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>
11 #include <linux/module.h>
12 #include <linux/device-mapper.h>
17 #define DM_MSG_PREFIX "stats"
19 static int dm_stat_need_rcu_barrier;
22 * Using 64-bit values to avoid overflow (which is a
23 * problem that block/genhd.c's IO accounting has).
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;
36 struct dm_stat_shared {
37 atomic_t in_flight[2];
38 unsigned long long stamp;
39 struct dm_stat_percpu tmp;
43 struct list_head list_entry;
50 unsigned n_histogram_entries;
51 unsigned long long *histogram_boundaries;
52 const char *program_id;
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[];
62 #define STAT_PRECISE_TIMESTAMPS 1
64 struct dm_stats_last_position {
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.
74 #define DM_STATS_MEMORY_FACTOR 4
75 #define DM_STATS_VMALLOC_FACTOR 2
77 static DEFINE_SPINLOCK(shared_memory_lock);
79 static unsigned long shared_memory_amount;
81 static bool __check_shared_memory(size_t alloc_size)
85 a = shared_memory_amount + alloc_size;
86 if (a < shared_memory_amount)
88 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
91 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
97 static bool check_shared_memory(size_t alloc_size)
101 spin_lock_irq(&shared_memory_lock);
103 ret = __check_shared_memory(alloc_size);
105 spin_unlock_irq(&shared_memory_lock);
110 static bool claim_shared_memory(size_t alloc_size)
112 spin_lock_irq(&shared_memory_lock);
114 if (!__check_shared_memory(alloc_size)) {
115 spin_unlock_irq(&shared_memory_lock);
119 shared_memory_amount += alloc_size;
121 spin_unlock_irq(&shared_memory_lock);
126 static void free_shared_memory(size_t alloc_size)
130 spin_lock_irqsave(&shared_memory_lock, flags);
132 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
133 spin_unlock_irqrestore(&shared_memory_lock, flags);
134 DMCRIT("Memory usage accounting bug.");
138 shared_memory_amount -= alloc_size;
140 spin_unlock_irqrestore(&shared_memory_lock, flags);
143 static void *dm_kvzalloc(size_t alloc_size, int node)
147 if (!claim_shared_memory(alloc_size))
150 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
154 free_shared_memory(alloc_size);
159 static void dm_kvfree(void *ptr, size_t alloc_size)
164 free_shared_memory(alloc_size);
169 static void dm_stat_free(struct rcu_head *head)
172 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
174 kfree(s->histogram_boundaries);
175 kfree(s->program_id);
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);
181 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
182 dm_kvfree(s, s->shared_alloc_size);
185 static int dm_stat_in_flight(struct dm_stat_shared *shared)
187 return atomic_read(&shared->in_flight[READ]) +
188 atomic_read(&shared->in_flight[WRITE]);
191 void dm_stats_init(struct dm_stats *stats)
194 struct dm_stats_last_position *last;
196 mutex_init(&stats->mutex);
197 INIT_LIST_HEAD(&stats->list);
198 stats->precise_timestamps = false;
199 stats->last = alloc_percpu(struct dm_stats_last_position);
200 for_each_possible_cpu(cpu) {
201 last = per_cpu_ptr(stats->last, cpu);
202 last->last_sector = (sector_t)ULLONG_MAX;
203 last->last_rw = UINT_MAX;
207 void dm_stats_cleanup(struct dm_stats *stats)
211 struct dm_stat_shared *shared;
213 while (!list_empty(&stats->list)) {
214 s = container_of(stats->list.next, struct dm_stat, list_entry);
215 list_del(&s->list_entry);
216 for (ni = 0; ni < s->n_entries; ni++) {
