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Linux 4.19.133
[linux/fpc-iii.git] / drivers / md / dm-stats.c
blob21de30b4e2a16051490ce5a2548c3711a3f0284e
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[0];
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->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
206 void 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 mutex_destroy(&stats->mutex);
232 }
233
234 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
235 sector_t step, unsigned stat_flags,
236 unsigned n_histogram_entries,
237 unsigned long long *histogram_boundaries,
238 const char *program_id, const char *aux_data,
239 void (*suspend_callback)(struct mapped_device *),
240 void (*resume_callback)(struct mapped_device *),
241 struct mapped_device *md)
242 {
243 struct list_head *l;
244 struct dm_stat *s, *tmp_s;
245 sector_t n_entries;
246 size_t ni;
247 size_t shared_alloc_size;
248 size_t percpu_alloc_size;
249 size_t histogram_alloc_size;
250 struct dm_stat_percpu *p;
251 int cpu;
252 int ret_id;
253 int r;
254
255 if (end < start || !step)
256 return -EINVAL;
257
258 n_entries = end - start;
259 if (dm_sector_div64(n_entries, step))
260 n_entries++;
261
262 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
263 return -EOVERFLOW;
264
265 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
266 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
267 return -EOVERFLOW;
268
269 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
270 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
271 return -EOVERFLOW;
272
273 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
274 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
275 return -EOVERFLOW;
276
277 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
278 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
279 return -ENOMEM;
280
281 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
282 if (!s)
283 return -ENOMEM;
284
285 s->stat_flags = stat_flags;
286 s->n_entries = n_entries;
287 s->start = start;
288 s->end = end;
289 s->step = step;
290 s->shared_alloc_size = shared_alloc_size;
291 s->percpu_alloc_size = percpu_alloc_size;
292 s->histogram_alloc_size = histogram_alloc_size;
293
294 s->n_histogram_entries = n_histogram_entries;
295 s->histogram_boundaries = kmemdup(histogram_boundaries,
296 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
297 if (!s->histogram_boundaries) {
298 r = -ENOMEM;
299 goto out;
300 }
301
302 s->program_id = kstrdup(program_id, GFP_KERNEL);
303 if (!s->program_id) {
304 r = -ENOMEM;
305 goto out;
306 }
307 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
308 if (!s->aux_data) {
309 r = -ENOMEM;
310 goto out;
311 }
312
313 for (ni = 0; ni < n_entries; ni++) {
314 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
315 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
316 }
317
318 if (s->n_histogram_entries) {
319 unsigned long long *hi;
320 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
321 if (!hi) {
322 r = -ENOMEM;
323 goto out;
324 }
325 for (ni = 0; ni < n_entries; ni++) {
326 s->stat_shared[ni].tmp.histogram = hi;
327 hi += s->n_histogram_entries + 1;
328 }
329 }
330
331 for_each_possible_cpu(cpu) {
332 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
333 if (!p) {
334 r = -ENOMEM;
335 goto out;
336 }
337 s->stat_percpu[cpu] = p;
338 if (s->n_histogram_entries) {
339 unsigned long long *hi;
340 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
341 if (!hi) {
342 r = -ENOMEM;
343 goto out;
344 }
345 for (ni = 0; ni < n_entries; ni++) {
346 p[ni].histogram = hi;
347 hi += s->n_histogram_entries + 1;
348 }
349 }
350 }
351
352 /*
353 * Suspend/resume to make sure there is no i/o in flight,
354 * so that newly created statistics will be exact.
