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Linux 4.2.1
[linux/fpc-iii.git] / drivers / md / dm-stats.c
blob8289804ccd998a1d4d9be9fce2a32bd4bfa6cad8
1 #include <linux/errno.h>
2 #include <linux/numa.h>
3 #include <linux/slab.h>
4 #include <linux/rculist.h>
5 #include <linux/threads.h>
6 #include <linux/preempt.h>
7 #include <linux/irqflags.h>
8 #include <linux/vmalloc.h>
9 #include <linux/mm.h>
10 #include <linux/module.h>
11 #include <linux/device-mapper.h>
12
13 #include "dm.h"
14 #include "dm-stats.h"
15
16 #define DM_MSG_PREFIX "stats"
17
18 static int dm_stat_need_rcu_barrier;
19
20 /*
21 * Using 64-bit values to avoid overflow (which is a
22 * problem that block/genhd.c's IO accounting has).
23 */
24 struct dm_stat_percpu {
25 unsigned long long sectors[2];
26 unsigned long long ios[2];
27 unsigned long long merges[2];
28 unsigned long long ticks[2];
29 unsigned long long io_ticks[2];
30 unsigned long long io_ticks_total;
31 unsigned long long time_in_queue;
32 unsigned long long *histogram;
33 };
34
35 struct dm_stat_shared {
36 atomic_t in_flight[2];
37 unsigned long long stamp;
38 struct dm_stat_percpu tmp;
39 };
40
41 struct dm_stat {
42 struct list_head list_entry;
43 int id;
44 unsigned stat_flags;
45 size_t n_entries;
46 sector_t start;
47 sector_t end;
48 sector_t step;
49 unsigned n_histogram_entries;
50 unsigned long long *histogram_boundaries;
51 const char *program_id;
52 const char *aux_data;
53 struct rcu_head rcu_head;
54 size_t shared_alloc_size;
55 size_t percpu_alloc_size;
56 size_t histogram_alloc_size;
57 struct dm_stat_percpu *stat_percpu[NR_CPUS];
58 struct dm_stat_shared stat_shared[0];
59 };
60
61 #define STAT_PRECISE_TIMESTAMPS 1
62
63 struct dm_stats_last_position {
64 sector_t last_sector;
65 unsigned last_rw;
66 };
67
68 /*
69 * A typo on the command line could possibly make the kernel run out of memory
70 * and crash. To prevent the crash we account all used memory. We fail if we
71 * exhaust 1/4 of all memory or 1/2 of vmalloc space.
72 */
73 #define DM_STATS_MEMORY_FACTOR 4
74 #define DM_STATS_VMALLOC_FACTOR 2
75
76 static DEFINE_SPINLOCK(shared_memory_lock);
77
78 static unsigned long shared_memory_amount;
79
80 static bool __check_shared_memory(size_t alloc_size)
81 {
82 size_t a;
83
84 a = shared_memory_amount + alloc_size;
85 if (a < shared_memory_amount)
86 return false;
87 if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR)
88 return false;
89 #ifdef CONFIG_MMU
90 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
91 return false;
92 #endif
93 return true;
94 }
95
96 static bool check_shared_memory(size_t alloc_size)
97 {
98 bool ret;
99
100 spin_lock_irq(&shared_memory_lock);
101
102 ret = __check_shared_memory(alloc_size);
103
104 spin_unlock_irq(&shared_memory_lock);
105
106 return ret;
107 }
108
109 static bool claim_shared_memory(size_t alloc_size)
110 {
111 spin_lock_irq(&shared_memory_lock);
112
113 if (!__check_shared_memory(alloc_size)) {
114 spin_unlock_irq(&shared_memory_lock);
115 return false;
116 }
117
118 shared_memory_amount += alloc_size;
119
120 spin_unlock_irq(&shared_memory_lock);
121
122 return true;
123 }
124
125 static void free_shared_memory(size_t alloc_size)
126 {
127 unsigned long flags;
128
129 spin_lock_irqsave(&shared_memory_lock, flags);
130
131 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
132 spin_unlock_irqrestore(&shared_memory_lock, flags);
133 DMCRIT("Memory usage accounting bug.");
134 return;
135 }
136
137 shared_memory_amount -= alloc_size;
138
139 spin_unlock_irqrestore(&shared_memory_lock, flags);
140 }
141
142 static void *dm_kvzalloc(size_t alloc_size, int node)
143 {
144 void *p;
145
146 if (!claim_shared_memory(alloc_size))
147 return NULL;
148
149 if (alloc_size <= KMALLOC_MAX_SIZE) {
150 p = kzalloc_node(alloc_size, GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN, node);
151 if (p)
152 return p;
153 }
154 p = vzalloc_node(alloc_size, node);
155 if (p)
156 return p;
157
158 free_shared_memory(alloc_size);
