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 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
153 free_shared_memory(alloc_size);
158 static void dm_kvfree(void *ptr, size_t alloc_size)
163 free_shared_memory(alloc_size);
168 static void dm_stat_free(struct rcu_head *head)
171 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
173 kfree(s->histogram_boundaries);
174 kfree(s->program_id);
176 for_each_possible_cpu(cpu) {
177 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
178 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
180 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
181 dm_kvfree(s, s->shared_alloc_size);
184 static int dm_stat_in_flight(struct dm_stat_shared *shared)
186 return atomic_read(&shared->in_flight[READ]) +
187 atomic_read(&shared->in_flight[WRITE]);
190 void dm_stats_init(struct dm_stats *stats)
193 struct dm_stats_last_position *last;
195 mutex_init(&stats->mutex);
196 INIT_LIST_HEAD(&stats->list);
197 stats->last = alloc_percpu(struct dm_stats_last_position);
198 for_each_possible_cpu(cpu) {
199 last = per_cpu_ptr(stats->last, cpu);
200 last->last_sector = (sector_t)ULLONG_MAX;
201 last->last_rw = UINT_MAX;
205 void dm_stats_cleanup(struct dm_stats *stats)
209 struct dm_stat_shared *shared;
211 while (!list_empty(&stats->list)) {
212 s = container_of(stats->list.next, struct dm_stat, list_entry);
213 list_del(&s->list_entry);
214 for (ni = 0; ni < s->n_entries; ni++) {
215 shared = &s->stat_shared[ni];
216 if (WARN_ON(dm_stat_in_flight(shared))) {
217 DMCRIT("leaked in-flight counter at index %lu "
218 "(start %llu, end %llu, step %llu): reads %d, writes %d",
220 (unsigned long long)s->start,
221 (unsigned long long)s->end,
222 (unsigned long long)s->step,
223 atomic_read(&shared->in_flight[READ]),
224 atomic_read(&shared->in_flight[WRITE]));
227 dm_stat_free(&s->rcu_head);
229 free_percpu(stats->last);
232 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
233 sector_t step, unsigned stat_flags,
234 unsigned n_histogram_entries,
235 unsigned long long *histogram_boundaries,
236 const char *program_id, const char *aux_data,
237 void (*suspend_callback)(struct mapped_device *),
238 void (*resume_callback)(struct mapped_device *),
239 struct mapped_device *md)
242 struct dm_stat *s, *tmp_s;
245 size_t shared_alloc_size;
246 size_t percpu_alloc_size;
247 size_t histogram_alloc_size;
248 struct dm_stat_percpu *p;
253 if (end < start || !step)
256 n_entries = end - start;
257 if (dm_sector_div64(n_entries, step))
260 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
263 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
264 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
267 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
268 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
271 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
272 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
275 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
276 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
279 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
283 s->stat_flags = stat_flags;
284 s->n_entries = n_entries;
288 s->shared_alloc_size = shared_alloc_size;
289 s->percpu_alloc_size = percpu_alloc_size;
290 s->histogram_alloc_size = histogram_alloc_size;
292 s->n_histogram_entries = n_histogram_entries;
293 s->histogram_boundaries = kmemdup(histogram_boundaries,
294 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
295 if (!s->histogram_boundaries) {
300 s->program_id = kstrdup(program_id, GFP_KERNEL);
301 if (!s->program_id) {
305 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
311 for (ni = 0; ni < n_entries; ni++) {
312 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
313 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
316 if (s->n_histogram_entries) {
317 unsigned long long *hi;
318 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
323 for (ni = 0; ni < n_entries; ni++) {
324 s->stat_shared[ni].tmp.histogram = hi;
325 hi += s->n_histogram_entries + 1;
329 for_each_possible_cpu(cpu) {
330 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
335 s->stat_percpu[cpu] = p;
336 if (s->n_histogram_entries) {
337 unsigned long long *hi;
338 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
343 for (ni = 0; ni < n_entries; ni++) {
344 p[ni].histogram = hi;
345 hi += s->n_histogram_entries + 1;
351 * Suspend/resume to make sure there is no i/o in flight,
352 * so that newly created statistics will be exact.