355 *
356 * (note: we couldn't suspend earlier because we must not
357 * allocate memory while suspended)
358 */
359 suspend_callback(md);
360
361 mutex_lock(&stats->mutex);
362 s->id = 0;
363 list_for_each(l, &stats->list) {
364 tmp_s = container_of(l, struct dm_stat, list_entry);
365 if (WARN_ON(tmp_s->id < s->id)) {
366 r = -EINVAL;
367 goto out_unlock_resume;
368 }
369 if (tmp_s->id > s->id)
370 break;
371 if (unlikely(s->id == INT_MAX)) {
372 r = -ENFILE;
373 goto out_unlock_resume;
374 }
375 s->id++;
376 }
377 ret_id = s->id;
378 list_add_tail_rcu(&s->list_entry, l);
379 mutex_unlock(&stats->mutex);
380
381 resume_callback(md);
382
383 return ret_id;
384
385 out_unlock_resume:
386 mutex_unlock(&stats->mutex);
387 resume_callback(md);
388 out:
389 dm_stat_free(&s->rcu_head);
390 return r;
391 }
392
393 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
394 {
395 struct dm_stat *s;
396
397 list_for_each_entry(s, &stats->list, list_entry) {
398 if (s->id > id)
399 break;
400 if (s->id == id)
401 return s;
402 }
403
404 return NULL;
405 }
406
407 static int dm_stats_delete(struct dm_stats *stats, int id)
408 {
409 struct dm_stat *s;
410 int cpu;
411
412 mutex_lock(&stats->mutex);
413
414 s = __dm_stats_find(stats, id);
415 if (!s) {
416 mutex_unlock(&stats->mutex);
417 return -ENOENT;
418 }
419
420 list_del_rcu(&s->list_entry);
421 mutex_unlock(&stats->mutex);
422
423 /*
424 * vfree can't be called from RCU callback
425 */
426 for_each_possible_cpu(cpu)
427 if (is_vmalloc_addr(s->stat_percpu) ||
428 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
429 goto do_sync_free;
430 if (is_vmalloc_addr(s) ||
431 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
432 do_sync_free:
433 synchronize_rcu_expedited();
434 dm_stat_free(&s->rcu_head);
435 } else {
436 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
437 call_rcu(&s->rcu_head, dm_stat_free);
438 }
439 return 0;
440 }
441
442 static int dm_stats_list(struct dm_stats *stats, const char *program,
443 char *result, unsigned maxlen)
444 {
445 struct dm_stat *s;
446 sector_t len;
447 unsigned sz = 0;
448
449 /*
450 * Output format:
451 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
452 */
453
454 mutex_lock(&stats->mutex);
455 list_for_each_entry(s, &stats->list, list_entry) {
456 if (!program || !strcmp(program, s->program_id)) {
457 len = s->end - s->start;
458 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
459 (unsigned long long)s->start,
460 (unsigned long long)len,
461 (unsigned long long)s->step,
462 s->program_id,
463 s->aux_data);
464 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
465 DMEMIT(" precise_timestamps");
466 if (s->n_histogram_entries) {
467 unsigned i;
468 DMEMIT(" histogram:");
469 for (i = 0; i < s->n_histogram_entries; i++) {
470 if (i)
471 DMEMIT(",");
472 DMEMIT("%llu", s->histogram_boundaries[i]);
473 }
474 }
475 DMEMIT("\n");
476 }
477 }
478 mutex_unlock(&stats->mutex);
479
480 return 1;
481 }
482
483 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
484 struct dm_stat_percpu *p)
485 {
486 /*
487 * This is racy, but so is part_round_stats_single.
488 */
489 unsigned long long now, difference;
490 unsigned in_flight_read, in_flight_write;
491
492 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
493 now = jiffies;
494 else
495 now = ktime_to_ns(ktime_get());
496
497 difference = now - shared->stamp;
498 if (!difference)
499 return;
500
501 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
502 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
503 if (in_flight_read)
504 p->io_ticks[READ] += difference;
505 if (in_flight_write)
506 p->io_ticks[WRITE] += difference;
507 if (in_flight_read + in_flight_write) {
508 p->io_ticks_total += difference;
509 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
510 }
511 shared->stamp = now;
512 }
513
514 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
515 int idx, sector_t len,
516 struct dm_stats_aux *stats_aux, bool end,
517 unsigned long duration_jiffies)
518 {
519 struct dm_stat_shared *shared = &s->stat_shared[entry];
520 struct dm_stat_percpu *p;
521
522 /*
523 * For strict correctness we should use local_irq_save/restore
524 * instead of preempt_disable/enable.