159
160 return NULL;
161 }
162
163 static void dm_kvfree(void *ptr, size_t alloc_size)
164 {
165 if (!ptr)
166 return;
167
168 free_shared_memory(alloc_size);
169
170 kvfree(ptr);
171 }
172
173 static void dm_stat_free(struct rcu_head *head)
174 {
175 int cpu;
176 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
177
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
188 static 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
194 void 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->last = alloc_percpu(struct dm_stats_last_position);
202 for_each_possible_cpu(cpu) {
203 last = per_cpu_ptr(stats->last, cpu);
204 last->last_sector = (sector_t)ULLONG_MAX;
205 last->last_rw = UINT_MAX;
206 }
207 }
208
209 void dm_stats_cleanup(struct dm_stats *stats)
210 {
211 size_t ni;
212 struct dm_stat *s;
213 struct dm_stat_shared *shared;
214
215 while (!list_empty(&stats->list)) {
216 s = container_of(stats->list.next, struct dm_stat, list_entry);
217 list_del(&s->list_entry);
218 for (ni = 0; ni < s->n_entries; ni++) {
219 shared = &s->stat_shared[ni];
220 if (WARN_ON(dm_stat_in_flight(shared))) {
221 DMCRIT("leaked in-flight counter at index %lu "
222 "(start %llu, end %llu, step %llu): reads %d, writes %d",
223 (unsigned long)ni,
224 (unsigned long long)s->start,
225 (unsigned long long)s->end,
226 (unsigned long long)s->step,
227 atomic_read(&shared->in_flight[READ]),
228 atomic_read(&shared->in_flight[WRITE]));
229 }
230 }
231 dm_stat_free(&s->rcu_head);
232 }
233 free_percpu(stats->last);
234 }
235
236 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
237 sector_t step, unsigned stat_flags,
238 unsigned n_histogram_entries,
239 unsigned long long *histogram_boundaries,
240 const char *program_id, const char *aux_data,
241 void (*suspend_callback)(struct mapped_device *),
242 void (*resume_callback)(struct mapped_device *),
243 struct mapped_device *md)
244 {
245 struct list_head *l;
246 struct dm_stat *s, *tmp_s;
247 sector_t n_entries;
248 size_t ni;
249 size_t shared_alloc_size;
250 size_t percpu_alloc_size;
251 size_t histogram_alloc_size;
252 struct dm_stat_percpu *p;
253 int cpu;
254 int ret_id;
255 int r;
256
257 if (end < start || !step)
258 return -EINVAL;
259
260 n_entries = end - start;
261 if (dm_sector_div64(n_entries, step))
262 n_entries++;
263
264 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
265 return -EOVERFLOW;
266
267 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
268 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
269 return -EOVERFLOW;
270
271 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
272 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
273 return -EOVERFLOW;
274
275 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
276 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
277 return -EOVERFLOW;
278
279 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
280 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
281 return -ENOMEM;
282
283 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
284 if (!s)
285 return -ENOMEM;
286
287 s->stat_flags = stat_flags;
288 s->n_entries = n_entries;
289 s->start = start;
290 s->end = end;
291 s->step = step;
292 s->shared_alloc_size = shared_alloc_size;
293 s->percpu_alloc_size = percpu_alloc_size;
294 s->histogram_alloc_size = histogram_alloc_size;
295
296 s->n_histogram_entries = n_histogram_entries;
297 s->histogram_boundaries = kmemdup(histogram_boundaries,
298 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
299 if (!s->histogram_boundaries) {
300 r = -ENOMEM;
301 goto out;
302 }
303
304 s->program_id = kstrdup(program_id, GFP_KERNEL);
305 if (!s->program_id) {
306 r = -ENOMEM;
307 goto out;
308 }
309 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
310 if (!s->aux_data) {
311 r = -ENOMEM;
312 goto out;
313 }
314
315 for (ni = 0; ni < n_entries; ni++) {
316 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
317 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
318 }
319