354 * (note: we couldn't suspend earlier because we must not
355 * allocate memory while suspended)
357 suspend_callback(md);
359 mutex_lock(&stats->mutex);
361 list_for_each(l, &stats->list) {
362 tmp_s = container_of(l, struct dm_stat, list_entry);
363 if (WARN_ON(tmp_s->id < s->id)) {
365 goto out_unlock_resume;
367 if (tmp_s->id > s->id)
369 if (unlikely(s->id == INT_MAX)) {
371 goto out_unlock_resume;
376 list_add_tail_rcu(&s->list_entry, l);
377 mutex_unlock(&stats->mutex);
384 mutex_unlock(&stats->mutex);
387 dm_stat_free(&s->rcu_head);
391 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
395 list_for_each_entry(s, &stats->list, list_entry) {
405 static int dm_stats_delete(struct dm_stats *stats, int id)
410 mutex_lock(&stats->mutex);
412 s = __dm_stats_find(stats, id);
414 mutex_unlock(&stats->mutex);
418 list_del_rcu(&s->list_entry);
419 mutex_unlock(&stats->mutex);
422 * vfree can't be called from RCU callback
424 for_each_possible_cpu(cpu)
425 if (is_vmalloc_addr(s->stat_percpu) ||
426 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
428 if (is_vmalloc_addr(s) ||
429 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
431 synchronize_rcu_expedited();
432 dm_stat_free(&s->rcu_head);
434 ACCESS_ONCE(dm_stat_need_rcu_barrier) = 1;
435 call_rcu(&s->rcu_head, dm_stat_free);
440 static int dm_stats_list(struct dm_stats *stats, const char *program,
441 char *result, unsigned maxlen)
449 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
452 mutex_lock(&stats->mutex);
453 list_for_each_entry(s, &stats->list, list_entry) {
454 if (!program || !strcmp(program, s->program_id)) {
455 len = s->end - s->start;
456 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
457 (unsigned long long)s->start,
458 (unsigned long long)len,
459 (unsigned long long)s->step,
462 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
463 DMEMIT(" precise_timestamps");
464 if (s->n_histogram_entries) {
466 DMEMIT(" histogram:");
467 for (i = 0; i < s->n_histogram_entries; i++) {
470 DMEMIT("%llu", s->histogram_boundaries[i]);
476 mutex_unlock(&stats->mutex);
481 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
482 struct dm_stat_percpu *p)
485 * This is racy, but so is part_round_stats_single.
487 unsigned long long now, difference;
488 unsigned in_flight_read, in_flight_write;
490 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
493 now = ktime_to_ns(ktime_get());
495 difference = now - shared->stamp;
499 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
500 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
502 p->io_ticks[READ] += difference;
504 p->io_ticks[WRITE] += difference;
505 if (in_flight_read + in_flight_write) {
506 p->io_ticks_total += difference;
507 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
512 static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
513 int idx, sector_t len,
514 struct dm_stats_aux *stats_aux, bool end,
515 unsigned long duration_jiffies)
517 struct dm_stat_shared *shared = &s->stat_shared[entry];
518 struct dm_stat_percpu *p;
521 * For strict correctness we should use local_irq_save/restore
522 * instead of preempt_disable/enable.
524 * preempt_disable/enable is racy if the driver finishes bios
525 * from non-interrupt context as well as from interrupt context
526 * or from more different interrupts.
528 * On 64-bit architectures the race only results in not counting some
529 * events, so it is acceptable. On 32-bit architectures the race could
530 * cause the counter going off by 2^32, so we need to do proper locking
533 * part_stat_lock()/part_stat_unlock() have this race too.
535 #if BITS_PER_LONG == 32
537 local_irq_save(flags);
541 p = &s->stat_percpu[smp_processor_id()][entry];
544 dm_stat_round(s, shared, p);
545 atomic_inc(&shared->in_flight[idx]);
547 unsigned long long duration;
548 dm_stat_round(s, shared, p);
549 atomic_dec(&shared->in_flight[idx]);
550 p->sectors[idx] += len;
552 p->merges[idx] += stats_aux->merged;
553 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
554 p->ticks[idx] += duration_jiffies;
555 duration = jiffies_to_msecs(duration_jiffies);
557 p->ticks[idx] += stats_aux->duration_ns;
558 duration = stats_aux->duration_ns;
560 if (s->n_histogram_entries) {
561 unsigned lo = 0, hi = s->n_histogram_entries + 1;
562 while (lo + 1 < hi) {
563 unsigned mid = (lo + hi) / 2;
564 if (s->histogram_boundaries[mid - 1] > duration) {
575 #if BITS_PER_LONG == 32
576 local_irq_restore(flags);
582 static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
583 sector_t bi_sector, sector_t end_sector,
584 bool end, unsigned long duration_jiffies,
585 struct dm_stats_aux *stats_aux)
587 sector_t rel_sector, offset, todo, fragment_len;
590 if (end_sector <= s->start || bi_sector >= s->end)
592 if (unlikely(bi_sector < s->start)) {
594 todo = end_sector - s->start;
596 rel_sector = bi_sector - s->start;
597 todo = end_sector - bi_sector;
599 if (unlikely(end_sector > s->end))
600 todo -= (end_sector - s->end);
602 offset = dm_sector_div64(rel_sector, s->step);
605 if (WARN_ON_ONCE(entry >= s->n_entries)) {
606 DMCRIT("Invalid area access in region id %d", s->id);
610 if (fragment_len > s->step - offset)
611 fragment_len = s->step - offset;
612 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
613 stats_aux, end, duration_jiffies);
614 todo -= fragment_len;
617 } while (unlikely(todo != 0));
620 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
621 sector_t bi_sector, unsigned bi_sectors, bool end,
622 unsigned long duration_jiffies,
623 struct dm_stats_aux *stats_aux)
627 struct dm_stats_last_position *last;
628 bool got_precise_time;
630 if (unlikely(!bi_sectors))
633 end_sector = bi_sector + bi_sectors;
637 * A race condition can at worst result in the merged flag being
638 * misrepresented, so we don't have to disable preemption here.
