * misrepresented, so we don't have to disable preemption here.
640 */
1f125e76 641 last = raw_cpu_ptr(stats->last);
fd2ed4d2
MP		 642 stats_aux->merged =
643 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
528ec5ab
MC		 644 ((bi_rw == WRITE) ==
645 (ACCESS_ONCE(last->last_rw) == WRITE))
fd2ed4d2
MP		 646 ));
647 ACCESS_ONCE(last->last_sector) = end_sector;
648 ACCESS_ONCE(last->last_rw) = bi_rw;
649 }
650
651 rcu_read_lock();
652
c96aec34
MP		 653 got_precise_time = false;
654 list_for_each_entry_rcu(s, &stats->list, list_entry) {
655 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
656 if (!end)
657 stats_aux->duration_ns = ktime_to_ns(ktime_get());
658 else
659 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
660 got_precise_time = true;
661 }
662 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
663 }
fd2ed4d2
MP		 664
665 rcu_read_unlock();
666}
667
668static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
669 struct dm_stat *s, size_t x)
670{
671 int cpu;
672 struct dm_stat_percpu *p;
673
674 local_irq_disable();
675 p = &s->stat_percpu[smp_processor_id()][x];
c96aec34 676 dm_stat_round(s, shared, p);
fd2ed4d2
MP		 677 local_irq_enable();
678
dfcfac3e
MP		 679 shared->tmp.sectors[READ] = 0;
680 shared->tmp.sectors[WRITE] = 0;
681 shared->tmp.ios[READ] = 0;
682 shared->tmp.ios[WRITE] = 0;
683 shared->tmp.merges[READ] = 0;
684 shared->tmp.merges[WRITE] = 0;
685 shared->tmp.ticks[READ] = 0;
686 shared->tmp.ticks[WRITE] = 0;
687 shared->tmp.io_ticks[READ] = 0;
688 shared->tmp.io_ticks[WRITE] = 0;
689 shared->tmp.io_ticks_total = 0;
690 shared->tmp.time_in_queue = 0;
691
692 if (s->n_histogram_entries)
693 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
694
fd2ed4d2
MP		 695 for_each_possible_cpu(cpu) {
696 p = &s->stat_percpu[cpu][x];
697 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
698 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
699 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
700 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
701 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
702 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
703 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
704 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
705 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
706 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
707 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
708 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
dfcfac3e
MP		 709 if (s->n_histogram_entries) {
710 unsigned i;
711 for (i = 0; i < s->n_histogram_entries + 1; i++)
712 shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]);
713 }
fd2ed4d2
MP		 714 }
715}
716
717static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
718 bool init_tmp_percpu_totals)
719{
720 size_t x;
721 struct dm_stat_shared *shared;
722 struct dm_stat_percpu *p;
723
724 for (x = idx_start; x < idx_end; x++) {
725 shared = &s->stat_shared[x];
726 if (init_tmp_percpu_totals)
727 __dm_stat_init_temporary_percpu_totals(shared, s, x);
728 local_irq_disable();
729 p = &s->stat_percpu[smp_processor_id()][x];
730 p->sectors[READ] -= shared->tmp.sectors[READ];
731 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
732 p->ios[READ] -= shared->tmp.ios[READ];
733 p->ios[WRITE] -= shared->tmp.ios[WRITE];
734 p->merges[READ] -= shared->tmp.merges[READ];
735 p->merges[WRITE] -= shared->tmp.merges[WRITE];
736 p->ticks[READ] -= shared->tmp.ticks[READ];
737 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
738 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
739 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
740 p->io_ticks_total -= shared->tmp.io_ticks_total;
741 p->time_in_queue -= shared->tmp.time_in_queue;
742 local_irq_enable();
dfcfac3e
MP		 743 if (s->n_histogram_entries) {
744 unsigned i;
745 for (i = 0; i < s->n_histogram_entries + 1; i++) {
746 local_irq_disable();
747 p = &s->stat_percpu[smp_processor_id()][x];
748 p->histogram[i] -= shared->tmp.histogram[i];
749 local_irq_enable();
750 }
751 }
fd2ed4d2
MP		 752 }
753}
754
755static int dm_stats_clear(struct dm_stats *stats, int id)
756{
757 struct dm_stat *s;
758
759 mutex_lock(&stats->mutex);
760
761 s = __dm_stats_find(stats, id);
762 if (!s) {
763 mutex_unlock(&stats->mutex);
764 return -ENOENT;
765 }
766
767 __dm_stat_clear(s, 0, s->n_entries, true);
768
769 mutex_unlock(&stats->mutex);
770
771 return 1;
772}
773
774/*
775 * This is like jiffies_to_msec, but works for 64-bit values.