320 if (s->n_histogram_entries) {
321 unsigned long long *hi;
322 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
323 if (!hi) {
324 r = -ENOMEM;
325 goto out;
326 }
327 for (ni = 0; ni < n_entries; ni++) {
328 s->stat_shared[ni].tmp.histogram = hi;
329 hi += s->n_histogram_entries + 1;
330 }
331 }
332
333 for_each_possible_cpu(cpu) {
334 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
335 if (!p) {
336 r = -ENOMEM;
337 goto out;
338 }
339 s->stat_percpu[cpu] = p;
340 if (s->n_histogram_entries) {
341 unsigned long long *hi;
342 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
343 if (!hi) {
344 r = -ENOMEM;
345 goto out;
346 }
347 for (ni = 0; ni < n_entries; ni++) {
348 p[ni].histogram = hi;
349 hi += s->n_histogram_entries + 1;
350 }
351 }
352 }
353
354 /*
355 * Suspend/resume to make sure there is no i/o in flight,
356 * so that newly created statistics will be exact.
357 *
358 * (note: we couldn't suspend earlier because we must not
359 * allocate memory while suspended)
360 */
361 suspend_callback(md);
362
363 mutex_lock(&stats->mutex);
364 s->id = 0;
365 list_for_each(l, &stats->list) {
366 tmp_s = container_of(l, struct dm_stat, list_entry);
367 if (WARN_ON(tmp_s->id < s->id)) {
368 r = -EINVAL;
369 goto out_unlock_resume;
370 }
371 if (tmp_s->id > s->id)
372 break;
373 if (unlikely(s->id == INT_MAX)) {
374 r = -ENFILE;
375 goto out_unlock_resume;
376 }
377 s->id++;
378 }
379 ret_id = s->id;
380 list_add_tail_rcu(&s->list_entry, l);
381 mutex_unlock(&stats->mutex);
382
383 resume_callback(md);
384
385 return ret_id;
386
387 out_unlock_resume:
388 mutex_unlock(&stats->mutex);
389 resume_callback(md);
390 out:
391 dm_stat_free(&s->rcu_head);
392 return r;
393 }
394
395 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
396 {
397 struct dm_stat *s;
398
399 list_for_each_entry(s, &stats->list, list_entry) {
400 if (s->id > id)
401 break;
402 if (s->id == id)
403 return s;
404 }
405
406 return NULL;
407 }
408
409 static int dm_stats_delete(struct dm_stats *stats, int id)
410 {
411 struct dm_stat *s;
412 int cpu;
413
414 mutex_lock(&stats->mutex);
415
416 s = __dm_stats_find(stats, id);
417 if (!s) {
418 mutex_unlock(&stats->mutex);
419 return -ENOENT;
420 }
421
422 list_del_rcu(&s->list_entry);
423 mutex_unlock(&stats->mutex);
424
425 /*
426 * vfree can't be called from RCU callback
427 */
428 for_each_possible_cpu(cpu)
429 if (is_vmalloc_addr(s->stat_percpu) ||
430 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
431 goto do_sync_free;
432 if (is_vmalloc_addr(s) ||
433 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
434 do_sync_free:
435 synchronize_rcu_expedited();
436 dm_stat_free(&s->rcu_head);
437 } else {
438 ACCESS_ONCE(dm_stat_need_rcu_barrier) = 1;
439 call_rcu(&s->rcu_head, dm_stat_free);
440 }
441 return 0;
442 }
443
444 static int dm_stats_list(struct dm_stats *stats, const char *program,
445 char *result, unsigned maxlen)
446 {
447 struct dm_stat *s;
448 sector_t len;
449 unsigned sz = 0;
450
451 /*
452 * Output format:
453 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
454 */
455
456 mutex_lock(&stats->mutex);
457 list_for_each_entry(s, &stats->list, list_entry) {
458 if (!program || !strcmp(program, s->program_id)) {
459 len = s->end - s->start;
460 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
461 (unsigned long long)s->start,
462 (unsigned long long)len,
463 (unsigned long long)s->step,
464 s->program_id,
465 s->aux_data);
466 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
467 DMEMIT(" precise_timestamps");
468 if (s->n_histogram_entries) {
469 unsigned i;
470 DMEMIT(" histogram:");
471 for (i = 0; i < s->n_histogram_entries; i++) {
472 if (i)
473 DMEMIT(",");
474 DMEMIT("%llu", s->histogram_boundaries[i]);
475 }
476 }
477 DMEMIT("\n");
478 }
479 }
480 mutex_unlock(&stats->mutex);
481
482 return 1;
483 }
484
485 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
486 struct dm_stat_percpu *p)
487 {
488 /*
489 * This is racy, but so is part_round_stats_single.