525 *
526 * preempt_disable/enable is racy if the driver finishes bios
527 * from non-interrupt context as well as from interrupt context
528 * or from more different interrupts.
529 *
530 * On 64-bit architectures the race only results in not counting some
531 * events, so it is acceptable. On 32-bit architectures the race could
532 * cause the counter going off by 2^32, so we need to do proper locking
533 * there.
534 *
535 * part_stat_lock()/part_stat_unlock() have this race too.
536 */
537 #if BITS_PER_LONG == 32
538 unsigned long flags;
539 local_irq_save(flags);
540 #else
541 preempt_disable();
542 #endif
543 p = &s->stat_percpu[smp_processor_id()][entry];
544
545 if (!end) {
546 dm_stat_round(s, shared, p);
547 atomic_inc(&shared->in_flight[idx]);
548 } else {
549 unsigned long long duration;
550 dm_stat_round(s, shared, p);
551 atomic_dec(&shared->in_flight[idx]);
552 p->sectors[idx] += len;
553 p->ios[idx] += 1;
554 p->merges[idx] += stats_aux->merged;
555 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
556 p->ticks[idx] += duration_jiffies;
557 duration = jiffies_to_msecs(duration_jiffies);
558 } else {
559 p->ticks[idx] += stats_aux->duration_ns;
560 duration = stats_aux->duration_ns;
561 }
562 if (s->n_histogram_entries) {
563 unsigned lo = 0, hi = s->n_histogram_entries + 1;
564 while (lo + 1 < hi) {
565 unsigned mid = (lo + hi) / 2;
566 if (s->histogram_boundaries[mid - 1] > duration) {
567 hi = mid;
568 } else {
569 lo = mid;
570 }
571
572 }
573 p->histogram[lo]++;
574 }
575 }
576
577 #if BITS_PER_LONG == 32
578 local_irq_restore(flags);
579 #else
580 preempt_enable();
581 #endif
582 }
583
584 static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
585 sector_t bi_sector, sector_t end_sector,
586 bool end, unsigned long duration_jiffies,
587 struct dm_stats_aux *stats_aux)
588 {
589 sector_t rel_sector, offset, todo, fragment_len;
590 size_t entry;
591
592 if (end_sector <= s->start || bi_sector >= s->end)
593 return;
594 if (unlikely(bi_sector < s->start)) {
595 rel_sector = 0;
596 todo = end_sector - s->start;
597 } else {
598 rel_sector = bi_sector - s->start;
599 todo = end_sector - bi_sector;
600 }
601 if (unlikely(end_sector > s->end))
602 todo -= (end_sector - s->end);
603
604 offset = dm_sector_div64(rel_sector, s->step);
605 entry = rel_sector;
606 do {
607 if (WARN_ON_ONCE(entry >= s->n_entries)) {
608 DMCRIT("Invalid area access in region id %d", s->id);
609 return;
610 }
611 fragment_len = todo;
612 if (fragment_len > s->step - offset)
613 fragment_len = s->step - offset;
614 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
615 stats_aux, end, duration_jiffies);
616 todo -= fragment_len;
617 entry++;
618 offset = 0;
619 } while (unlikely(todo != 0));
620 }
621
622 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
623 sector_t bi_sector, unsigned bi_sectors, bool end,
624 unsigned long duration_jiffies,
625 struct dm_stats_aux *stats_aux)
626 {
627 struct dm_stat *s;
628 sector_t end_sector;
629 struct dm_stats_last_position *last;
630 bool got_precise_time;
631
632 if (unlikely(!bi_sectors))
633 return;
634
635 end_sector = bi_sector + bi_sectors;
636
637 if (!end) {
638 /*
639 * A race condition can at worst result in the merged flag being
640 * misrepresented, so we don't have to disable preemption here.