217 shared = &s->stat_shared[ni];
218 if (WARN_ON(dm_stat_in_flight(shared))) {
219 DMCRIT("leaked in-flight counter at index %lu "
220 "(start %llu, end %llu, step %llu): reads %d, writes %d",
222 (unsigned long long)s->start,
223 (unsigned long long)s->end,
224 (unsigned long long)s->step,
225 atomic_read(&shared->in_flight[READ]),
226 atomic_read(&shared->in_flight[WRITE]));
230 dm_stat_free(&s->rcu_head);
232 free_percpu(stats->last);
233 mutex_destroy(&stats->mutex);
236 static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
239 struct dm_stat *tmp_s;
240 bool precise_timestamps = false;
242 list_for_each(l, &stats->list) {
243 tmp_s = container_of(l, struct dm_stat, list_entry);
244 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
245 precise_timestamps = true;
249 stats->precise_timestamps = precise_timestamps;
252 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
253 sector_t step, unsigned stat_flags,
254 unsigned n_histogram_entries,
255 unsigned long long *histogram_boundaries,
256 const char *program_id, const char *aux_data,
257 void (*suspend_callback)(struct mapped_device *),
258 void (*resume_callback)(struct mapped_device *),
259 struct mapped_device *md)
262 struct dm_stat *s, *tmp_s;
265 size_t shared_alloc_size;
266 size_t percpu_alloc_size;
267 size_t histogram_alloc_size;
268 struct dm_stat_percpu *p;
273 if (end < start || !step)
276 n_entries = end - start;
277 if (dm_sector_div64(n_entries, step))
280 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
283 shared_alloc_size = struct_size(s, stat_shared, n_entries);
284 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
287 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
288 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
291 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
292 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
295 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
296 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
299 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
303 s->stat_flags = stat_flags;
304 s->n_entries = n_entries;
308 s->shared_alloc_size = shared_alloc_size;
309 s->percpu_alloc_size = percpu_alloc_size;
310 s->histogram_alloc_size = histogram_alloc_size;
312 s->n_histogram_entries = n_histogram_entries;
313 s->histogram_boundaries = kmemdup(histogram_boundaries,
314 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
315 if (!s->histogram_boundaries) {
320 s->program_id = kstrdup(program_id, GFP_KERNEL);
321 if (!s->program_id) {
325 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
331 for (ni = 0; ni < n_entries; ni++) {
332 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
333 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
337 if (s->n_histogram_entries) {
338 unsigned long long *hi;
339 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
344 for (ni = 0; ni < n_entries; ni++) {
345 s->stat_shared[ni].tmp.histogram = hi;
346 hi += s->n_histogram_entries + 1;
351 for_each_possible_cpu(cpu) {
352 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
357 s->stat_percpu[cpu] = p;
358 if (s->n_histogram_entries) {
359 unsigned long long *hi;
360 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
365 for (ni = 0; ni < n_entries; ni++) {
366 p[ni].histogram = hi;
367 hi += s->n_histogram_entries + 1;
374 * Suspend/resume to make sure there is no i/o in flight,
375 * so that newly created statistics will be exact.