490 */
491 unsigned long long now, difference;
492 unsigned in_flight_read, in_flight_write;
493
494 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
495 now = jiffies;
496 else
497 now = ktime_to_ns(ktime_get());
498
499 difference = now - shared->stamp;
500 if (!difference)
501 return;
502
503 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
504 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
505 if (in_flight_read)
506 p->io_ticks[READ] += difference;
507 if (in_flight_write)
508 p->io_ticks[WRITE] += difference;
509 if (in_flight_read + in_flight_write) {
510 p->io_ticks_total += difference;
511 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
512 }
513 shared->stamp = now;
514 }
515
516 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
517 unsigned long bi_rw, sector_t len,
518 struct dm_stats_aux *stats_aux, bool end,
519 unsigned long duration_jiffies)
520 {
521 unsigned long idx = bi_rw & REQ_WRITE;
522 struct dm_stat_shared *shared = &s->stat_shared[entry];
523 struct dm_stat_percpu *p;
524
525 /*
526 * For strict correctness we should use local_irq_save/restore
527 * instead of preempt_disable/enable.
528 *
529 * preempt_disable/enable is racy if the driver finishes bios
530 * from non-interrupt context as well as from interrupt context
531 * or from more different interrupts.
532 *
533 * On 64-bit architectures the race only results in not counting some
534 * events, so it is acceptable. On 32-bit architectures the race could
535 * cause the counter going off by 2^32, so we need to do proper locking
536 * there.
537 *
538 * part_stat_lock()/part_stat_unlock() have this race too.
539 */
540 #if BITS_PER_LONG == 32
541 unsigned long flags;
542 local_irq_save(flags);
543 #else
544 preempt_disable();
545 #endif
546 p = &s->stat_percpu[smp_processor_id()][entry];
547
548 if (!end) {
549 dm_stat_round(s, shared, p);
550 atomic_inc(&shared->in_flight[idx]);
551 } else {
552 unsigned long long duration;
553 dm_stat_round(s, shared, p);
554 atomic_dec(&shared->in_flight[idx]);
555 p->sectors[idx] += len;
556 p->ios[idx] += 1;
557 p->merges[idx] += stats_aux->merged;
558 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
559 p->ticks[idx] += duration_jiffies;
560 duration = jiffies_to_msecs(duration_jiffies);
561 } else {
562 p->ticks[idx] += stats_aux->duration_ns;
563 duration = stats_aux->duration_ns;
564 }
565 if (s->n_histogram_entries) {
566 unsigned lo = 0, hi = s->n_histogram_entries + 1;
567 while (lo + 1 < hi) {
568 unsigned mid = (lo + hi) / 2;
569 if (s->histogram_boundaries[mid - 1] > duration) {
570 hi = mid;
571 } else {
572 lo = mid;
573 }
574
575 }
576 p->histogram[lo]++;
577 }
578 }
579
580 #if BITS_PER_LONG == 32
581 local_irq_restore(flags);
582 #else
583 preempt_enable();
584 #endif
585 }
586
587 static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw,
588 sector_t bi_sector, sector_t end_sector,
589 bool end, unsigned long duration_jiffies,
590 struct dm_stats_aux *stats_aux)
591 {
592 sector_t rel_sector, offset, todo, fragment_len;
593 size_t entry;
594
595 if (end_sector <= s->start || bi_sector >= s->end)
596 return;
597 if (unlikely(bi_sector < s->start)) {
598 rel_sector = 0;
599 todo = end_sector - s->start;
600 } else {
601 rel_sector = bi_sector - s->start;
602 todo = end_sector - bi_sector;
603 }
604 if (unlikely(end_sector > s->end))
605 todo -= (end_sector - s->end);
606
607 offset = dm_sector_div64(rel_sector, s->step);
608 entry = rel_sector;
609 do {
610 if (WARN_ON_ONCE(entry >= s->n_entries)) {
611 DMCRIT("Invalid area access in region id %d", s->id);
612 return;
613 }
614 fragment_len = todo;
615 if (fragment_len > s->step - offset)
616 fragment_len = s->step - offset;
617 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