641 */
642 last = raw_cpu_ptr(stats->last);
643 stats_aux->merged =
644 (bi_sector == (READ_ONCE(last->last_sector) &&
645 ((bi_rw == WRITE) ==
646 (READ_ONCE(last->last_rw) == WRITE))
647 ));
648 WRITE_ONCE(last->last_sector, end_sector);
649 WRITE_ONCE(last->last_rw, bi_rw);
650 }
651
652 rcu_read_lock();
653
654 got_precise_time = false;
655 list_for_each_entry_rcu(s, &stats->list, list_entry) {
656 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
657 if (!end)
658 stats_aux->duration_ns = ktime_to_ns(ktime_get());
659 else
660 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
661 got_precise_time = true;
662 }
663 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
664 }
665
666 rcu_read_unlock();
667 }
668
669 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
670 struct dm_stat *s, size_t x)
671 {
672 int cpu;
673 struct dm_stat_percpu *p;
674
675 local_irq_disable();
676 p = &s->stat_percpu[smp_processor_id()][x];
677 dm_stat_round(s, shared, p);
678 local_irq_enable();
679
680 shared->tmp.sectors[READ] = 0;
681 shared->tmp.sectors[WRITE] = 0;
682 shared->tmp.ios[READ] = 0;
683 shared->tmp.ios[WRITE] = 0;
684 shared->tmp.merges[READ] = 0;
685 shared->tmp.merges[WRITE] = 0;
686 shared->tmp.ticks[READ] = 0;
687 shared->tmp.ticks[WRITE] = 0;
688 shared->tmp.io_ticks[READ] = 0;
689 shared->tmp.io_ticks[WRITE] = 0;
690 shared->tmp.io_ticks_total = 0;
691 shared->tmp.time_in_queue = 0;
692
693 if (s->n_histogram_entries)
694 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
695
696 for_each_possible_cpu(cpu) {
697 p = &s->stat_percpu[cpu][x];
698 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
699 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
700 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
701 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
702 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
703 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
704 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
705 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
706 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
707 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
708 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
709 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
710 if (s->n_histogram_entries) {
711 unsigned i;
712 for (i = 0; i < s->n_histogram_entries + 1; i++)
713 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
714 }
715 }
716 }
717
718 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
719 bool init_tmp_percpu_totals)
720 {
721 size_t x;
722 struct dm_stat_shared *shared;
723 struct dm_stat_percpu *p;
724
725 for (x = idx_start; x < idx_end; x++) {
726 shared = &s->stat_shared[x];
727 if (init_tmp_percpu_totals)
728 __dm_stat_init_temporary_percpu_totals(shared, s, x);
729 local_irq_disable();
730 p = &s->stat_percpu[smp_processor_id()][x];
731 p->sectors[READ] -= shared->tmp.sectors[READ];
732 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
733 p->ios[READ] -= shared->tmp.ios[READ];
734 p->ios[WRITE] -= shared->tmp.ios[WRITE];
735 p->merges[READ] -= shared->tmp.merges[READ];
736 p->merges[WRITE] -= shared->tmp.merges[WRITE];
737 p->ticks[READ] -= shared->tmp.ticks[READ];
738 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
739 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
740 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
741 p->io_ticks_total -= shared->tmp.io_ticks_total;
742 p->time_in_queue -= shared->tmp.time_in_queue;
743 local_irq_enable();
744 if (s->n_histogram_entries) {
745 unsigned i;
746 for (i = 0; i < s->n_histogram_entries + 1; i++) {
747 local_irq_disable();
748 p = &s->stat_percpu[smp_processor_id()][x];
749 p->histogram[i] -= shared->tmp.histogram[i];
750 local_irq_enable();
751 }
752 }
753 }
754 }
755
756 static int dm_stats_clear(struct dm_stats *stats, int id)
757 {
758 struct dm_stat *s;
759
760 mutex_lock(&stats->mutex);
761
762 s = __dm_stats_find(stats, id);
763 if (!s) {
764 mutex_unlock(&stats->mutex);
765 return -ENOENT;
766 }
767
768 __dm_stat_clear(s, 0, s->n_entries, true);
769
770 mutex_unlock(&stats->mutex);
771
772 return 1;
773 }
774
775 /*
776 * This is like jiffies_to_msec, but works for 64-bit values.
