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[0];
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 int 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);
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;
211 void dm_stats_cleanup(struct dm_stats *stats)
215 struct dm_stat_shared *shared;
217 while (!list_empty(&stats->list)) {
218 s = container_of(stats->list.next, struct dm_stat, list_entry);
219 list_del(&s->list_entry);
220 for (ni = 0; ni < s->n_entries; ni++) {
221 shared = &s->stat_shared[ni];
222 if (WARN_ON(dm_stat_in_flight(shared))) {
223 DMCRIT("leaked in-flight counter at index %lu "
224 "(start %llu, end %llu, step %llu): reads %d, writes %d",
226 (unsigned long long)s->start,
227 (unsigned long long)s->end,
228 (unsigned long long)s->step,
229 atomic_read(&shared->in_flight[READ]),
230 atomic_read(&shared->in_flight[WRITE]));
234 dm_stat_free(&s->rcu_head);
236 free_percpu(stats->last);
237 mutex_destroy(&stats->mutex);
240 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
241 sector_t step, unsigned stat_flags,
242 unsigned n_histogram_entries,
243 unsigned long long *histogram_boundaries,
244 const char *program_id, const char *aux_data,
245 void (*suspend_callback)(struct mapped_device *),
246 void (*resume_callback)(struct mapped_device *),
247 struct mapped_device *md)
250 struct dm_stat *s, *tmp_s;
253 size_t shared_alloc_size;
254 size_t percpu_alloc_size;
255 size_t histogram_alloc_size;
256 struct dm_stat_percpu *p;
261 if (end < start || !step)
264 n_entries = end - start;
265 if (dm_sector_div64(n_entries, step))
268 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
271 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
272 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
275 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
276 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
279 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
280 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
283 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
284 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
287 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
291 s->stat_flags = stat_flags;
292 s->n_entries = n_entries;
296 s->shared_alloc_size = shared_alloc_size;
297 s->percpu_alloc_size = percpu_alloc_size;
298 s->histogram_alloc_size = histogram_alloc_size;
300 s->n_histogram_entries = n_histogram_entries;
301 s->histogram_boundaries = kmemdup(histogram_boundaries,
302 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
303 if (!s->histogram_boundaries) {
308 s->program_id = kstrdup(program_id, GFP_KERNEL);
309 if (!s->program_id) {
313 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
319 for (ni = 0; ni < n_entries; ni++) {
320 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
321 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
325 if (s->n_histogram_entries) {
326 unsigned long long *hi;
327 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
332 for (ni = 0; ni < n_entries; ni++) {
333 s->stat_shared[ni].tmp.histogram = hi;
334 hi += s->n_histogram_entries + 1;
339 for_each_possible_cpu(cpu) {
340 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
345 s->stat_percpu[cpu] = p;
346 if (s->n_histogram_entries) {
347 unsigned long long *hi;
348 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
353 for (ni = 0; ni < n_entries; ni++) {
354 p[ni].histogram = hi;
355 hi += s->n_histogram_entries + 1;
362 * Suspend/resume to make sure there is no i/o in flight,
363 * so that newly created statistics will be exact.