618 stats_aux, end, duration_jiffies);
619 todo -= fragment_len;
620 entry++;
621 offset = 0;
622 } while (unlikely(todo != 0));
623 }
624
625 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
626 sector_t bi_sector, unsigned bi_sectors, bool end,
627 unsigned long duration_jiffies,
628 struct dm_stats_aux *stats_aux)
629 {
630 struct dm_stat *s;
631 sector_t end_sector;
632 struct dm_stats_last_position *last;
633 bool got_precise_time;
634
635 if (unlikely(!bi_sectors))
636 return;
637
638 end_sector = bi_sector + bi_sectors;
639
640 if (!end) {
641 /*
642 * A race condition can at worst result in the merged flag being
643 * misrepresented, so we don't have to disable preemption here.
644 */
645 last = raw_cpu_ptr(stats->last);
646 stats_aux->merged =
647 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
648 ((bi_rw & (REQ_WRITE | REQ_DISCARD)) ==
649 (ACCESS_ONCE(last->last_rw) & (REQ_WRITE | REQ_DISCARD)))
650 ));
651 ACCESS_ONCE(last->last_sector) = end_sector;
652 ACCESS_ONCE(last->last_rw) = bi_rw;
653 }
654
655 rcu_read_lock();
656
657 got_precise_time = false;
658 list_for_each_entry_rcu(s, &stats->list, list_entry) {
659 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
660 if (!end)
661 stats_aux->duration_ns = ktime_to_ns(ktime_get());
662 else
663 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
664 got_precise_time = true;
665 }
666 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
667 }
668
669 rcu_read_unlock();
670 }
671
672 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
673 struct dm_stat *s, size_t x)
674 {
675 int cpu;
676 struct dm_stat_percpu *p;
677
678 local_irq_disable();
679 p = &s->stat_percpu[smp_processor_id()][x];
680 dm_stat_round(s, shared, p);
681 local_irq_enable();
682
683 shared->tmp.sectors[READ] = 0;
684 shared->tmp.sectors[WRITE] = 0;
685 shared->tmp.ios[READ] = 0;
686 shared->tmp.ios[WRITE] = 0;
687 shared->tmp.merges[READ] = 0;
688 shared->tmp.merges[WRITE] = 0;
689 shared->tmp.ticks[READ] = 0;
690 shared->tmp.ticks[WRITE] = 0;
691 shared->tmp.io_ticks[READ] = 0;
692 shared->tmp.io_ticks[WRITE] = 0;
693 shared->tmp.io_ticks_total = 0;
694 shared->tmp.time_in_queue = 0;
695
696 if (s->n_histogram_entries)
697 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
698
699 for_each_possible_cpu(cpu) {
700 p = &s->stat_percpu[cpu][x];
701 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
702 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
703 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
704 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
705 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
706 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
707 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
708 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
709 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
710 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
711 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
712 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
713 if (s->n_histogram_entries) {
714 unsigned i;
715 for (i = 0; i < s->n_histogram_entries + 1; i++)
716 shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]);
717 }
718 }
719 }
720
721 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
722 bool init_tmp_percpu_totals)
723 {
724 size_t x;
725 struct dm_stat_shared *shared;
726 struct dm_stat_percpu *p;
727
728 for (x = idx_start; x < idx_end; x++) {
729 shared = &s->stat_shared[x];
730 if (init_tmp_percpu_totals)
731 __dm_stat_init_temporary_percpu_totals(shared, s, x);
732 local_irq_disable();
733 p = &s->stat_percpu[smp_processor_id()][x];
734 p->sectors[READ] -= shared->tmp.sectors[READ];
735 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
736 p->ios[READ] -= shared->tmp.ios[READ];
