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\n", s->id,
461 (unsigned long long)s->start,
462 (unsigned long long)len,
463 (unsigned long long)s->step,
468 mutex_unlock(&stats->mutex);
473 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
474 struct dm_stat_percpu *p)
477 * This is racy, but so is part_round_stats_single.
479 unsigned long long now, difference;
480 unsigned in_flight_read, in_flight_write;
482 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
485 now = ktime_to_ns(ktime_get());
487 difference = now - shared->stamp;
491 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
492 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
494 p->io_ticks[READ] += difference;
496 p->io_ticks[WRITE] += difference;
497 if (in_flight_read + in_flight_write) {
498 p->io_ticks_total += difference;
499 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
504 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
505 unsigned long bi_rw, sector_t len,
506 struct dm_stats_aux *stats_aux, bool end,
507 unsigned long duration_jiffies)
509 unsigned long idx = bi_rw & REQ_WRITE;
510 struct dm_stat_shared *shared = &s->stat_shared[entry];
511 struct dm_stat_percpu *p;
514 * For strict correctness we should use local_irq_save/restore
515 * instead of preempt_disable/enable.
517 * preempt_disable/enable is racy if the driver finishes bios
518 * from non-interrupt context as well as from interrupt context
519 * or from more different interrupts.
521 * On 64-bit architectures the race only results in not counting some
522 * events, so it is acceptable. On 32-bit architectures the race could
523 * cause the counter going off by 2^32, so we need to do proper locking
526 * part_stat_lock()/part_stat_unlock() have this race too.
528 #if BITS_PER_LONG == 32
530 local_irq_save(flags);
534 p = &s->stat_percpu[smp_processor_id()][entry];
537 dm_stat_round(s, shared, p);
538 atomic_inc(&shared->in_flight[idx]);
540 unsigned long long duration;
541 dm_stat_round(s, shared, p);
542 atomic_dec(&shared->in_flight[idx]);
543 p->sectors[idx] += len;
545 p->merges[idx] += stats_aux->merged;
546 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
547 p->ticks[idx] += duration_jiffies;
548 duration = jiffies_to_msecs(duration_jiffies);
550 p->ticks[idx] += stats_aux->duration_ns;
551 duration = stats_aux->duration_ns;
553 if (s->n_histogram_entries) {
554 unsigned lo = 0, hi = s->n_histogram_entries + 1;
555 while (lo + 1 < hi) {
556 unsigned mid = (lo + hi) / 2;
557 if (s->histogram_boundaries[mid - 1] > duration) {
568 #if BITS_PER_LONG == 32
569 local_irq_restore(flags);
575 static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw,
576 sector_t bi_sector, sector_t end_sector,
577 bool end, unsigned long duration_jiffies,
578 struct dm_stats_aux *stats_aux)
580 sector_t rel_sector, offset, todo, fragment_len;
583 if (end_sector <= s->start || bi_sector >= s->end)
585 if (unlikely(bi_sector < s->start)) {
587 todo = end_sector - s->start;
589 rel_sector = bi_sector - s->start;
590 todo = end_sector - bi_sector;
592 if (unlikely(end_sector > s->end))
593 todo -= (end_sector - s->end);
595 offset = dm_sector_div64(rel_sector, s->step);
598 if (WARN_ON_ONCE(entry >= s->n_entries)) {
599 DMCRIT("Invalid area access in region id %d", s->id);
603 if (fragment_len > s->step - offset)
604 fragment_len = s->step - offset;
605 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
606 stats_aux, end, duration_jiffies);
607 todo -= fragment_len;
610 } while (unlikely(todo != 0));
613 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
614 sector_t bi_sector, unsigned bi_sectors, bool end,
615 unsigned long duration_jiffies,
616 struct dm_stats_aux *stats_aux)
620 struct dm_stats_last_position *last;
621 bool got_precise_time;
623 if (unlikely(!bi_sectors))
626 end_sector = bi_sector + bi_sectors;
630 * A race condition can at worst result in the merged flag being
631 * misrepresented, so we don't have to disable preemption here.
