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>
10 #include <linux/module.h>
11 #include <linux/device-mapper.h>
16 #define DM_MSG_PREFIX "stats"
18 static int dm_stat_need_rcu_barrier;
21 * Using 64-bit values to avoid overflow (which is a
22 * problem that block/genhd.c's IO accounting has).
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;
35 struct dm_stat_shared {
36 atomic_t in_flight[2];
37 unsigned long long stamp;
38 struct dm_stat_percpu tmp;
42 struct list_head list_entry;
49 unsigned n_histogram_entries;
50 unsigned long long *histogram_boundaries;
51 const char *program_id;
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];
61 #define STAT_PRECISE_TIMESTAMPS 1
63 struct dm_stats_last_position {
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.
73 #define DM_STATS_MEMORY_FACTOR 4
74 #define DM_STATS_VMALLOC_FACTOR 2
76 static DEFINE_SPINLOCK(shared_memory_lock);
78 static unsigned long shared_memory_amount;
80 static bool __check_shared_memory(size_t alloc_size)
84 a = shared_memory_amount + alloc_size;
85 if (a < shared_memory_amount)
87 if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR)
90 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
96 static bool check_shared_memory(size_t alloc_size)
100 spin_lock_irq(&shared_memory_lock);
102 ret = __check_shared_memory(alloc_size);
104 spin_unlock_irq(&shared_memory_lock);
109 static bool claim_shared_memory(size_t alloc_size)
111 spin_lock_irq(&shared_memory_lock);
113 if (!__check_shared_memory(alloc_size)) {
114 spin_unlock_irq(&shared_memory_lock);
118 shared_memory_amount += alloc_size;
120 spin_unlock_irq(&shared_memory_lock);
125 static void free_shared_memory(size_t alloc_size)
129 spin_lock_irqsave(&shared_memory_lock, flags);
131 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
132 spin_unlock_irqrestore(&shared_memory_lock, flags);
133 DMCRIT("Memory usage accounting bug.");
137 shared_memory_amount -= alloc_size;
139 spin_unlock_irqrestore(&shared_memory_lock, flags);
142 static void *dm_kvzalloc(size_t alloc_size, int node)
146 if (!claim_shared_memory(alloc_size))
149 if (alloc_size <= KMALLOC_MAX_SIZE) {
150 p = kzalloc_node(alloc_size, GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN, node);
154 p = vzalloc_node(alloc_size, node);
158 free_shared_memory(alloc_size);
163 static void dm_kvfree(void *ptr, size_t alloc_size)
168 free_shared_memory(alloc_size);
173 static void dm_stat_free(struct rcu_head *head)
176 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
178 kfree(s->program_id);
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);
184 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
185 dm_kvfree(s, s->shared_alloc_size);
188 static int dm_stat_in_flight(struct dm_stat_shared *shared)
190 return atomic_read(&shared->in_flight[READ]) +
191 atomic_read(&shared->in_flight[WRITE]);
194 void dm_stats_init(struct dm_stats *stats)
197 struct dm_stats_last_position *last;
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;
209 void dm_stats_cleanup(struct dm_stats *stats)
213 struct dm_stat_shared *shared;
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",
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]));
231 dm_stat_free(&s->rcu_head);
233 free_percpu(stats->last);
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)
246 struct dm_stat *s, *tmp_s;
249 size_t shared_alloc_size;
250 size_t percpu_alloc_size;
251 size_t histogram_alloc_size;
252 struct dm_stat_percpu *p;
257 if (end < start || !step)
260 n_entries = end - start;
261 if (dm_sector_div64(n_entries, step))
264 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
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)
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)
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))
279 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
280 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
283 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
287 s->stat_flags = stat_flags;
288 s->n_entries = n_entries;
292 s->shared_alloc_size = shared_alloc_size;
293 s->percpu_alloc_size = percpu_alloc_size;
294 s->histogram_alloc_size = histogram_alloc_size;
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) {
304 s->program_id = kstrdup(program_id, GFP_KERNEL);
305 if (!s->program_id) {
309 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
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);
320 if (s->n_histogram_entries) {
321 unsigned long long *hi;
322 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
327 for (ni = 0; ni < n_entries; ni++) {
328 s->stat_shared[ni].tmp.histogram = hi;
329 hi += s->n_histogram_entries + 1;
333 for_each_possible_cpu(cpu) {
334 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
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));
347 for (ni = 0; ni < n_entries; ni++) {
348 p[ni].histogram = hi;
349 hi += s->n_histogram_entries + 1;
355 * Suspend/resume to make sure there is no i/o in flight,
356 * so that newly created statistics will be exact.