365 * (note: we couldn't suspend earlier because we must not
366 * allocate memory while suspended)
368 suspend_callback(md);
370 mutex_lock(&stats->mutex);
372 list_for_each(l, &stats->list) {
373 tmp_s = container_of(l, struct dm_stat, list_entry);
374 if (WARN_ON(tmp_s->id < s->id)) {
376 goto out_unlock_resume;
378 if (tmp_s->id > s->id)
380 if (unlikely(s->id == INT_MAX)) {
382 goto out_unlock_resume;
387 list_add_tail_rcu(&s->list_entry, l);
388 mutex_unlock(&stats->mutex);
395 mutex_unlock(&stats->mutex);
398 dm_stat_free(&s->rcu_head);
402 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
406 list_for_each_entry(s, &stats->list, list_entry) {
416 static int dm_stats_delete(struct dm_stats *stats, int id)
421 mutex_lock(&stats->mutex);
423 s = __dm_stats_find(stats, id);
425 mutex_unlock(&stats->mutex);
429 list_del_rcu(&s->list_entry);
430 mutex_unlock(&stats->mutex);
433 * vfree can't be called from RCU callback
435 for_each_possible_cpu(cpu)
436 if (is_vmalloc_addr(s->stat_percpu) ||
437 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
439 if (is_vmalloc_addr(s) ||
440 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
442 synchronize_rcu_expedited();
443 dm_stat_free(&s->rcu_head);
445 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
446 call_rcu(&s->rcu_head, dm_stat_free);
451 static int dm_stats_list(struct dm_stats *stats, const char *program,
452 char *result, unsigned maxlen)
460 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
463 mutex_lock(&stats->mutex);
464 list_for_each_entry(s, &stats->list, list_entry) {
465 if (!program || !strcmp(program, s->program_id)) {
466 len = s->end - s->start;
467 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
468 (unsigned long long)s->start,
469 (unsigned long long)len,
470 (unsigned long long)s->step,
473 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
474 DMEMIT(" precise_timestamps");
475 if (s->n_histogram_entries) {
477 DMEMIT(" histogram:");
478 for (i = 0; i < s->n_histogram_entries; i++) {
481 DMEMIT("%llu", s->histogram_boundaries[i]);
488 mutex_unlock(&stats->mutex);
493 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
494 struct dm_stat_percpu *p)
497 * This is racy, but so is part_round_stats_single.
499 unsigned long long now, difference;
500 unsigned in_flight_read, in_flight_write;
502 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
505 now = ktime_to_ns(ktime_get());
507 difference = now - shared->stamp;
511 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
512 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
514 p->io_ticks[READ] += difference;
516 p->io_ticks[WRITE] += difference;
517 if (in_flight_read + in_flight_write) {
518 p->io_ticks_total += difference;
519 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
524 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
525 int idx, sector_t len,
526 struct dm_stats_aux *stats_aux, bool end,
527 unsigned long duration_jiffies)
529 struct dm_stat_shared *shared = &s->stat_shared[entry];
530 struct dm_stat_percpu *p;
533 * For strict correctness we should use local_irq_save/restore
534 * instead of preempt_disable/enable.
536 * preempt_disable/enable is racy if the driver finishes bios
537 * from non-interrupt context as well as from interrupt context
538 * or from more different interrupts.
540 * On 64-bit architectures the race only results in not counting some
541 * events, so it is acceptable. On 32-bit architectures the race could
542 * cause the counter going off by 2^32, so we need to do proper locking
545 * part_stat_lock()/part_stat_unlock() have this race too.
547 #if BITS_PER_LONG == 32
549 local_irq_save(flags);
553 p = &s->stat_percpu[smp_processor_id()][entry];
556 dm_stat_round(s, shared, p);
557 atomic_inc(&shared->in_flight[idx]);
559 unsigned long long duration;
560 dm_stat_round(s, shared, p);
561 atomic_dec(&shared->in_flight[idx]);
562 p->sectors[idx] += len;
564 p->merges[idx] += stats_aux->merged;
565 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
566 p->ticks[idx] += duration_jiffies;
567 duration = jiffies_to_msecs(duration_jiffies);
569 p->ticks[idx] += stats_aux->duration_ns;
570 duration = stats_aux->duration_ns;
572 if (s->n_histogram_entries) {
573 unsigned lo = 0, hi = s->n_histogram_entries + 1;
574 while (lo + 1 < hi) {
575 unsigned mid = (lo + hi) / 2;
576 if (s->histogram_boundaries[mid - 1] > duration) {
587 #if BITS_PER_LONG == 32
588 local_irq_restore(flags);
594 static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
595 sector_t bi_sector, sector_t end_sector,
596 bool end, unsigned long duration_jiffies,
597 struct dm_stats_aux *stats_aux)
599 sector_t rel_sector, offset, todo, fragment_len;
602 if (end_sector <= s->start || bi_sector >= s->end)