737 p->ios[WRITE] -= shared->tmp.ios[WRITE];
738 p->merges[READ] -= shared->tmp.merges[READ];
739 p->merges[WRITE] -= shared->tmp.merges[WRITE];
740 p->ticks[READ] -= shared->tmp.ticks[READ];
741 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
742 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
743 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
744 p->io_ticks_total -= shared->tmp.io_ticks_total;
745 p->time_in_queue -= shared->tmp.time_in_queue;
746 local_irq_enable();
747 if (s->n_histogram_entries) {
748 unsigned i;
749 for (i = 0; i < s->n_histogram_entries + 1; i++) {
750 local_irq_disable();
751 p = &s->stat_percpu[smp_processor_id()][x];
752 p->histogram[i] -= shared->tmp.histogram[i];
753 local_irq_enable();
754 }
755 }
756 }
757 }
758
759 static int dm_stats_clear(struct dm_stats *stats, int id)
760 {
761 struct dm_stat *s;
762
763 mutex_lock(&stats->mutex);
764
765 s = __dm_stats_find(stats, id);
766 if (!s) {
767 mutex_unlock(&stats->mutex);
768 return -ENOENT;
769 }
770
771 __dm_stat_clear(s, 0, s->n_entries, true);
772
773 mutex_unlock(&stats->mutex);
774
775 return 1;
776 }
777
778 /*
779 * This is like jiffies_to_msec, but works for 64-bit values.
780 */
781 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
782 {
783 unsigned long long result;
784 unsigned mult;
785
786 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
787 return j;
788
789 result = 0;
790 if (j)
791 result = jiffies_to_msecs(j & 0x3fffff);
792 if (j >= 1 << 22) {
793 mult = jiffies_to_msecs(1 << 22);
794 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
795 }
796 if (j >= 1ULL << 44)
797 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
798
799 return result;
800 }
801
802 static int dm_stats_print(struct dm_stats *stats, int id,
803 size_t idx_start, size_t idx_len,
804 bool clear, char *result, unsigned maxlen)
805 {
806 unsigned sz = 0;
807 struct dm_stat *s;
808 size_t x;
809 sector_t start, end, step;
810 size_t idx_end;
811 struct dm_stat_shared *shared;
812
813 /*
814 * Output format:
815 * <start_sector>+<length> counters
816 */
817
818 mutex_lock(&stats->mutex);
819
820 s = __dm_stats_find(stats, id);
821 if (!s) {
822 mutex_unlock(&stats->mutex);
823 return -ENOENT;
824 }
825
826 idx_end = idx_start + idx_len;
827 if (idx_end < idx_start ||
828 idx_end > s->n_entries)
829 idx_end = s->n_entries;
830
831 if (idx_start > idx_end)
832 idx_start = idx_end;
833
834 step = s->step;
835 start = s->start + (step * idx_start);
836
837 for (x = idx_start; x < idx_end; x++, start = end) {
838 shared = &s->stat_shared[x];
839 end = start + step;
840 if (unlikely(end > s->end))
841 end = s->end;
842
843 __dm_stat_init_temporary_percpu_totals(shared, s, x);
844
845 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
846 (unsigned long long)start,
847 (unsigned long long)step,
848 shared->tmp.ios[READ],
849 shared->tmp.merges[READ],
850 shared->tmp.sectors[READ],
851 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
852 shared->tmp.ios[WRITE],
853 shared->tmp.merges[WRITE],
854 shared->tmp.sectors[WRITE],
855 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
856 dm_stat_in_flight(shared),
857 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
858 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
859 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
860 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
861 if (s->n_histogram_entries) {
862 unsigned i;
863 for (i = 0; i < s->n_histogram_entries + 1; i++) {
864 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
865 }
866 }
867 DMEMIT("\n");
868
869 if (unlikely(sz + 1 >= maxlen))
870 goto buffer_overflow;
871 }
872
873 if (clear)
874 __dm_stat_clear(s, idx_start, idx_end, false);
875
876 buffer_overflow:
877 mutex_unlock(&stats->mutex);