358 * (note: we couldn't suspend earlier because we must not
359 * allocate memory while suspended)
361 suspend_callback(md);
363 mutex_lock(&stats->mutex);
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)) {
369 goto out_unlock_resume;
371 if (tmp_s->id > s->id)
373 if (unlikely(s->id == INT_MAX)) {
375 goto out_unlock_resume;
380 list_add_tail_rcu(&s->list_entry, l);
381 mutex_unlock(&stats->mutex);
388 mutex_unlock(&stats->mutex);
391 dm_stat_free(&s->rcu_head);
395 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
399 list_for_each_entry(s, &stats->list, list_entry) {
409 static int dm_stats_delete(struct dm_stats *stats, int id)
414 mutex_lock(&stats->mutex);
416 s = __dm_stats_find(stats, id);
418 mutex_unlock(&stats->mutex);
422 list_del_rcu(&s->list_entry);
423 mutex_unlock(&stats->mutex);
426 * vfree can't be called from RCU callback
428 for_each_possible_cpu(cpu)
429 if (is_vmalloc_addr(s->stat_percpu) ||
430 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
432 if (is_vmalloc_addr(s) ||
433 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
435 synchronize_rcu_expedited();
436 dm_stat_free(&s->rcu_head);
438 ACCESS_ONCE(dm_stat_need_rcu_barrier) = 1;
439 call_rcu(&s->rcu_head, dm_stat_free);
444 static int dm_stats_list(struct dm_stats *stats, const char *program,
445 char *result, unsigned maxlen)
453 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
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,
466 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
467 DMEMIT(" precise_timestamps");
468 if (s->n_histogram_entries) {
470 DMEMIT(" histogram:");
471 for (i = 0; i < s->n_histogram_entries; i++) {
474 DMEMIT("%llu", s->histogram_boundaries[i]);
480 mutex_unlock(&stats->mutex);
485 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
486 struct dm_stat_percpu *p)
489 * This is racy, but so is part_round_stats_single.
491 unsigned long long now, difference;
492 unsigned in_flight_read, in_flight_write;
494 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
497 now = ktime_to_ns(ktime_get());
499 difference = now - shared->stamp;
503 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
504 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
506 p->io_ticks[READ] += difference;
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;
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)
521 unsigned long idx = bi_rw & REQ_WRITE;
522 struct dm_stat_shared *shared = &s->stat_shared[entry];
523 struct dm_stat_percpu *p;
526 * For strict correctness we should use local_irq_save/restore
527 * instead of preempt_disable/enable.
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.
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
538 * part_stat_lock()/part_stat_unlock() have this race too.
540 #if BITS_PER_LONG == 32
542 local_irq_save(flags);
546 p = &s->stat_percpu[smp_processor_id()][entry];
549 dm_stat_round(s, shared, p);
550 atomic_inc(&shared->in_flight[idx]);
552 unsigned long long duration;
553 dm_stat_round(s, shared, p);
554 atomic_dec(&shared->in_flight[idx]);
555 p->sectors[idx] += len;
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);
562 p->ticks[idx] += stats_aux->duration_ns;
563 duration = stats_aux->duration_ns;
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) {
580 #if BITS_PER_LONG == 32
581 local_irq_restore(flags);
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)
592 sector_t rel_sector, offset, todo, fragment_len;
595 if (end_sector <= s->start || bi_sector >= s->end)
597 if (unlikely(bi_sector < s->start)) {
599 todo = end_sector - s->start;
601 rel_sector = bi_sector - s->start;
602 todo = end_sector - bi_sector;
604 if (unlikely(end_sector > s->end))
605 todo -= (end_sector - s->end);
607 offset = dm_sector_div64(rel_sector, s->step);
610 if (WARN_ON_ONCE(entry >= s->n_entries)) {
611 DMCRIT("Invalid area access in region id %d", s->id);
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;
622 } while (unlikely(todo != 0));
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)
632 struct dm_stats_last_position *last;
633 bool got_precise_time;
635 if (unlikely(!bi_sectors))
638 end_sector = bi_sector + bi_sectors;
642 * A race condition can at worst result in the merged flag being
643 * misrepresented, so we don't have to disable preemption here.
645 last = raw_cpu_ptr(stats->last);
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)))
651 ACCESS_ONCE(last->last_sector) = end_sector;
652 ACCESS_ONCE(last->last_rw) = bi_rw;
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) {
661 stats_aux->duration_ns = ktime_to_ns(ktime_get());
663 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
664 got_precise_time = true;
666 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
672 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
673 struct dm_stat *s, size_t x)
676 struct dm_stat_percpu *p;
679 p = &s->stat_percpu[smp_processor_id()][x];
680 dm_stat_round(s, shared, p);
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;
696 if (s->n_histogram_entries)
697 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
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) {
715 for (i = 0; i < s->n_histogram_entries + 1; i++)
716 shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]);
721 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
722 bool init_tmp_percpu_totals)
725 struct dm_stat_shared *shared;
726 struct dm_stat_percpu *p;
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);
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;
747 if (s->n_histogram_entries) {
749 for (i = 0; i < s->n_histogram_entries + 1; i++) {
751 p = &s->stat_percpu[smp_processor_id()][x];
752 p->histogram[i] -= shared->tmp.histogram[i];
759 static int dm_stats_clear(struct dm_stats *stats, int id)
763 mutex_lock(&stats->mutex);
765 s = __dm_stats_find(stats, id);
767 mutex_unlock(&stats->mutex);
771 __dm_stat_clear(s, 0, s->n_entries, true);
773 mutex_unlock(&stats->mutex);
779 * This is like jiffies_to_msec, but works for 64-bit values.
