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->last = alloc_percpu(struct dm_stats_last_position);
199 for_each_possible_cpu(cpu) {
200 last = per_cpu_ptr(stats->last, cpu);
201 last->last_sector = (sector_t)ULLONG_MAX;
202 last->last_rw = UINT_MAX;
206 void dm_stats_cleanup(struct dm_stats *stats)
210 struct dm_stat_shared *shared;
212 while (!list_empty(&stats->list)) {
213 s = container_of(stats->list.next, struct dm_stat, list_entry);
214 list_del(&s->list_entry);
215 for (ni = 0; ni < s->n_entries; ni++) {
216 shared = &s->stat_shared[ni];
217 if (WARN_ON(dm_stat_in_flight(shared))) {
218 DMCRIT("leaked in-flight counter at index %lu "
219 "(start %llu, end %llu, step %llu): reads %d, writes %d",
221 (unsigned long long)s->start,
222 (unsigned long long)s->end,
223 (unsigned long long)s->step,
224 atomic_read(&shared->in_flight[READ]),
225 atomic_read(&shared->in_flight[WRITE]));
229 dm_stat_free(&s->rcu_head);
231 free_percpu(stats->last);
232 mutex_destroy(&stats->mutex);
235 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
236 sector_t step, unsigned stat_flags,
237 unsigned n_histogram_entries,
238 unsigned long long *histogram_boundaries,
239 const char *program_id, const char *aux_data,
240 void (*suspend_callback)(struct mapped_device *),
241 void (*resume_callback)(struct mapped_device *),
242 struct mapped_device *md)
245 struct dm_stat *s, *tmp_s;
248 size_t shared_alloc_size;
249 size_t percpu_alloc_size;
250 size_t histogram_alloc_size;
251 struct dm_stat_percpu *p;
256 if (end < start || !step)
259 n_entries = end - start;
260 if (dm_sector_div64(n_entries, step))
263 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
266 shared_alloc_size = struct_size(s, stat_shared, n_entries);
267 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
270 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
271 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
274 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
275 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
278 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
279 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
282 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
286 s->stat_flags = stat_flags;
287 s->n_entries = n_entries;
291 s->shared_alloc_size = shared_alloc_size;
292 s->percpu_alloc_size = percpu_alloc_size;
293 s->histogram_alloc_size = histogram_alloc_size;
295 s->n_histogram_entries = n_histogram_entries;
296 s->histogram_boundaries = kmemdup(histogram_boundaries,
297 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
298 if (!s->histogram_boundaries) {
303 s->program_id = kstrdup(program_id, GFP_KERNEL);
304 if (!s->program_id) {
308 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
314 for (ni = 0; ni < n_entries; ni++) {
315 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
316 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;
334 for_each_possible_cpu(cpu) {
335 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
340 s->stat_percpu[cpu] = p;
341 if (s->n_histogram_entries) {
342 unsigned long long *hi;
343 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
348 for (ni = 0; ni < n_entries; ni++) {
349 p[ni].histogram = hi;
350 hi += s->n_histogram_entries + 1;
357 * Suspend/resume to make sure there is no i/o in flight,
358 * so that newly created statistics will be exact.