377 * (note: we couldn't suspend earlier because we must not
378 * allocate memory while suspended)
380 suspend_callback(md);
382 mutex_lock(&stats->mutex);
384 list_for_each(l, &stats->list) {
385 tmp_s = container_of(l, struct dm_stat, list_entry);
386 if (WARN_ON(tmp_s->id < s->id)) {
388 goto out_unlock_resume;
390 if (tmp_s->id > s->id)
392 if (unlikely(s->id == INT_MAX)) {
394 goto out_unlock_resume;
399 list_add_tail_rcu(&s->list_entry, l);
401 dm_stats_recalc_precise_timestamps(stats);
403 mutex_unlock(&stats->mutex);
410 mutex_unlock(&stats->mutex);
413 dm_stat_free(&s->rcu_head);
417 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
421 list_for_each_entry(s, &stats->list, list_entry) {
431 static int dm_stats_delete(struct dm_stats *stats, int id)
436 mutex_lock(&stats->mutex);
438 s = __dm_stats_find(stats, id);
440 mutex_unlock(&stats->mutex);
444 list_del_rcu(&s->list_entry);
446 dm_stats_recalc_precise_timestamps(stats);
448 mutex_unlock(&stats->mutex);
451 * vfree can't be called from RCU callback
453 for_each_possible_cpu(cpu)
454 if (is_vmalloc_addr(s->stat_percpu) ||
455 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
457 if (is_vmalloc_addr(s) ||
458 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
460 synchronize_rcu_expedited();
461 dm_stat_free(&s->rcu_head);
463 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
464 call_rcu(&s->rcu_head, dm_stat_free);
469 static int dm_stats_list(struct dm_stats *stats, const char *program,
470 char *result, unsigned maxlen)
478 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
481 mutex_lock(&stats->mutex);
482 list_for_each_entry(s, &stats->list, list_entry) {
483 if (!program || !strcmp(program, s->program_id)) {
484 len = s->end - s->start;
485 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
486 (unsigned long long)s->start,
487 (unsigned long long)len,
488 (unsigned long long)s->step,
491 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
492 DMEMIT(" precise_timestamps");
493 if (s->n_histogram_entries) {
495 DMEMIT(" histogram:");
496 for (i = 0; i < s->n_histogram_entries; i++) {
499 DMEMIT("%llu", s->histogram_boundaries[i]);
506 mutex_unlock(&stats->mutex);
511 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
512 struct dm_stat_percpu *p)
515 * This is racy, but so is part_round_stats_single.
517 unsigned long long now, difference;
518 unsigned in_flight_read, in_flight_write;
520 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
523 now = ktime_to_ns(ktime_get());
525 difference = now - shared->stamp;
529 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
530 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
532 p->io_ticks[READ] += difference;
534 p->io_ticks[WRITE] += difference;
535 if (in_flight_read + in_flight_write) {
536 p->io_ticks_total += difference;
537 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
542 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
543 int idx, sector_t len,
544 struct dm_stats_aux *stats_aux, bool end,
545 unsigned long duration_jiffies)
547 struct dm_stat_shared *shared = &s->stat_shared[entry];
548 struct dm_stat_percpu *p;
551 * For strict correctness we should use local_irq_save/restore
552 * instead of preempt_disable/enable.
554 * preempt_disable/enable is racy if the driver finishes bios
555 * from non-interrupt context as well as from interrupt context
556 * or from more different interrupts.
558 * On 64-bit architectures the race only results in not counting some
559 * events, so it is acceptable. On 32-bit architectures the race could
560 * cause the counter going off by 2^32, so we need to do proper locking
563 * part_stat_lock()/part_stat_unlock() have this race too.
565 #if BITS_PER_LONG == 32
567 local_irq_save(flags);
571 p = &s->stat_percpu[smp_processor_id()][entry];
574 dm_stat_round(s, shared, p);
575 atomic_inc(&shared->in_flight[idx]);
577 unsigned long long duration;
578 dm_stat_round(s, shared, p);
579 atomic_dec(&shared->in_flight[idx]);
580 p->sectors[idx] += len;
582 p->merges[idx] += stats_aux->merged;
583 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
584 p->ticks[idx] += duration_jiffies;
585 duration = jiffies_to_msecs(duration_jiffies);
587 p->ticks[idx] += stats_aux->duration_ns;
588 duration = stats_aux->duration_ns;
590 if (s->n_histogram_entries) {
591 unsigned lo = 0, hi = s->n_histogram_entries + 1;
592 while (lo + 1 < hi) {
593 unsigned mid = (lo + hi) / 2;
594 if (s->histogram_boundaries[mid - 1] > duration) {
605 #if BITS_PER_LONG == 32
606 local_irq_restore(flags);
612 static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
613 sector_t bi_sector, sector_t end_sector,
614 bool end, unsigned long duration_jiffies,
615 struct dm_stats_aux *stats_aux)
617 sector_t rel_sector, offset, todo, fragment_len;
620 if (end_sector <= s->start || bi_sector >= s->end)