878
879 return 1;
880 }
881
882 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
883 {
884 struct dm_stat *s;
885 const char *new_aux_data;
886
887 mutex_lock(&stats->mutex);
888
889 s = __dm_stats_find(stats, id);
890 if (!s) {
891 mutex_unlock(&stats->mutex);
892 return -ENOENT;
893 }
894
895 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
896 if (!new_aux_data) {
897 mutex_unlock(&stats->mutex);
898 return -ENOMEM;
899 }
900
901 kfree(s->aux_data);
902 s->aux_data = new_aux_data;
903
904 mutex_unlock(&stats->mutex);
905
906 return 0;
907 }
908
909 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
910 unsigned long long **histogram_boundaries)
911 {
912 const char *q;
913 unsigned n;
914 unsigned long long last;
915
916 *n_histogram_entries = 1;
917 for (q = h; *q; q++)
918 if (*q == ',')
919 (*n_histogram_entries)++;
920
921 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
922 if (!*histogram_boundaries)
923 return -ENOMEM;
924
925 n = 0;
926 last = 0;
927 while (1) {
928 unsigned long long hi;
929 int s;
930 char ch;
931 s = sscanf(h, "%llu%c", &hi, &ch);
932 if (!s || (s == 2 && ch != ','))
933 return -EINVAL;
934 if (hi <= last)
935 return -EINVAL;
936 last = hi;
937 (*histogram_boundaries)[n] = hi;
938 if (s == 1)
939 return 0;
940 h = strchr(h, ',') + 1;
941 n++;
942 }
943 }
944
945 static int message_stats_create(struct mapped_device *md,
946 unsigned argc, char **argv,
947 char *result, unsigned maxlen)
948 {
949 int r;
950 int id;
951 char dummy;
952 unsigned long long start, end, len, step;
953 unsigned divisor;
954 const char *program_id, *aux_data;
955 unsigned stat_flags = 0;
956
957 unsigned n_histogram_entries = 0;
958 unsigned long long *histogram_boundaries = NULL;
959
960 struct dm_arg_set as, as_backup;
961 const char *a;
962 unsigned feature_args;
963
964 /*
965 * Input format:
966 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
967 */
968
969 if (argc < 3)
970 goto ret_einval;
971
972 as.argc = argc;
973 as.argv = argv;
974 dm_consume_args(&as, 1);
975
976 a = dm_shift_arg(&as);
977 if (!strcmp(a, "-")) {
978 start = 0;
979 len = dm_get_size(md);
980 if (!len)
981 len = 1;
982 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
983 start != (sector_t)start || len != (sector_t)len)
984 goto ret_einval;
985
986 end = start + len;
987 if (start >= end)
988 goto ret_einval;
989
990 a = dm_shift_arg(&as);
991 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
992 if (!divisor)
993 return -EINVAL;
994 step = end - start;
995 if (do_div(step, divisor))
996 step++;
997 if (!step)
998 step = 1;
999 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1000 step != (sector_t)step || !step)
1001 goto ret_einval;
1002
1003 as_backup = as;
1004 a = dm_shift_arg(&as);
1005 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1006 while (feature_args--) {
1007 a = dm_shift_arg(&as);
1008 if (!a)
1009 goto ret_einval;
1010 if (!strcasecmp(a, "precise_timestamps"))
1011 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1012 else if (!strncasecmp(a, "histogram:", 10)) {
1013 if (n_histogram_entries)
1014 goto ret_einval;
1015 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1016 goto ret;
1017 } else
1018 goto ret_einval;
1019 }
1020 } else {
1021 as = as_backup;
1022 }
1023
1024 program_id = "-";
1025 aux_data = "-";
1026
1027 a = dm_shift_arg(&as);
1028 if (a)
1029 program_id = a;
1030
1031 a = dm_shift_arg(&as);
1032 if (a)
1033 aux_data = a;
1034
1035 if (as.argc)
1036 goto ret_einval;
1037
1038 /*
1039 * If a buffer overflow happens after we created the region,
1040 * it's too late (the userspace would retry with a larger
1041 * buffer, but the region id that caused the overflow is already
1042 * leaked). So we must detect buffer overflow in advance.