360 * (note: we couldn't suspend earlier because we must not
361 * allocate memory while suspended)
363 suspend_callback(md);
365 mutex_lock(&stats->mutex);
367 list_for_each(l, &stats->list) {
368 tmp_s = container_of(l, struct dm_stat, list_entry);
369 if (WARN_ON(tmp_s->id < s->id)) {
371 goto out_unlock_resume;
373 if (tmp_s->id > s->id)
375 if (unlikely(s->id == INT_MAX)) {
377 goto out_unlock_resume;
382 list_add_tail_rcu(&s->list_entry, l);
383 mutex_unlock(&stats->mutex);
390 mutex_unlock(&stats->mutex);
393 dm_stat_free(&s->rcu_head);
397 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
401 list_for_each_entry(s, &stats->list, list_entry) {
411 static int dm_stats_delete(struct dm_stats *stats, int id)
416 mutex_lock(&stats->mutex);
418 s = __dm_stats_find(stats, id);
420 mutex_unlock(&stats->mutex);
424 list_del_rcu(&s->list_entry);
425 mutex_unlock(&stats->mutex);
428 * vfree can't be called from RCU callback
430 for_each_possible_cpu(cpu)
431 if (is_vmalloc_addr(s->stat_percpu) ||
432 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
434 if (is_vmalloc_addr(s) ||
435 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
437 synchronize_rcu_expedited();
438 dm_stat_free(&s->rcu_head);
440 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
441 call_rcu(&s->rcu_head, dm_stat_free);
446 static int dm_stats_list(struct dm_stats *stats, const char *program,
447 char *result, unsigned maxlen)
455 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
458 mutex_lock(&stats->mutex);
459 list_for_each_entry(s, &stats->list, list_entry) {
460 if (!program || !strcmp(program, s->program_id)) {
461 len = s->end - s->start;
462 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
463 (unsigned long long)s->start,
464 (unsigned long long)len,
465 (unsigned long long)s->step,
468 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
469 DMEMIT(" precise_timestamps");
470 if (s->n_histogram_entries) {
472 DMEMIT(" histogram:");
473 for (i = 0; i < s->n_histogram_entries; i++) {
476 DMEMIT("%llu", s->histogram_boundaries[i]);
483 mutex_unlock(&stats->mutex);
488 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
489 struct dm_stat_percpu *p)
492 * This is racy, but so is part_round_stats_single.
494 unsigned long long now, difference;
495 unsigned in_flight_read, in_flight_write;
497 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
500 now = ktime_to_ns(ktime_get());
502 difference = now - shared->stamp;
506 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
507 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
509 p->io_ticks[READ] += difference;
511 p->io_ticks[WRITE] += difference;
512 if (in_flight_read + in_flight_write) {
513 p->io_ticks_total += difference;
514 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
519 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
520 int idx, sector_t len,
521 struct dm_stats_aux *stats_aux, bool end,
522 unsigned long duration_jiffies)
524 struct dm_stat_shared *shared = &s->stat_shared[entry];
525 struct dm_stat_percpu *p;
528 * For strict correctness we should use local_irq_save/restore
529 * instead of preempt_disable/enable.
531 * preempt_disable/enable is racy if the driver finishes bios
532 * from non-interrupt context as well as from interrupt context
533 * or from more different interrupts.
535 * On 64-bit architectures the race only results in not counting some
536 * events, so it is acceptable. On 32-bit architectures the race could
537 * cause the counter going off by 2^32, so we need to do proper locking
540 * part_stat_lock()/part_stat_unlock() have this race too.
542 #if BITS_PER_LONG == 32
544 local_irq_save(flags);
548 p = &s->stat_percpu[smp_processor_id()][entry];
551 dm_stat_round(s, shared, p);
552 atomic_inc(&shared->in_flight[idx]);
554 unsigned long long duration;
555 dm_stat_round(s, shared, p);
556 atomic_dec(&shared->in_flight[idx]);
557 p->sectors[idx] += len;
559 p->merges[idx] += stats_aux->merged;
560 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
561 p->ticks[idx] += duration_jiffies;
562 duration = jiffies_to_msecs(duration_jiffies);
564 p->ticks[idx] += stats_aux->duration_ns;
565 duration = stats_aux->duration_ns;
567 if (s->n_histogram_entries) {
568 unsigned lo = 0, hi = s->n_histogram_entries + 1;
569 while (lo + 1 < hi) {
570 unsigned mid = (lo + hi) / 2;
571 if (s->histogram_boundaries[mid - 1] > duration) {
582 #if BITS_PER_LONG == 32
583 local_irq_restore(flags);
589 static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
590 sector_t bi_sector, sector_t end_sector,
591 bool end, unsigned long duration_jiffies,
592 struct dm_stats_aux *stats_aux)
594 sector_t rel_sector, offset, todo, fragment_len;
597 if (end_sector <= s->start || bi_sector >= s->end)