622 if (unlikely(bi_sector < s->start)) {
624 todo = end_sector - s->start;
626 rel_sector = bi_sector - s->start;
627 todo = end_sector - bi_sector;
629 if (unlikely(end_sector > s->end))
630 todo -= (end_sector - s->end);
632 offset = dm_sector_div64(rel_sector, s->step);
635 if (WARN_ON_ONCE(entry >= s->n_entries)) {
636 DMCRIT("Invalid area access in region id %d", s->id);
640 if (fragment_len > s->step - offset)
641 fragment_len = s->step - offset;
642 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
643 stats_aux, end, duration_jiffies);
644 todo -= fragment_len;
647 } while (unlikely(todo != 0));
650 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
651 sector_t bi_sector, unsigned bi_sectors, bool end,
652 unsigned long start_time,
653 struct dm_stats_aux *stats_aux)
657 struct dm_stats_last_position *last;
658 bool got_precise_time;
659 unsigned long duration_jiffies = 0;
661 if (unlikely(!bi_sectors))
664 end_sector = bi_sector + bi_sectors;
668 * A race condition can at worst result in the merged flag being
669 * misrepresented, so we don't have to disable preemption here.
671 last = raw_cpu_ptr(stats->last);
673 (bi_sector == (READ_ONCE(last->last_sector) &&
675 (READ_ONCE(last->last_rw) == WRITE))
677 WRITE_ONCE(last->last_sector, end_sector);
678 WRITE_ONCE(last->last_rw, bi_rw);
680 duration_jiffies = jiffies - start_time;
684 got_precise_time = false;
685 list_for_each_entry_rcu(s, &stats->list, list_entry) {
686 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
687 /* start (!end) duration_ns is set by DM core's alloc_io() */
689 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
690 got_precise_time = true;
692 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
698 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
699 struct dm_stat *s, size_t x)
702 struct dm_stat_percpu *p;
705 p = &s->stat_percpu[smp_processor_id()][x];
706 dm_stat_round(s, shared, p);
709 shared->tmp.sectors[READ] = 0;
710 shared->tmp.sectors[WRITE] = 0;
711 shared->tmp.ios[READ] = 0;
712 shared->tmp.ios[WRITE] = 0;
713 shared->tmp.merges[READ] = 0;
714 shared->tmp.merges[WRITE] = 0;
715 shared->tmp.ticks[READ] = 0;
716 shared->tmp.ticks[WRITE] = 0;
717 shared->tmp.io_ticks[READ] = 0;
718 shared->tmp.io_ticks[WRITE] = 0;
719 shared->tmp.io_ticks_total = 0;
720 shared->tmp.time_in_queue = 0;
722 if (s->n_histogram_entries)
723 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
725 for_each_possible_cpu(cpu) {
726 p = &s->stat_percpu[cpu][x];
727 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
728 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
729 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
730 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
731 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
732 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
733 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
734 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
735 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
736 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
737 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
738 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
739 if (s->n_histogram_entries) {
741 for (i = 0; i < s->n_histogram_entries + 1; i++)
742 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
747 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
748 bool init_tmp_percpu_totals)
751 struct dm_stat_shared *shared;
752 struct dm_stat_percpu *p;
754 for (x = idx_start; x < idx_end; x++) {
755 shared = &s->stat_shared[x];
756 if (init_tmp_percpu_totals)
757 __dm_stat_init_temporary_percpu_totals(shared, s, x);
759 p = &s->stat_percpu[smp_processor_id()][x];
760 p->sectors[READ] -= shared->tmp.sectors[READ];
761 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
762 p->ios[READ] -= shared->tmp.ios[READ];
763 p->ios[WRITE] -= shared->tmp.ios[WRITE];
764 p->merges[READ] -= shared->tmp.merges[READ];
765 p->merges[WRITE] -= shared->tmp.merges[WRITE];
766 p->ticks[READ] -= shared->tmp.ticks[READ];
767 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
768 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
769 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
770 p->io_ticks_total -= shared->tmp.io_ticks_total;
771 p->time_in_queue -= shared->tmp.time_in_queue;
773 if (s->n_histogram_entries) {
775 for (i = 0; i < s->n_histogram_entries + 1; i++) {
777 p = &s->stat_percpu[smp_processor_id()][x];
778 p->histogram[i] -= shared->tmp.histogram[i];
786 static int dm_stats_clear(struct dm_stats *stats, int id)
790 mutex_lock(&stats->mutex);
792 s = __dm_stats_find(stats, id);
794 mutex_unlock(&stats->mutex);
798 __dm_stat_clear(s, 0, s->n_entries, true);
800 mutex_unlock(&stats->mutex);
806 * This is like jiffies_to_msec, but works for 64-bit values.