604 if (unlikely(bi_sector < s->start)) {
606 todo = end_sector - s->start;
608 rel_sector = bi_sector - s->start;
609 todo = end_sector - bi_sector;
611 if (unlikely(end_sector > s->end))
612 todo -= (end_sector - s->end);
614 offset = dm_sector_div64(rel_sector, s->step);
617 if (WARN_ON_ONCE(entry >= s->n_entries)) {
618 DMCRIT("Invalid area access in region id %d", s->id);
622 if (fragment_len > s->step - offset)
623 fragment_len = s->step - offset;
624 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
625 stats_aux, end, duration_jiffies);
626 todo -= fragment_len;
629 } while (unlikely(todo != 0));
632 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
633 sector_t bi_sector, unsigned bi_sectors, bool end,
634 unsigned long duration_jiffies,
635 struct dm_stats_aux *stats_aux)
639 struct dm_stats_last_position *last;
640 bool got_precise_time;
642 if (unlikely(!bi_sectors))
645 end_sector = bi_sector + bi_sectors;
649 * A race condition can at worst result in the merged flag being
650 * misrepresented, so we don't have to disable preemption here.
652 last = raw_cpu_ptr(stats->last);
654 (bi_sector == (READ_ONCE(last->last_sector) &&
656 (READ_ONCE(last->last_rw) == WRITE))
658 WRITE_ONCE(last->last_sector, end_sector);
659 WRITE_ONCE(last->last_rw, bi_rw);
664 got_precise_time = false;
665 list_for_each_entry_rcu(s, &stats->list, list_entry) {
666 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
668 stats_aux->duration_ns = ktime_to_ns(ktime_get());
670 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
671 got_precise_time = true;
673 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
679 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
680 struct dm_stat *s, size_t x)
683 struct dm_stat_percpu *p;
686 p = &s->stat_percpu[smp_processor_id()][x];
687 dm_stat_round(s, shared, p);
690 shared->tmp.sectors[READ] = 0;
691 shared->tmp.sectors[WRITE] = 0;
692 shared->tmp.ios[READ] = 0;
693 shared->tmp.ios[WRITE] = 0;
694 shared->tmp.merges[READ] = 0;
695 shared->tmp.merges[WRITE] = 0;
696 shared->tmp.ticks[READ] = 0;
697 shared->tmp.ticks[WRITE] = 0;
698 shared->tmp.io_ticks[READ] = 0;
699 shared->tmp.io_ticks[WRITE] = 0;
700 shared->tmp.io_ticks_total = 0;
701 shared->tmp.time_in_queue = 0;
703 if (s->n_histogram_entries)
704 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
706 for_each_possible_cpu(cpu) {
707 p = &s->stat_percpu[cpu][x];
708 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
709 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
710 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
711 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
712 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
713 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
714 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
715 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
716 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
717 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
718 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
719 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
720 if (s->n_histogram_entries) {
722 for (i = 0; i < s->n_histogram_entries + 1; i++)
723 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
728 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
729 bool init_tmp_percpu_totals)
732 struct dm_stat_shared *shared;
733 struct dm_stat_percpu *p;
735 for (x = idx_start; x < idx_end; x++) {
736 shared = &s->stat_shared[x];
737 if (init_tmp_percpu_totals)
738 __dm_stat_init_temporary_percpu_totals(shared, s, x);
740 p = &s->stat_percpu[smp_processor_id()][x];
741 p->sectors[READ] -= shared->tmp.sectors[READ];
742 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
743 p->ios[READ] -= shared->tmp.ios[READ];
744 p->ios[WRITE] -= shared->tmp.ios[WRITE];
745 p->merges[READ] -= shared->tmp.merges[READ];
746 p->merges[WRITE] -= shared->tmp.merges[WRITE];
747 p->ticks[READ] -= shared->tmp.ticks[READ];
748 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
749 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
750 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
751 p->io_ticks_total -= shared->tmp.io_ticks_total;
752 p->time_in_queue -= shared->tmp.time_in_queue;
754 if (s->n_histogram_entries) {
756 for (i = 0; i < s->n_histogram_entries + 1; i++) {
758 p = &s->stat_percpu[smp_processor_id()][x];
759 p->histogram[i] -= shared->tmp.histogram[i];
767 static int dm_stats_clear(struct dm_stats *stats, int id)
771 mutex_lock(&stats->mutex);
773 s = __dm_stats_find(stats, id);
775 mutex_unlock(&stats->mutex);
779 __dm_stat_clear(s, 0, s->n_entries, true);
781 mutex_unlock(&stats->mutex);
787 * This is like jiffies_to_msec, but works for 64-bit values.