777 */
778 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
779 {
780 unsigned long long result;
781 unsigned mult;
782
783 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
784 return j;
785
786 result = 0;
787 if (j)
788 result = jiffies_to_msecs(j & 0x3fffff);
789 if (j >= 1 << 22) {
790 mult = jiffies_to_msecs(1 << 22);
791 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
792 }
793 if (j >= 1ULL << 44)
794 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
795
796 return result;
797 }
798
799 static int dm_stats_print(struct dm_stats *stats, int id,
800 size_t idx_start, size_t idx_len,
801 bool clear, char *result, unsigned maxlen)
802 {
803 unsigned sz = 0;
804 struct dm_stat *s;
805 size_t x;
806 sector_t start, end, step;
807 size_t idx_end;
808 struct dm_stat_shared *shared;
809
810 /*
811 * Output format:
812 * <start_sector>+<length> counters
813 */
814
815 mutex_lock(&stats->mutex);
816
817 s = __dm_stats_find(stats, id);
818 if (!s) {
819 mutex_unlock(&stats->mutex);
820 return -ENOENT;
821 }
822
823 idx_end = idx_start + idx_len;
824 if (idx_end < idx_start ||
825 idx_end > s->n_entries)
826 idx_end = s->n_entries;
827
828 if (idx_start > idx_end)
829 idx_start = idx_end;
830
831 step = s->step;
832 start = s->start + (step * idx_start);
833
834 for (x = idx_start; x < idx_end; x++, start = end) {
835 shared = &s->stat_shared[x];
836 end = start + step;
837 if (unlikely(end > s->end))
838 end = s->end;
839
840 __dm_stat_init_temporary_percpu_totals(shared, s, x);
841
842 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
843 (unsigned long long)start,
844 (unsigned long long)step,
845 shared->tmp.ios[READ],
846 shared->tmp.merges[READ],
847 shared->tmp.sectors[READ],
848 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
849 shared->tmp.ios[WRITE],
850 shared->tmp.merges[WRITE],
851 shared->tmp.sectors[WRITE],
852 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
853 dm_stat_in_flight(shared),
854 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
855 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
856 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
857 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
858 if (s->n_histogram_entries) {
859 unsigned i;
860 for (i = 0; i < s->n_histogram_entries + 1; i++) {
861 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
862 }
863 }
864 DMEMIT("\n");
865
866 if (unlikely(sz + 1 >= maxlen))
867 goto buffer_overflow;
868 }
869
870 if (clear)
871 __dm_stat_clear(s, idx_start, idx_end, false);
872
873 buffer_overflow:
874 mutex_unlock(&stats->mutex);
875
876 return 1;
877 }
878
879 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
880 {
881 struct dm_stat *s;
882 const char *new_aux_data;
883
884 mutex_lock(&stats->mutex);
885
886 s = __dm_stats_find(stats, id);
887 if (!s) {
888 mutex_unlock(&stats->mutex);
889 return -ENOENT;
890 }
891
892 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
893 if (!new_aux_data) {
894 mutex_unlock(&stats->mutex);
895 return -ENOMEM;
896 }
897
898 kfree(s->aux_data);
899 s->aux_data = new_aux_data;
900
901 mutex_unlock(&stats->mutex);
902
903 return 0;
904 }
905
906 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