781 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
783 unsigned long long result;
786 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
791 result = jiffies_to_msecs(j & 0x3fffff);
793 mult = jiffies_to_msecs(1 << 22);
794 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
797 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
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)
809 sector_t start, end, step;
811 struct dm_stat_shared *shared;
815 * <start_sector>+<length> counters
818 mutex_lock(&stats->mutex);
820 s = __dm_stats_find(stats, id);
822 mutex_unlock(&stats->mutex);
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;
831 if (idx_start > idx_end)
835 start = s->start + (step * idx_start);
837 for (x = idx_start; x < idx_end; x++, start = end) {
838 shared = &s->stat_shared[x];
840 if (unlikely(end > s->end))
843 __dm_stat_init_temporary_percpu_totals(shared, s, x);
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) {
863 for (i = 0; i < s->n_histogram_entries + 1; i++) {
864 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
869 if (unlikely(sz + 1 >= maxlen))
870 goto buffer_overflow;
874 __dm_stat_clear(s, idx_start, idx_end, false);
877 mutex_unlock(&stats->mutex);
882 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
885 const char *new_aux_data;
887 mutex_lock(&stats->mutex);
889 s = __dm_stats_find(stats, id);
891 mutex_unlock(&stats->mutex);
895 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
897 mutex_unlock(&stats->mutex);
902 s->aux_data = new_aux_data;
904 mutex_unlock(&stats->mutex);
909 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
910 unsigned long long **histogram_boundaries)
914 unsigned long long last;
916 *n_histogram_entries = 1;
919 (*n_histogram_entries)++;
921 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
922 if (!*histogram_boundaries)
928 unsigned long long hi;
931 s = sscanf(h, "%llu%c", &hi, &ch);
932 if (!s || (s == 2 && ch != ','))
937 (*histogram_boundaries)[n] = hi;
940 h = strchr(h, ',') + 1;
945 static int message_stats_create(struct mapped_device *md,
946 unsigned argc, char **argv,
947 char *result, unsigned maxlen)
952 unsigned long long start, end, len, step;
954 const char *program_id, *aux_data;
955 unsigned stat_flags = 0;
957 unsigned n_histogram_entries = 0;
958 unsigned long long *histogram_boundaries = NULL;
960 struct dm_arg_set as, as_backup;
962 unsigned feature_args;
966 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
974 dm_consume_args(&as, 1);
976 a = dm_shift_arg(&as);
977 if (!strcmp(a, "-")) {
979 len = dm_get_size(md);
982 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
983 start != (sector_t)start || len != (sector_t)len)
990 a = dm_shift_arg(&as);
991 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
995 if (do_div(step, divisor))
999 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1000 step != (sector_t)step || !step)
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);
1010 if (!strcasecmp(a, "precise_timestamps"))
1011 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1012 else if (!strncasecmp(a, "histogram:", 10)) {
1013 if (n_histogram_entries)
1015 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1027 a = dm_shift_arg(&as);
1031 a = dm_shift_arg(&as);
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.
1044 snprintf(result, maxlen, "%d", INT_MAX);
1045 if (dm_message_test_buffer_overflow(result, maxlen)) {
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);
1058 snprintf(result, maxlen, "%d", id);
1066 kfree(histogram_boundaries);
1070 static int message_stats_delete(struct mapped_device *md,
1071 unsigned argc, char **argv)
1079 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1082 return dm_stats_delete(dm_get_stats(md), id);
1085 static int message_stats_clear(struct mapped_device *md,
1086 unsigned argc, char **argv)
1094 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1097 return dm_stats_clear(dm_get_stats(md), id);
1100 static int message_stats_list(struct mapped_device *md,
1101 unsigned argc, char **argv,
1102 char *result, unsigned maxlen)
1105 const char *program = NULL;
1107 if (argc < 1 || argc > 2)
1111 program = kstrdup(argv[1], GFP_KERNEL);
1116 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1123 static int message_stats_print(struct mapped_device *md,
1124 unsigned argc, char **argv, bool clear,
1125 char *result, unsigned maxlen)
1129 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1131 if (argc != 2 && argc != 4)
1134 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1138 if (strcmp(argv[2], "-") &&
1139 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1141 if (strcmp(argv[3], "-") &&
1142 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1146 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1150 static int message_stats_set_aux(struct mapped_device *md,
1151 unsigned argc, char **argv)
1159 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1162 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1165 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1166 char *result, unsigned maxlen)
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);
1186 return 2; /* this wasn't a stats message */
1189 DMWARN("Invalid parameters for message %s", argv[0]);
1194 int __init dm_statistics_init(void)
1196 shared_memory_amount = 0;
1197 dm_stat_need_rcu_barrier = 0;
1201 void dm_statistics_exit(void)
1203 if (dm_stat_need_rcu_barrier)
1205 if (WARN_ON(shared_memory_amount))
1206 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
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");