789 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
791 unsigned long long result;
794 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
799 result = jiffies_to_msecs(j & 0x3fffff);
801 mult = jiffies_to_msecs(1 << 22);
802 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
805 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
810 static int dm_stats_print(struct dm_stats *stats, int id,
811 size_t idx_start, size_t idx_len,
812 bool clear, char *result, unsigned maxlen)
817 sector_t start, end, step;
819 struct dm_stat_shared *shared;
823 * <start_sector>+<length> counters
826 mutex_lock(&stats->mutex);
828 s = __dm_stats_find(stats, id);
830 mutex_unlock(&stats->mutex);
834 idx_end = idx_start + idx_len;
835 if (idx_end < idx_start ||
836 idx_end > s->n_entries)
837 idx_end = s->n_entries;
839 if (idx_start > idx_end)
843 start = s->start + (step * idx_start);
845 for (x = idx_start; x < idx_end; x++, start = end) {
846 shared = &s->stat_shared[x];
848 if (unlikely(end > s->end))
851 __dm_stat_init_temporary_percpu_totals(shared, s, x);
853 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
854 (unsigned long long)start,
855 (unsigned long long)step,
856 shared->tmp.ios[READ],
857 shared->tmp.merges[READ],
858 shared->tmp.sectors[READ],
859 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
860 shared->tmp.ios[WRITE],
861 shared->tmp.merges[WRITE],
862 shared->tmp.sectors[WRITE],
863 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
864 dm_stat_in_flight(shared),
865 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
866 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
867 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
868 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
869 if (s->n_histogram_entries) {
871 for (i = 0; i < s->n_histogram_entries + 1; i++) {
872 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
877 if (unlikely(sz + 1 >= maxlen))
878 goto buffer_overflow;
884 __dm_stat_clear(s, idx_start, idx_end, false);
887 mutex_unlock(&stats->mutex);
892 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
895 const char *new_aux_data;
897 mutex_lock(&stats->mutex);
899 s = __dm_stats_find(stats, id);
901 mutex_unlock(&stats->mutex);
905 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
907 mutex_unlock(&stats->mutex);
912 s->aux_data = new_aux_data;
914 mutex_unlock(&stats->mutex);
919 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
920 unsigned long long **histogram_boundaries)
924 unsigned long long last;
926 *n_histogram_entries = 1;
929 (*n_histogram_entries)++;
931 *histogram_boundaries = kmalloc_array(*n_histogram_entries,
932 sizeof(unsigned long long),
934 if (!*histogram_boundaries)
940 unsigned long long hi;
943 s = sscanf(h, "%llu%c", &hi, &ch);
944 if (!s || (s == 2 && ch != ','))
949 (*histogram_boundaries)[n] = hi;
952 h = strchr(h, ',') + 1;
957 static int message_stats_create(struct mapped_device *md,
958 unsigned argc, char **argv,
959 char *result, unsigned maxlen)
964 unsigned long long start, end, len, step;
966 const char *program_id, *aux_data;
967 unsigned stat_flags = 0;
969 unsigned n_histogram_entries = 0;
970 unsigned long long *histogram_boundaries = NULL;
972 struct dm_arg_set as, as_backup;
974 unsigned feature_args;
978 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
986 dm_consume_args(&as, 1);
988 a = dm_shift_arg(&as);
989 if (!strcmp(a, "-")) {
991 len = dm_get_size(md);
994 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
995 start != (sector_t)start || len != (sector_t)len)
1002 a = dm_shift_arg(&as);
1003 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1007 if (do_div(step, divisor))
1011 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1012 step != (sector_t)step || !step)
1016 a = dm_shift_arg(&as);
1017 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1018 while (feature_args--) {
1019 a = dm_shift_arg(&as);
1022 if (!strcasecmp(a, "precise_timestamps"))
1023 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1024 else if (!strncasecmp(a, "histogram:", 10)) {
1025 if (n_histogram_entries)
1027 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1039 a = dm_shift_arg(&as);
1043 a = dm_shift_arg(&as);
1051 * If a buffer overflow happens after we created the region,
1052 * it's too late (the userspace would retry with a larger
1053 * buffer, but the region id that caused the overflow is already
1054 * leaked). So we must detect buffer overflow in advance.