599 if (unlikely(bi_sector < s->start)) {
601 todo = end_sector - s->start;
603 rel_sector = bi_sector - s->start;
604 todo = end_sector - bi_sector;
606 if (unlikely(end_sector > s->end))
607 todo -= (end_sector - s->end);
609 offset = dm_sector_div64(rel_sector, s->step);
612 if (WARN_ON_ONCE(entry >= s->n_entries)) {
613 DMCRIT("Invalid area access in region id %d", s->id);
617 if (fragment_len > s->step - offset)
618 fragment_len = s->step - offset;
619 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
620 stats_aux, end, duration_jiffies);
621 todo -= fragment_len;
624 } while (unlikely(todo != 0));
627 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
628 sector_t bi_sector, unsigned bi_sectors, bool end,
629 unsigned long duration_jiffies,
630 struct dm_stats_aux *stats_aux)
634 struct dm_stats_last_position *last;
635 bool got_precise_time;
637 if (unlikely(!bi_sectors))
640 end_sector = bi_sector + bi_sectors;
644 * A race condition can at worst result in the merged flag being
645 * misrepresented, so we don't have to disable preemption here.
647 last = raw_cpu_ptr(stats->last);
649 (bi_sector == (READ_ONCE(last->last_sector) &&
651 (READ_ONCE(last->last_rw) == WRITE))
653 WRITE_ONCE(last->last_sector, end_sector);
654 WRITE_ONCE(last->last_rw, bi_rw);
659 got_precise_time = false;
660 list_for_each_entry_rcu(s, &stats->list, list_entry) {
661 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
663 stats_aux->duration_ns = ktime_to_ns(ktime_get());
665 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
666 got_precise_time = true;
668 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
674 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
675 struct dm_stat *s, size_t x)
678 struct dm_stat_percpu *p;
681 p = &s->stat_percpu[smp_processor_id()][x];
682 dm_stat_round(s, shared, p);
685 shared->tmp.sectors[READ] = 0;
686 shared->tmp.sectors[WRITE] = 0;
687 shared->tmp.ios[READ] = 0;
688 shared->tmp.ios[WRITE] = 0;
689 shared->tmp.merges[READ] = 0;
690 shared->tmp.merges[WRITE] = 0;
691 shared->tmp.ticks[READ] = 0;
692 shared->tmp.ticks[WRITE] = 0;
693 shared->tmp.io_ticks[READ] = 0;
694 shared->tmp.io_ticks[WRITE] = 0;
695 shared->tmp.io_ticks_total = 0;
696 shared->tmp.time_in_queue = 0;
698 if (s->n_histogram_entries)
699 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
701 for_each_possible_cpu(cpu) {
702 p = &s->stat_percpu[cpu][x];
703 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
704 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
705 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
706 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
707 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
708 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
709 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
710 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
711 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
712 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
713 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
714 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
715 if (s->n_histogram_entries) {
717 for (i = 0; i < s->n_histogram_entries + 1; i++)
718 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
723 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
724 bool init_tmp_percpu_totals)
727 struct dm_stat_shared *shared;
728 struct dm_stat_percpu *p;
730 for (x = idx_start; x < idx_end; x++) {
731 shared = &s->stat_shared[x];
732 if (init_tmp_percpu_totals)
733 __dm_stat_init_temporary_percpu_totals(shared, s, x);
735 p = &s->stat_percpu[smp_processor_id()][x];
736 p->sectors[READ] -= shared->tmp.sectors[READ];
737 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
738 p->ios[READ] -= shared->tmp.ios[READ];
739 p->ios[WRITE] -= shared->tmp.ios[WRITE];
740 p->merges[READ] -= shared->tmp.merges[READ];
741 p->merges[WRITE] -= shared->tmp.merges[WRITE];
742 p->ticks[READ] -= shared->tmp.ticks[READ];
743 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
744 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
745 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
746 p->io_ticks_total -= shared->tmp.io_ticks_total;
747 p->time_in_queue -= shared->tmp.time_in_queue;
749 if (s->n_histogram_entries) {
751 for (i = 0; i < s->n_histogram_entries + 1; i++) {
753 p = &s->stat_percpu[smp_processor_id()][x];
754 p->histogram[i] -= shared->tmp.histogram[i];
762 static int dm_stats_clear(struct dm_stats *stats, int id)
766 mutex_lock(&stats->mutex);
768 s = __dm_stats_find(stats, id);
770 mutex_unlock(&stats->mutex);
774 __dm_stat_clear(s, 0, s->n_entries, true);
776 mutex_unlock(&stats->mutex);
782 * This is like jiffies_to_msec, but works for 64-bit values.