907 unsigned long long **histogram_boundaries)
908 {
909 const char *q;
910 unsigned n;
911 unsigned long long last;
912
913 *n_histogram_entries = 1;
914 for (q = h; *q; q++)
915 if (*q == ',')
916 (*n_histogram_entries)++;
917
918 *histogram_boundaries = kmalloc_array(*n_histogram_entries,
919 sizeof(unsigned long long),
920 GFP_KERNEL);
921 if (!*histogram_boundaries)
922 return -ENOMEM;
923
924 n = 0;
925 last = 0;
926 while (1) {
927 unsigned long long hi;
928 int s;
929 char ch;
930 s = sscanf(h, "%llu%c", &hi, &ch);
931 if (!s || (s == 2 && ch != ','))
932 return -EINVAL;
933 if (hi <= last)
934 return -EINVAL;
935 last = hi;
936 (*histogram_boundaries)[n] = hi;
937 if (s == 1)
938 return 0;
939 h = strchr(h, ',') + 1;
940 n++;
941 }
942 }
943
944 static int message_stats_create(struct mapped_device *md,
945 unsigned argc, char **argv,
946 char *result, unsigned maxlen)
947 {
948 int r;
949 int id;
950 char dummy;
951 unsigned long long start, end, len, step;
952 unsigned divisor;
953 const char *program_id, *aux_data;
954 unsigned stat_flags = 0;
955
956 unsigned n_histogram_entries = 0;
957 unsigned long long *histogram_boundaries = NULL;
958
959 struct dm_arg_set as, as_backup;
960 const char *a;
961 unsigned feature_args;
962
963 /*
964 * Input format:
965 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
966 */
967
968 if (argc < 3)
969 goto ret_einval;
970
971 as.argc = argc;
972 as.argv = argv;
973 dm_consume_args(&as, 1);
974
975 a = dm_shift_arg(&as);
976 if (!strcmp(a, "-")) {
977 start = 0;
978 len = dm_get_size(md);
979 if (!len)
980 len = 1;
981 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
982 start != (sector_t)start || len != (sector_t)len)
983 goto ret_einval;
984
985 end = start + len;
986 if (start >= end)
987 goto ret_einval;
988
989 a = dm_shift_arg(&as);
990 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
991 if (!divisor)
992 return -EINVAL;
993 step = end - start;
994 if (do_div(step, divisor))
995 step++;
996 if (!step)
997 step = 1;
998 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
999 step != (sector_t)step || !step)
1000 goto ret_einval;
1001
1002 as_backup = as;
1003 a = dm_shift_arg(&as);
1004 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1005 while (feature_args--) {
1006 a = dm_shift_arg(&as);
1007 if (!a)
1008 goto ret_einval;
1009 if (!strcasecmp(a, "precise_timestamps"))
1010 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1011 else if (!strncasecmp(a, "histogram:", 10)) {
1012 if (n_histogram_entries)
1013 goto ret_einval;
1014 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1015 goto ret;
1016 } else
1017 goto ret_einval;
1018 }
1019 } else {
1020 as = as_backup;
1021 }
1022
1023 program_id = "-";
1024 aux_data = "-";
1025
1026 a = dm_shift_arg(&as);
1027 if (a)
1028 program_id = a;
1029
1030 a = dm_shift_arg(&as);
1031 if (a)
1032 aux_data = a;
1033
1034 if (as.argc)
1035 goto ret_einval;
1036
1037 /*
1038 * If a buffer overflow happens after we created the region,
1039 * it's too late (the userspace would retry with a larger
1040 * buffer, but the region id that caused the overflow is already
1041 * leaked). So we must detect buffer overflow in advance.