1056 snprintf(result, maxlen, "%d", INT_MAX);
1057 if (dm_message_test_buffer_overflow(result, maxlen)) {
1062 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1063 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1064 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1070 snprintf(result, maxlen, "%d", id);
1078 kfree(histogram_boundaries);
1082 static int message_stats_delete(struct mapped_device *md,
1083 unsigned argc, char **argv)
1091 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1094 return dm_stats_delete(dm_get_stats(md), id);
1097 static int message_stats_clear(struct mapped_device *md,
1098 unsigned argc, char **argv)
1106 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1109 return dm_stats_clear(dm_get_stats(md), id);
1112 static int message_stats_list(struct mapped_device *md,
1113 unsigned argc, char **argv,
1114 char *result, unsigned maxlen)
1117 const char *program = NULL;
1119 if (argc < 1 || argc > 2)
1123 program = kstrdup(argv[1], GFP_KERNEL);
1128 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1135 static int message_stats_print(struct mapped_device *md,
1136 unsigned argc, char **argv, bool clear,
1137 char *result, unsigned maxlen)
1141 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1143 if (argc != 2 && argc != 4)
1146 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1150 if (strcmp(argv[2], "-") &&
1151 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1153 if (strcmp(argv[3], "-") &&
1154 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1158 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1162 static int message_stats_set_aux(struct mapped_device *md,
1163 unsigned argc, char **argv)
1171 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1174 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1177 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1178 char *result, unsigned maxlen)
1182 /* All messages here must start with '@' */
1183 if (!strcasecmp(argv[0], "@stats_create"))
1184 r = message_stats_create(md, argc, argv, result, maxlen);
1185 else if (!strcasecmp(argv[0], "@stats_delete"))
1186 r = message_stats_delete(md, argc, argv);
1187 else if (!strcasecmp(argv[0], "@stats_clear"))
1188 r = message_stats_clear(md, argc, argv);
1189 else if (!strcasecmp(argv[0], "@stats_list"))
1190 r = message_stats_list(md, argc, argv, result, maxlen);
1191 else if (!strcasecmp(argv[0], "@stats_print"))
1192 r = message_stats_print(md, argc, argv, false, result, maxlen);
1193 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1194 r = message_stats_print(md, argc, argv, true, result, maxlen);
1195 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1196 r = message_stats_set_aux(md, argc, argv);
1198 return 2; /* this wasn't a stats message */
1201 DMWARN("Invalid parameters for message %s", argv[0]);
1206 int __init dm_statistics_init(void)
1208 shared_memory_amount = 0;
1209 dm_stat_need_rcu_barrier = 0;
1213 void dm_statistics_exit(void)
1215 if (dm_stat_need_rcu_barrier)
1217 if (WARN_ON(shared_memory_amount))
1218 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1221 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1222 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");