784 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
786 unsigned long long result;
789 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
794 result = jiffies_to_msecs(j & 0x3fffff);
796 mult = jiffies_to_msecs(1 << 22);
797 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
800 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
805 static int dm_stats_print(struct dm_stats *stats, int id,
806 size_t idx_start, size_t idx_len,
807 bool clear, char *result, unsigned maxlen)
812 sector_t start, end, step;
814 struct dm_stat_shared *shared;
818 * <start_sector>+<length> counters
821 mutex_lock(&stats->mutex);
823 s = __dm_stats_find(stats, id);
825 mutex_unlock(&stats->mutex);
829 idx_end = idx_start + idx_len;
830 if (idx_end < idx_start ||
831 idx_end > s->n_entries)
832 idx_end = s->n_entries;
834 if (idx_start > idx_end)
838 start = s->start + (step * idx_start);
840 for (x = idx_start; x < idx_end; x++, start = end) {
841 shared = &s->stat_shared[x];
843 if (unlikely(end > s->end))
846 __dm_stat_init_temporary_percpu_totals(shared, s, x);
848 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
849 (unsigned long long)start,
850 (unsigned long long)step,
851 shared->tmp.ios[READ],
852 shared->tmp.merges[READ],
853 shared->tmp.sectors[READ],
854 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
855 shared->tmp.ios[WRITE],
856 shared->tmp.merges[WRITE],
857 shared->tmp.sectors[WRITE],
858 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
859 dm_stat_in_flight(shared),
860 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
861 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
862 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
863 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
864 if (s->n_histogram_entries) {
866 for (i = 0; i < s->n_histogram_entries + 1; i++) {
867 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
872 if (unlikely(sz + 1 >= maxlen))
873 goto buffer_overflow;
879 __dm_stat_clear(s, idx_start, idx_end, false);
882 mutex_unlock(&stats->mutex);
887 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
890 const char *new_aux_data;
892 mutex_lock(&stats->mutex);
894 s = __dm_stats_find(stats, id);
896 mutex_unlock(&stats->mutex);
900 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
902 mutex_unlock(&stats->mutex);
907 s->aux_data = new_aux_data;
909 mutex_unlock(&stats->mutex);
914 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
915 unsigned long long **histogram_boundaries)
919 unsigned long long last;
921 *n_histogram_entries = 1;
924 (*n_histogram_entries)++;
926 *histogram_boundaries = kmalloc_array(*n_histogram_entries,
927 sizeof(unsigned long long),
929 if (!*histogram_boundaries)
935 unsigned long long hi;
938 s = sscanf(h, "%llu%c", &hi, &ch);
939 if (!s || (s == 2 && ch != ','))
944 (*histogram_boundaries)[n] = hi;
947 h = strchr(h, ',') + 1;
952 static int message_stats_create(struct mapped_device *md,
953 unsigned argc, char **argv,
954 char *result, unsigned maxlen)
959 unsigned long long start, end, len, step;
961 const char *program_id, *aux_data;
962 unsigned stat_flags = 0;
964 unsigned n_histogram_entries = 0;
965 unsigned long long *histogram_boundaries = NULL;
967 struct dm_arg_set as, as_backup;
969 unsigned feature_args;
973 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
981 dm_consume_args(&as, 1);
983 a = dm_shift_arg(&as);
984 if (!strcmp(a, "-")) {
986 len = dm_get_size(md);
989 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
990 start != (sector_t)start || len != (sector_t)len)
997 a = dm_shift_arg(&as);
998 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1002 if (do_div(step, divisor))
1006 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1007 step != (sector_t)step || !step)
1011 a = dm_shift_arg(&as);
1012 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1013 while (feature_args--) {
1014 a = dm_shift_arg(&as);
1017 if (!strcasecmp(a, "precise_timestamps"))
1018 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1019 else if (!strncasecmp(a, "histogram:", 10)) {
1020 if (n_histogram_entries)
1022 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1034 a = dm_shift_arg(&as);
1038 a = dm_shift_arg(&as);
1046 * If a buffer overflow happens after we created the region,
1047 * it's too late (the userspace would retry with a larger
1048 * buffer, but the region id that caused the overflow is already
1049 * leaked). So we must detect buffer overflow in advance.