808 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
810 unsigned long long result;
813 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
818 result = jiffies_to_msecs(j & 0x3fffff);
820 mult = jiffies_to_msecs(1 << 22);
821 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
824 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
829 static int dm_stats_print(struct dm_stats *stats, int id,
830 size_t idx_start, size_t idx_len,
831 bool clear, char *result, unsigned maxlen)
836 sector_t start, end, step;
838 struct dm_stat_shared *shared;
842 * <start_sector>+<length> counters
845 mutex_lock(&stats->mutex);
847 s = __dm_stats_find(stats, id);
849 mutex_unlock(&stats->mutex);
853 idx_end = idx_start + idx_len;
854 if (idx_end < idx_start ||
855 idx_end > s->n_entries)
856 idx_end = s->n_entries;
858 if (idx_start > idx_end)
862 start = s->start + (step * idx_start);
864 for (x = idx_start; x < idx_end; x++, start = end) {
865 shared = &s->stat_shared[x];
867 if (unlikely(end > s->end))
870 __dm_stat_init_temporary_percpu_totals(shared, s, x);
872 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
873 (unsigned long long)start,
874 (unsigned long long)step,
875 shared->tmp.ios[READ],
876 shared->tmp.merges[READ],
877 shared->tmp.sectors[READ],
878 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
879 shared->tmp.ios[WRITE],
880 shared->tmp.merges[WRITE],
881 shared->tmp.sectors[WRITE],
882 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
883 dm_stat_in_flight(shared),
884 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
885 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
886 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
887 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
888 if (s->n_histogram_entries) {
890 for (i = 0; i < s->n_histogram_entries + 1; i++) {
891 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
896 if (unlikely(sz + 1 >= maxlen))
897 goto buffer_overflow;
903 __dm_stat_clear(s, idx_start, idx_end, false);
906 mutex_unlock(&stats->mutex);
911 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
914 const char *new_aux_data;
916 mutex_lock(&stats->mutex);
918 s = __dm_stats_find(stats, id);
920 mutex_unlock(&stats->mutex);
924 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
926 mutex_unlock(&stats->mutex);
931 s->aux_data = new_aux_data;
933 mutex_unlock(&stats->mutex);
938 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
939 unsigned long long **histogram_boundaries)
943 unsigned long long last;
945 *n_histogram_entries = 1;
948 (*n_histogram_entries)++;
950 *histogram_boundaries = kmalloc_array(*n_histogram_entries,
951 sizeof(unsigned long long),
953 if (!*histogram_boundaries)
959 unsigned long long hi;
962 s = sscanf(h, "%llu%c", &hi, &ch);
963 if (!s || (s == 2 && ch != ','))
968 (*histogram_boundaries)[n] = hi;
971 h = strchr(h, ',') + 1;
976 static int message_stats_create(struct mapped_device *md,
977 unsigned argc, char **argv,
978 char *result, unsigned maxlen)
983 unsigned long long start, end, len, step;
985 const char *program_id, *aux_data;
986 unsigned stat_flags = 0;
988 unsigned n_histogram_entries = 0;
989 unsigned long long *histogram_boundaries = NULL;
991 struct dm_arg_set as, as_backup;
993 unsigned feature_args;
997 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
1005 dm_consume_args(&as, 1);
1007 a = dm_shift_arg(&as);
1008 if (!strcmp(a, "-")) {
1010 len = dm_get_size(md);
1013 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
1014 start != (sector_t)start || len != (sector_t)len)
1021 a = dm_shift_arg(&as);
1022 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1026 if (do_div(step, divisor))
1030 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1031 step != (sector_t)step || !step)
1035 a = dm_shift_arg(&as);
1036 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1037 while (feature_args--) {
1038 a = dm_shift_arg(&as);
1041 if (!strcasecmp(a, "precise_timestamps"))
1042 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1043 else if (!strncasecmp(a, "histogram:", 10)) {
1044 if (n_histogram_entries)
1046 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1058 a = dm_shift_arg(&as);
1062 a = dm_shift_arg(&as);
1070 * If a buffer overflow happens after we created the region,
1071 * it's too late (the userspace would retry with a larger
1072 * buffer, but the region id that caused the overflow is already
1073 * leaked). So we must detect buffer overflow in advance.