633 last = raw_cpu_ptr(stats->last);
635 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
636 ((bi_rw & (REQ_WRITE | REQ_DISCARD)) ==
637 (ACCESS_ONCE(last->last_rw) & (REQ_WRITE | REQ_DISCARD)))
639 ACCESS_ONCE(last->last_sector) = end_sector;
640 ACCESS_ONCE(last->last_rw) = bi_rw;
645 got_precise_time = false;
646 list_for_each_entry_rcu(s, &stats->list, list_entry) {
647 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
649 stats_aux->duration_ns = ktime_to_ns(ktime_get());
651 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
652 got_precise_time = true;
654 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
660 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
661 struct dm_stat *s, size_t x)
664 struct dm_stat_percpu *p;
667 p = &s->stat_percpu[smp_processor_id()][x];
668 dm_stat_round(s, shared, p);
671 shared->tmp.sectors[READ] = 0;
672 shared->tmp.sectors[WRITE] = 0;
673 shared->tmp.ios[READ] = 0;
674 shared->tmp.ios[WRITE] = 0;
675 shared->tmp.merges[READ] = 0;
676 shared->tmp.merges[WRITE] = 0;
677 shared->tmp.ticks[READ] = 0;
678 shared->tmp.ticks[WRITE] = 0;
679 shared->tmp.io_ticks[READ] = 0;
680 shared->tmp.io_ticks[WRITE] = 0;
681 shared->tmp.io_ticks_total = 0;
682 shared->tmp.time_in_queue = 0;
684 if (s->n_histogram_entries)
685 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
687 for_each_possible_cpu(cpu) {
688 p = &s->stat_percpu[cpu][x];
689 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
690 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
691 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
692 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
693 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
694 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
695 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
696 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
697 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
698 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
699 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
700 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
701 if (s->n_histogram_entries) {
703 for (i = 0; i < s->n_histogram_entries + 1; i++)
704 shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]);
709 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
710 bool init_tmp_percpu_totals)
713 struct dm_stat_shared *shared;
714 struct dm_stat_percpu *p;
716 for (x = idx_start; x < idx_end; x++) {
717 shared = &s->stat_shared[x];
718 if (init_tmp_percpu_totals)
719 __dm_stat_init_temporary_percpu_totals(shared, s, x);
721 p = &s->stat_percpu[smp_processor_id()][x];
722 p->sectors[READ] -= shared->tmp.sectors[READ];
723 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
724 p->ios[READ] -= shared->tmp.ios[READ];
725 p->ios[WRITE] -= shared->tmp.ios[WRITE];
726 p->merges[READ] -= shared->tmp.merges[READ];
727 p->merges[WRITE] -= shared->tmp.merges[WRITE];
728 p->ticks[READ] -= shared->tmp.ticks[READ];
729 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
730 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
731 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
732 p->io_ticks_total -= shared->tmp.io_ticks_total;
733 p->time_in_queue -= shared->tmp.time_in_queue;
735 if (s->n_histogram_entries) {
737 for (i = 0; i < s->n_histogram_entries + 1; i++) {
739 p = &s->stat_percpu[smp_processor_id()][x];
740 p->histogram[i] -= shared->tmp.histogram[i];
747 static int dm_stats_clear(struct dm_stats *stats, int id)
751 mutex_lock(&stats->mutex);
753 s = __dm_stats_find(stats, id);
755 mutex_unlock(&stats->mutex);
759 __dm_stat_clear(s, 0, s->n_entries, true);
761 mutex_unlock(&stats->mutex);
767 * This is like jiffies_to_msec, but works for 64-bit values.
769 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
771 unsigned long long result;
774 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
779 result = jiffies_to_msecs(j & 0x3fffff);
781 mult = jiffies_to_msecs(1 << 22);
782 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
785 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
790 static int dm_stats_print(struct dm_stats *stats, int id,
791 size_t idx_start, size_t idx_len,
792 bool clear, char *result, unsigned maxlen)
797 sector_t start, end, step;
799 struct dm_stat_shared *shared;
803 * <start_sector>+<length> counters
806 mutex_lock(&stats->mutex);
808 s = __dm_stats_find(stats, id);
810 mutex_unlock(&stats->mutex);
814 idx_end = idx_start + idx_len;
815 if (idx_end < idx_start ||
816 idx_end > s->n_entries)
817 idx_end = s->n_entries;
819 if (idx_start > idx_end)
823 start = s->start + (step * idx_start);
825 for (x = idx_start; x < idx_end; x++, start = end) {
826 shared = &s->stat_shared[x];
828 if (unlikely(end > s->end))
831 __dm_stat_init_temporary_percpu_totals(shared, s, x);
833 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
834 (unsigned long long)start,
835 (unsigned long long)step,
836 shared->tmp.ios[READ],
837 shared->tmp.merges[READ],
838 shared->tmp.sectors[READ],
839 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
840 shared->tmp.ios[WRITE],
841 shared->tmp.merges[WRITE],
842 shared->tmp.sectors[WRITE],
843 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
844 dm_stat_in_flight(shared),
845 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
846 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
847 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
848 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
849 if (s->n_histogram_entries) {
851 for (i = 0; i < s->n_histogram_entries + 1; i++) {
852 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
857 if (unlikely(sz + 1 >= maxlen))
858 goto buffer_overflow;