776 */
c96aec34 777static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
fd2ed4d2 778{
c96aec34 779 unsigned long long result;
fd2ed4d2
MP		 780 unsigned mult;
781
c96aec34
MP		 782 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
783 return j;
784
785 result = 0;
fd2ed4d2
MP		 786 if (j)
787 result = jiffies_to_msecs(j & 0x3fffff);
788 if (j >= 1 << 22) {
789 mult = jiffies_to_msecs(1 << 22);
790 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
791 }
792 if (j >= 1ULL << 44)
793 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
794
795 return result;
796}
797
798static int dm_stats_print(struct dm_stats *stats, int id,
799 size_t idx_start, size_t idx_len,
800 bool clear, char *result, unsigned maxlen)
801{
802 unsigned sz = 0;
803 struct dm_stat *s;
804 size_t x;
805 sector_t start, end, step;
806 size_t idx_end;
807 struct dm_stat_shared *shared;
808
809 /*
810 * Output format:
811 * <start_sector>+<length> counters
812 */
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 idx_end = idx_start + idx_len;
823 if (idx_end < idx_start ||
824 idx_end > s->n_entries)
825 idx_end = s->n_entries;
826
827 if (idx_start > idx_end)
828 idx_start = idx_end;
829
830 step = s->step;
831 start = s->start + (step * idx_start);
832
833 for (x = idx_start; x < idx_end; x++, start = end) {
834 shared = &s->stat_shared[x];
835 end = start + step;
836 if (unlikely(end > s->end))
837 end = s->end;
838
839 __dm_stat_init_temporary_percpu_totals(shared, s, x);
840
dfcfac3e 841 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
fd2ed4d2
MP		 842 (unsigned long long)start,
843 (unsigned long long)step,
844 shared->tmp.ios[READ],
845 shared->tmp.merges[READ],
846 shared->tmp.sectors[READ],
c96aec34 847 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
fd2ed4d2
MP		 848 shared->tmp.ios[WRITE],
849 shared->tmp.merges[WRITE],
850 shared->tmp.sectors[WRITE],
c96aec34 851 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
fd2ed4d2 852 dm_stat_in_flight(shared),
c96aec34
MP		 853 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
854 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
855 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
856 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
dfcfac3e
MP		 857 if (s->n_histogram_entries) {
858 unsigned i;
859 for (i = 0; i < s->n_histogram_entries + 1; i++) {
860 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
861 }
862 }
863 DMEMIT("\n");
fd2ed4d2
MP		 864
865 if (unlikely(sz + 1 >= maxlen))
866 goto buffer_overflow;
867 }
868
869 if (clear)
870 __dm_stat_clear(s, idx_start, idx_end, false);
871
872buffer_overflow:
873 mutex_unlock(&stats->mutex);
874
875 return 1;
876}
877
878static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
879{
880 struct dm_stat *s;
881 const char *new_aux_data;
882
883 mutex_lock(&stats->mutex);
884
885 s = __dm_stats_find(stats, id);
886 if (!s) {
887 mutex_unlock(&stats->mutex);
888 return -ENOENT;
889 }
890
891 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
892 if (!new_aux_data) {
893 mutex_unlock(&stats->mutex);
894 return -ENOMEM;
895 }
896
897 kfree(s->aux_data);
898 s->aux_data = new_aux_data;
899
900 mutex_unlock(&stats->mutex);
901
902 return 0;
903}
904
dfcfac3e
MP		 905static int parse_histogram(const char *h, unsigned *n_histogram_entries,
906 unsigned long long **histogram_boundaries)
907{
908 const char *q;
909 unsigned n;
910 unsigned long long last;
911