1075 snprintf(result, maxlen, "%d", INT_MAX);
1076 if (dm_message_test_buffer_overflow(result, maxlen)) {
1081 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1082 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1083 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1089 snprintf(result, maxlen, "%d", id);
1097 kfree(histogram_boundaries);
1101 static int message_stats_delete(struct mapped_device *md,
1102 unsigned argc, char **argv)
1110 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1113 return dm_stats_delete(dm_get_stats(md), id);
1116 static int message_stats_clear(struct mapped_device *md,
1117 unsigned argc, char **argv)
1125 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1128 return dm_stats_clear(dm_get_stats(md), id);
1131 static int message_stats_list(struct mapped_device *md,
1132 unsigned argc, char **argv,
1133 char *result, unsigned maxlen)
1136 const char *program = NULL;
1138 if (argc < 1 || argc > 2)
1142 program = kstrdup(argv[1], GFP_KERNEL);
1147 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1154 static int message_stats_print(struct mapped_device *md,
1155 unsigned argc, char **argv, bool clear,
1156 char *result, unsigned maxlen)
1160 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1162 if (argc != 2 && argc != 4)
1165 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1169 if (strcmp(argv[2], "-") &&
1170 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1172 if (strcmp(argv[3], "-") &&
1173 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1177 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1181 static int message_stats_set_aux(struct mapped_device *md,
1182 unsigned argc, char **argv)
1190 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1193 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1196 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1197 char *result, unsigned maxlen)
1201 /* All messages here must start with '@' */
1202 if (!strcasecmp(argv[0], "@stats_create"))
1203 r = message_stats_create(md, argc, argv, result, maxlen);
1204 else if (!strcasecmp(argv[0], "@stats_delete"))
1205 r = message_stats_delete(md, argc, argv);
1206 else if (!strcasecmp(argv[0], "@stats_clear"))
1207 r = message_stats_clear(md, argc, argv);
1208 else if (!strcasecmp(argv[0], "@stats_list"))
1209 r = message_stats_list(md, argc, argv, result, maxlen);
1210 else if (!strcasecmp(argv[0], "@stats_print"))
1211 r = message_stats_print(md, argc, argv, false, result, maxlen);
1212 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1213 r = message_stats_print(md, argc, argv, true, result, maxlen);
1214 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1215 r = message_stats_set_aux(md, argc, argv);
1217 return 2; /* this wasn't a stats message */
1220 DMWARN("Invalid parameters for message %s", argv[0]);
1225 int __init dm_statistics_init(void)
1227 shared_memory_amount = 0;
1228 dm_stat_need_rcu_barrier = 0;
1232 void dm_statistics_exit(void)
1234 if (dm_stat_need_rcu_barrier)
1236 if (WARN_ON(shared_memory_amount))
1237 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1240 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1241 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");