1042 */
1043 snprintf(result, maxlen, "%d", INT_MAX);
1044 if (dm_message_test_buffer_overflow(result, maxlen)) {
1045 r = 1;
1046 goto ret;
1047 }
1048
1049 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1050 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1051 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1052 if (id < 0) {
1053 r = id;
1054 goto ret;
1055 }
1056
1057 snprintf(result, maxlen, "%d", id);
1058
1059 r = 1;
1060 goto ret;
1061
1062 ret_einval:
1063 r = -EINVAL;
1064 ret:
1065 kfree(histogram_boundaries);
1066 return r;
1067 }
1068
1069 static int message_stats_delete(struct mapped_device *md,
1070 unsigned argc, char **argv)
1071 {
1072 int id;
1073 char dummy;
1074
1075 if (argc != 2)
1076 return -EINVAL;
1077
1078 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1079 return -EINVAL;
1080
1081 return dm_stats_delete(dm_get_stats(md), id);
1082 }
1083
1084 static int message_stats_clear(struct mapped_device *md,
1085 unsigned argc, char **argv)
1086 {
1087 int id;
1088 char dummy;
1089
1090 if (argc != 2)
1091 return -EINVAL;
1092
1093 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1094 return -EINVAL;
1095
1096 return dm_stats_clear(dm_get_stats(md), id);
1097 }
1098
1099 static int message_stats_list(struct mapped_device *md,
1100 unsigned argc, char **argv,
1101 char *result, unsigned maxlen)
1102 {
1103 int r;
1104 const char *program = NULL;
1105
1106 if (argc < 1 || argc > 2)
1107 return -EINVAL;
1108
1109 if (argc > 1) {
1110 program = kstrdup(argv[1], GFP_KERNEL);
1111 if (!program)
1112 return -ENOMEM;
1113 }
1114
1115 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1116
1117 kfree(program);
1118
1119 return r;
1120 }
1121
1122 static int message_stats_print(struct mapped_device *md,
1123 unsigned argc, char **argv, bool clear,
1124 char *result, unsigned maxlen)
1125 {
1126 int id;
1127 char dummy;
1128 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1129
1130 if (argc != 2 && argc != 4)
1131 return -EINVAL;
1132
1133 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1134 return -EINVAL;
1135
1136 if (argc > 3) {
1137 if (strcmp(argv[2], "-") &&
1138 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1139 return -EINVAL;
1140 if (strcmp(argv[3], "-") &&
1141 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1142 return -EINVAL;
1143 }
1144
1145 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1146 result, maxlen);
1147 }
1148
1149 static int message_stats_set_aux(struct mapped_device *md,
1150 unsigned argc, char **argv)
1151 {
1152 int id;
1153 char dummy;
1154
1155 if (argc != 3)
1156 return -EINVAL;
1157
1158 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1159 return -EINVAL;
1160
1161 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1162 }
1163
1164 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1165 char *result, unsigned maxlen)
1166 {
1167 int r;
1168
1169 /* All messages here must start with '@' */
1170 if (!strcasecmp(argv[0], "@stats_create"))
1171 r = message_stats_create(md, argc, argv, result, maxlen);
1172 else if (!strcasecmp(argv[0], "@stats_delete"))
1173 r = message_stats_delete(md, argc, argv);
1174 else if (!strcasecmp(argv[0], "@stats_clear"))
1175 r = message_stats_clear(md, argc, argv);
1176 else if (!strcasecmp(argv[0], "@stats_list"))
1177 r = message_stats_list(md, argc, argv, result, maxlen);
1178 else if (!strcasecmp(argv[0], "@stats_print"))
1179 r = message_stats_print(md, argc, argv, false, result, maxlen);
1180 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1181 r = message_stats_print(md, argc, argv, true, result, maxlen);
1182 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1183 r = message_stats_set_aux(md, argc, argv);
1184 else
1185 return 2; /* this wasn't a stats message */
1186
1187 if (r == -EINVAL)
1188 DMWARN("Invalid parameters for message %s", argv[0]);
1189
1190 return r;
1191 }
1192
1193 int __init dm_statistics_init(void)
1194 {
1195 shared_memory_amount = 0;
1196 dm_stat_need_rcu_barrier = 0;
1197 return 0;
1198 }
1199
1200 void dm_statistics_exit(void)
1201 {
1202 if (dm_stat_need_rcu_barrier)
1203 rcu_barrier();
1204 if (WARN_ON(shared_memory_amount))
1205 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1206 }
1207
1208 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1209 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
Linux with added FPC-III support