912 *n_histogram_entries = 1;
913 for (q = h; *q; q++)
914 if (*q == ',')
915 (*n_histogram_entries)++;
916
917 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
918 if (!*histogram_boundaries)
919 return -ENOMEM;
920
921 n = 0;
922 last = 0;
923 while (1) {
924 unsigned long long hi;
925 int s;
926 char ch;
927 s = sscanf(h, "%llu%c", &hi, &ch);
928 if (!s || (s == 2 && ch != ','))
929 return -EINVAL;
930 if (hi <= last)
931 return -EINVAL;
932 last = hi;
933 (*histogram_boundaries)[n] = hi;
934 if (s == 1)
935 return 0;
936 h = strchr(h, ',') + 1;
937 n++;
938 }
939}
940
fd2ed4d2
MP		 941static int message_stats_create(struct mapped_device *md,
942 unsigned argc, char **argv,
943 char *result, unsigned maxlen)
944{
dfcfac3e 945 int r;
fd2ed4d2
MP		 946 int id;
947 char dummy;
948 unsigned long long start, end, len, step;
949 unsigned divisor;
950 const char *program_id, *aux_data;
c96aec34
MP		 951 unsigned stat_flags = 0;
952
dfcfac3e
MP		 953 unsigned n_histogram_entries = 0;
954 unsigned long long *histogram_boundaries = NULL;
955
c96aec34
MP		 956 struct dm_arg_set as, as_backup;
957 const char *a;
958 unsigned feature_args;
fd2ed4d2
MP		 959
960 /*
961 * Input format:
c96aec34 962 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
fd2ed4d2
MP		 963 */
964
c96aec34 965 if (argc < 3)
dfcfac3e 966 goto ret_einval;
fd2ed4d2 967
c96aec34
MP		 968 as.argc = argc;
969 as.argv = argv;
970 dm_consume_args(&as, 1);
971
972 a = dm_shift_arg(&as);
973 if (!strcmp(a, "-")) {
fd2ed4d2
MP		 974 start = 0;
975 len = dm_get_size(md);
976 if (!len)
977 len = 1;
c96aec34 978 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
fd2ed4d2 979 start != (sector_t)start || len != (sector_t)len)
dfcfac3e 980 goto ret_einval;
fd2ed4d2
MP		 981
982 end = start + len;
983 if (start >= end)
dfcfac3e 984 goto ret_einval;
fd2ed4d2 985
c96aec34
MP		 986 a = dm_shift_arg(&as);
987 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
dd4c1b7d
MP		 988 if (!divisor)
989 return -EINVAL;
fd2ed4d2
MP		 990 step = end - start;
991 if (do_div(step, divisor))
992 step++;
993 if (!step)
994 step = 1;
c96aec34 995 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
fd2ed4d2 996 step != (sector_t)step || !step)
dfcfac3e 997 goto ret_einval;
fd2ed4d2 998
c96aec34
MP		 999 as_backup = as;
1000 a = dm_shift_arg(&as);
1001 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1002 while (feature_args--) {
1003 a = dm_shift_arg(&as);
1004 if (!a)
dfcfac3e 1005 goto ret_einval;
c96aec34
MP		 1006 if (!strcasecmp(a, "precise_timestamps"))
1007 stat_flags |= STAT_PRECISE_TIMESTAMPS;
dfcfac3e
MP		 1008 else if (!strncasecmp(a, "histogram:", 10)) {
1009 if (n_histogram_entries)
1010 goto ret_einval;
1011 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1012 goto ret;
1013 } else
1014 goto ret_einval;
c96aec34
MP		 1015 }
1016 } else {
1017 as = as_backup;
1018 }
1019
fd2ed4d2
MP		 1020 program_id = "-";
1021 aux_data = "-";
1022
c96aec34
MP		 1023 a = dm_shift_arg(&as);
1024 if (a)
1025 program_id = a;
1026
1027 a = dm_shift_arg(&as);
1028 if (a)
1029 aux_data = a;
fd2ed4d2 1030
c96aec34 1031 if (as.argc)
dfcfac3e 1032 goto ret_einval;
fd2ed4d2
MP		 1033
1034 /*
1035 * If a buffer overflow happens after we created the region,
1036 * it's too late (the userspace would retry with a larger
1037 * buffer, but the region id that caused the overflow is already
1038 * leaked). So we must detect buffer overflow in advance.