1043 */
1044 snprintf(result, maxlen, "%d", INT_MAX);
1045 if (dm_message_test_buffer_overflow(result, maxlen)) {
1046 r = 1;
1047 goto ret;
1048 }
1049
1050 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1051 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1052 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1053 if (id < 0) {
1054 r = id;
1055 goto ret;
1056 }
1057
1058 snprintf(result, maxlen, "%d", id);
1059
1060 r = 1;
1061 goto ret;
1062
1063 ret_einval:
1064 r = -EINVAL;
1065 ret:
1066 kfree(histogram_boundaries);
1067 return r;
1068 }
1069
1070 static int message_stats_delete(struct mapped_device *md,
1071 unsigned argc, char **argv)
1072 {
1073 int id;
1074 char dummy;
1075
1076 if (argc != 2)
1077 return -EINVAL;
1078
1079 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1080 return -EINVAL;
1081
1082 return dm_stats_delete(dm_get_stats(md), id);
1083 }
1084
1085 static int message_stats_clear(struct mapped_device *md,
1086 unsigned argc, char **argv)
1087 {
1088 int id;
1089 char dummy;
1090
1091 if (argc != 2)
1092 return -EINVAL;
1093
1094 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1095 return -EINVAL;
1096
1097 return dm_stats_clear(dm_get_stats(md), id);
1098 }
1099
1100 static int message_stats_list(struct mapped_device *md,
1101 unsigned argc, char **argv,
1102 char *result, unsigned maxlen)
1103 {
1104 int r;
1105 const char *program = NULL;
1106
1107 if (argc < 1 || argc > 2)
1108 return -EINVAL;
1109
1110 if (argc > 1) {
1111 program = kstrdup(argv[1], GFP_KERNEL);
1112 if (!program)
1113 return -ENOMEM;
1114 }
1115
1116 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1117
1118 kfree(program);
1119
1120 return r;
1121 }
1122
1123 static int message_stats_print(struct mapped_device *md,
1124 unsigned argc, char **argv, bool clear,
1125 char *result, unsigned maxlen)
1126 {
1127 int id;
1128 char dummy;
1129 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1130
1131 if (argc != 2 && argc != 4)
1132 return -EINVAL;
1133
1134 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1135 return -EINVAL;
1136
1137 if (argc > 3) {
1138 if (strcmp(argv[2], "-") &&
1139 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1140 return -EINVAL;
1141 if (strcmp(argv[3], "-") &&
1142 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1143 return -EINVAL;
1144 }
1145
1146 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1147 result, maxlen);
1148 }
1149
1150 static int message_stats_set_aux(struct mapped_device *md,
1151 unsigned argc, char **argv)
1152 {
1153 int id;
1154 char dummy;
1155
1156 if (argc != 3)
1157 return -EINVAL;
1158
1159 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1160 return -EINVAL;
1161
1162 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1163 }
1164
1165 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1166 char *result, unsigned maxlen)
1167 {
1168 int r;
1169
1170 /* All messages here must start with '@' */
1171 if (!strcasecmp(argv[0], "@stats_create"))
1172 r = message_stats_create(md, argc, argv, result, maxlen);
1173 else if (!strcasecmp(argv[0], "@stats_delete"))
1174 r = message_stats_delete(md, argc, argv);
1175 else if (!strcasecmp(argv[0], "@stats_clear"))
1176 r = message_stats_clear(md, argc, argv);
1177 else if (!strcasecmp(argv[0], "@stats_list"))
1178 r = message_stats_list(md, argc, argv, result, maxlen);
1179 else if (!strcasecmp(argv[0], "@stats_print"))
1180 r = message_stats_print(md, argc, argv, false, result, maxlen);
1181 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1182 r = message_stats_print(md, argc, argv, true, result, maxlen);
1183 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1184 r = message_stats_set_aux(md, argc, argv);
1185 else
1186 return 2; /* this wasn't a stats message */
1187
1188 if (r == -EINVAL)
1189 DMWARN("Invalid parameters for message %s", argv[0]);
1190
1191 return r;
1192 }
1193
1194 int __init dm_statistics_init(void)
1195 {
1196 shared_memory_amount = 0;
1197 dm_stat_need_rcu_barrier = 0;
1198 return 0;
1199 }
1200
1201 void dm_statistics_exit(void)
1202 {
1203 if (dm_stat_need_rcu_barrier)
1204 rcu_barrier();
1205 if (WARN_ON(shared_memory_amount))
1206 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1207 }
1208
1209 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1210 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
Linux with added FPC-III support