1051 snprintf(result, maxlen, "%d", INT_MAX);
1052 if (dm_message_test_buffer_overflow(result, maxlen)) {
1057 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1058 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1059 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1065 snprintf(result, maxlen, "%d", id);
1073 kfree(histogram_boundaries);
1077 static int message_stats_delete(struct mapped_device *md,
1078 unsigned argc, char **argv)
1086 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1089 return dm_stats_delete(dm_get_stats(md), id);
1092 static int message_stats_clear(struct mapped_device *md,
1093 unsigned argc, char **argv)
1101 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1104 return dm_stats_clear(dm_get_stats(md), id);
1107 static int message_stats_list(struct mapped_device *md,
1108 unsigned argc, char **argv,
1109 char *result, unsigned maxlen)
1112 const char *program = NULL;
1114 if (argc < 1 || argc > 2)
1118 program = kstrdup(argv[1], GFP_KERNEL);
1123 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1130 static int message_stats_print(struct mapped_device *md,
1131 unsigned argc, char **argv, bool clear,
1132 char *result, unsigned maxlen)
1136 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1138 if (argc != 2 && argc != 4)
1141 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1145 if (strcmp(argv[2], "-") &&
1146 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1148 if (strcmp(argv[3], "-") &&
1149 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1153 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1157 static int message_stats_set_aux(struct mapped_device *md,
1158 unsigned argc, char **argv)
1166 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1169 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1172 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1173 char *result, unsigned maxlen)
1177 /* All messages here must start with '@' */
1178 if (!strcasecmp(argv[0], "@stats_create"))
1179 r = message_stats_create(md, argc, argv, result, maxlen);
1180 else if (!strcasecmp(argv[0], "@stats_delete"))
1181 r = message_stats_delete(md, argc, argv);
1182 else if (!strcasecmp(argv[0], "@stats_clear"))
1183 r = message_stats_clear(md, argc, argv);
1184 else if (!strcasecmp(argv[0], "@stats_list"))
1185 r = message_stats_list(md, argc, argv, result, maxlen);
1186 else if (!strcasecmp(argv[0], "@stats_print"))
1187 r = message_stats_print(md, argc, argv, false, result, maxlen);
1188 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1189 r = message_stats_print(md, argc, argv, true, result, maxlen);
1190 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1191 r = message_stats_set_aux(md, argc, argv);
1193 return 2; /* this wasn't a stats message */
1196 DMWARN("Invalid parameters for message %s", argv[0]);
1201 int __init dm_statistics_init(void)
1203 shared_memory_amount = 0;
1204 dm_stat_need_rcu_barrier = 0;
1208 void dm_statistics_exit(void)
1210 if (dm_stat_need_rcu_barrier)
1212 if (WARN_ON(shared_memory_amount))
1213 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1216 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1217 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");