1039 */
1040 snprintf(result, maxlen, "%d", INT_MAX);
dfcfac3e
MP		 1041 if (dm_message_test_buffer_overflow(result, maxlen)) {
1042 r = 1;
1043 goto ret;
1044 }
fd2ed4d2 1045
dfcfac3e
MP		 1046 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1047 n_histogram_entries, histogram_boundaries, program_id, aux_data,
ffcc3936 1048 dm_internal_suspend_fast, dm_internal_resume_fast, md);
dfcfac3e
MP		 1049 if (id < 0) {
1050 r = id;
1051 goto ret;
1052 }
fd2ed4d2
MP		 1053
1054 snprintf(result, maxlen, "%d", id);
1055
dfcfac3e
MP		 1056 r = 1;
1057 goto ret;
1058
1059ret_einval:
1060 r = -EINVAL;
1061ret:
1062 kfree(histogram_boundaries);
1063 return r;
fd2ed4d2
MP		 1064}
1065
1066static int message_stats_delete(struct mapped_device *md,
1067 unsigned argc, char **argv)
1068{
1069 int id;
1070 char dummy;
1071
1072 if (argc != 2)
1073 return -EINVAL;
1074
1075 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1076 return -EINVAL;
1077
1078 return dm_stats_delete(dm_get_stats(md), id);
1079}
1080
1081static int message_stats_clear(struct mapped_device *md,
1082 unsigned argc, char **argv)
1083{
1084 int id;
1085 char dummy;
1086
1087 if (argc != 2)
1088 return -EINVAL;
1089
1090 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1091 return -EINVAL;
1092
1093 return dm_stats_clear(dm_get_stats(md), id);
1094}
1095
1096static int message_stats_list(struct mapped_device *md,
1097 unsigned argc, char **argv,
1098 char *result, unsigned maxlen)
1099{
1100 int r;
1101 const char *program = NULL;
1102
1103 if (argc < 1 || argc > 2)
1104 return -EINVAL;
1105
1106 if (argc > 1) {
1107 program = kstrdup(argv[1], GFP_KERNEL);
1108 if (!program)
1109 return -ENOMEM;
1110 }
1111
1112 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1113
1114 kfree(program);
1115
1116 return r;
1117}
1118
1119static int message_stats_print(struct mapped_device *md,
1120 unsigned argc, char **argv, bool clear,
1121 char *result, unsigned maxlen)
1122{
1123 int id;
1124 char dummy;
1125 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1126
1127 if (argc != 2 && argc != 4)
1128 return -EINVAL;
1129
1130 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1131 return -EINVAL;
1132
1133 if (argc > 3) {
1134 if (strcmp(argv[2], "-") &&
1135 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1136 return -EINVAL;
1137 if (strcmp(argv[3], "-") &&
1138 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1139 return -EINVAL;
1140 }
1141
1142 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1143 result, maxlen);
1144}
1145
1146static int message_stats_set_aux(struct mapped_device *md,
1147 unsigned argc, char **argv)
1148{
1149 int id;
1150 char dummy;
1151
1152 if (argc != 3)
1153 return -EINVAL;
1154
1155 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1156 return -EINVAL;
1157
1158 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1159}
1160
1161int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1162 char *result, unsigned maxlen)
1163{
1164 int r;
1165
fd2ed4d2
MP		 1166 /* All messages here must start with '@' */
1167 if (!strcasecmp(argv[0], "@stats_create"))
1168 r = message_stats_create(md, argc, argv, result, maxlen);
1169 else if (!strcasecmp(argv[0], "@stats_delete"))
1170 r = message_stats_delete(md, argc, argv);
1171 else if (!strcasecmp(argv[0], "@stats_clear"))
1172 r = message_stats_clear(md, argc, argv);
1173 else if (!strcasecmp(argv[0], "@stats_list"))
1174 r = message_stats_list(md, argc, argv, result, maxlen);
1175 else if (!strcasecmp(argv[0], "@stats_print"))
1176 r = message_stats_print(md, argc, argv, false, result, maxlen);
1177 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1178 r = message_stats_print(md, argc, argv, true, result, maxlen);
1179 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1180 r = message_stats_set_aux(md, argc, argv);
1181 else
1182 return 2; /* this wasn't a stats message */
1183
1184 if (r == -EINVAL)
1185 DMWARN("Invalid parameters for message %s", argv[0]);
1186
1187 return r;
1188}
1189
1190int __init dm_statistics_init(void)
1191{
76f5bee5 1192 shared_memory_amount = 0;
fd2ed4d2
MP		 1193 dm_stat_need_rcu_barrier = 0;
1194 return 0;
1195}
1196
1197void dm_statistics_exit(void)
1198{
1199 if (dm_stat_need_rcu_barrier)
1200 rcu_barrier();
1201 if (WARN_ON(shared_memory_amount))
1202 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1203}
1204
1205module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1206MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
Linux 6.x block layer and io_uring tree(s)