862 __dm_stat_clear(s, idx_start, idx_end, false);
865 mutex_unlock(&stats->mutex);
870 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
873 const char *new_aux_data;
875 mutex_lock(&stats->mutex);
877 s = __dm_stats_find(stats, id);
879 mutex_unlock(&stats->mutex);
883 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
885 mutex_unlock(&stats->mutex);
890 s->aux_data = new_aux_data;
892 mutex_unlock(&stats->mutex);
897 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
898 unsigned long long **histogram_boundaries)
902 unsigned long long last;
904 *n_histogram_entries = 1;
907 (*n_histogram_entries)++;
909 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
910 if (!*histogram_boundaries)
916 unsigned long long hi;
919 s = sscanf(h, "%llu%c", &hi, &ch);
920 if (!s || (s == 2 && ch != ','))
925 (*histogram_boundaries)[n] = hi;
928 h = strchr(h, ',') + 1;
933 static int message_stats_create(struct mapped_device *md,
934 unsigned argc, char **argv,
935 char *result, unsigned maxlen)
940 unsigned long long start, end, len, step;
942 const char *program_id, *aux_data;
943 unsigned stat_flags = 0;
945 unsigned n_histogram_entries = 0;
946 unsigned long long *histogram_boundaries = NULL;
948 struct dm_arg_set as, as_backup;
950 unsigned feature_args;
954 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
962 dm_consume_args(&as, 1);
964 a = dm_shift_arg(&as);
965 if (!strcmp(a, "-")) {
967 len = dm_get_size(md);
970 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
971 start != (sector_t)start || len != (sector_t)len)
978 a = dm_shift_arg(&as);
979 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
983 if (do_div(step, divisor))
987 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
988 step != (sector_t)step || !step)
992 a = dm_shift_arg(&as);
993 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
994 while (feature_args--) {
995 a = dm_shift_arg(&as);
998 if (!strcasecmp(a, "precise_timestamps"))
999 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1000 else if (!strncasecmp(a, "histogram:", 10)) {
1001 if (n_histogram_entries)
1003 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1015 a = dm_shift_arg(&as);
1019 a = dm_shift_arg(&as);
1027 * If a buffer overflow happens after we created the region,
1028 * it's too late (the userspace would retry with a larger
1029 * buffer, but the region id that caused the overflow is already
1030 * leaked). So we must detect buffer overflow in advance.
1032 snprintf(result, maxlen, "%d", INT_MAX);
1033 if (dm_message_test_buffer_overflow(result, maxlen)) {
1038 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1039 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1040 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1046 snprintf(result, maxlen, "%d", id);
1054 kfree(histogram_boundaries);
1058 static int message_stats_delete(struct mapped_device *md,
1059 unsigned argc, char **argv)
1067 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1070 return dm_stats_delete(dm_get_stats(md), id);
1073 static int message_stats_clear(struct mapped_device *md,
1074 unsigned argc, char **argv)
1082 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1085 return dm_stats_clear(dm_get_stats(md), id);
1088 static int message_stats_list(struct mapped_device *md,
1089 unsigned argc, char **argv,
1090 char *result, unsigned maxlen)
1093 const char *program = NULL;
1095 if (argc < 1 || argc > 2)
1099 program = kstrdup(argv[1], GFP_KERNEL);
1104 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1111 static int message_stats_print(struct mapped_device *md,
1112 unsigned argc, char **argv, bool clear,
1113 char *result, unsigned maxlen)
1117 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1119 if (argc != 2 && argc != 4)
1122 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1126 if (strcmp(argv[2], "-") &&
1127 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1129 if (strcmp(argv[3], "-") &&
1130 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1134 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1138 static int message_stats_set_aux(struct mapped_device *md,
1139 unsigned argc, char **argv)
1147 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1150 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1153 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1154 char *result, unsigned maxlen)
1158 /* All messages here must start with '@' */
1159 if (!strcasecmp(argv[0], "@stats_create"))
1160 r = message_stats_create(md, argc, argv, result, maxlen);
1161 else if (!strcasecmp(argv[0], "@stats_delete"))
1162 r = message_stats_delete(md, argc, argv);
1163 else if (!strcasecmp(argv[0], "@stats_clear"))
1164 r = message_stats_clear(md, argc, argv);
1165 else if (!strcasecmp(argv[0], "@stats_list"))
1166 r = message_stats_list(md, argc, argv, result, maxlen);
1167 else if (!strcasecmp(argv[0], "@stats_print"))
1168 r = message_stats_print(md, argc, argv, false, result, maxlen);
1169 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1170 r = message_stats_print(md, argc, argv, true, result, maxlen);
1171 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1172 r = message_stats_set_aux(md, argc, argv);
1174 return 2; /* this wasn't a stats message */
1177 DMWARN("Invalid parameters for message %s", argv[0]);
1182 int __init dm_statistics_init(void)
1184 shared_memory_amount = 0;
1185 dm_stat_need_rcu_barrier = 0;
1189 void dm_statistics_exit(void)
1191 if (dm_stat_need_rcu_barrier)
1193 if (WARN_ON(shared_memory_amount))
1194 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1197 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1198 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");