640 last = raw_cpu_ptr(stats->last);
642 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
644 (ACCESS_ONCE(last->last_rw) == WRITE))
646 ACCESS_ONCE(last->last_sector) = end_sector;
647 ACCESS_ONCE(last->last_rw) = bi_rw;
652 got_precise_time = false;
653 list_for_each_entry_rcu(s, &stats->list, list_entry) {
654 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
656 stats_aux->duration_ns = ktime_to_ns(ktime_get());
658 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
659 got_precise_time = true;
661 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
667 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
668 struct dm_stat *s, size_t x)
671 struct dm_stat_percpu *p;
674 p = &s->stat_percpu[smp_processor_id()][x];
675 dm_stat_round(s, shared, p);
678 shared->tmp.sectors[READ] = 0;
679 shared->tmp.sectors[WRITE] = 0;
680 shared->tmp.ios[READ] = 0;
681 shared->tmp.ios[WRITE] = 0;
682 shared->tmp.merges[READ] = 0;
683 shared->tmp.merges[WRITE] = 0;
684 shared->tmp.ticks[READ] = 0;
685 shared->tmp.ticks[WRITE] = 0;
686 shared->tmp.io_ticks[READ] = 0;
687 shared->tmp.io_ticks[WRITE] = 0;
688 shared->tmp.io_ticks_total = 0;
689 shared->tmp.time_in_queue = 0;
691 if (s->n_histogram_entries)
692 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
694 for_each_possible_cpu(cpu) {
695 p = &s->stat_percpu[cpu][x];
696 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
697 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
698 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
699 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
700 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
701 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
702 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
703 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
704 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
705 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
706 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
707 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
708 if (s->n_histogram_entries) {
710 for (i = 0; i < s->n_histogram_entries + 1; i++)
711 shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]);
716 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
717 bool init_tmp_percpu_totals)
720 struct dm_stat_shared *shared;
721 struct dm_stat_percpu *p;
723 for (x = idx_start; x < idx_end; x++) {
724 shared = &s->stat_shared[x];
725 if (init_tmp_percpu_totals)
726 __dm_stat_init_temporary_percpu_totals(shared, s, x);
728 p = &s->stat_percpu[smp_processor_id()][x];
729 p->sectors[READ] -= shared->tmp.sectors[READ];
730 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
731 p->ios[READ] -= shared->tmp.ios[READ];
732 p->ios[WRITE] -= shared->tmp.ios[WRITE];
733 p->merges[READ] -= shared->tmp.merges[READ];
734 p->merges[WRITE] -= shared->tmp.merges[WRITE];
735 p->ticks[READ] -= shared->tmp.ticks[READ];
736 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
737 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
738 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
739 p->io_ticks_total -= shared->tmp.io_ticks_total;
740 p->time_in_queue -= shared->tmp.time_in_queue;
742 if (s->n_histogram_entries) {
744 for (i = 0; i < s->n_histogram_entries + 1; i++) {
746 p = &s->stat_percpu[smp_processor_id()][x];
747 p->histogram[i] -= shared->tmp.histogram[i];
754 static int dm_stats_clear(struct dm_stats *stats, int id)
758 mutex_lock(&stats->mutex);
760 s = __dm_stats_find(stats, id);
762 mutex_unlock(&stats->mutex);
766 __dm_stat_clear(s, 0, s->n_entries, true);
768 mutex_unlock(&stats->mutex);
774 * This is like jiffies_to_msec, but works for 64-bit values.
776 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
778 unsigned long long result;
781 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
786 result = jiffies_to_msecs(j & 0x3fffff);
788 mult = jiffies_to_msecs(1 << 22);
789 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
792 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
797 static int dm_stats_print(struct dm_stats *stats, int id,
798 size_t idx_start, size_t idx_len,
799 bool clear, char *result, unsigned maxlen)
804 sector_t start, end, step;
806 struct dm_stat_shared *shared;
810 * <start_sector>+<length> counters
813 mutex_lock(&stats->mutex);
815 s = __dm_stats_find(stats, id);
817 mutex_unlock(&stats->mutex);
821 idx_end = idx_start + idx_len;
822 if (idx_end < idx_start ||
823 idx_end > s->n_entries)
824 idx_end = s->n_entries;
826 if (idx_start > idx_end)
830 start = s->start + (step * idx_start);
832 for (x = idx_start; x < idx_end; x++, start = end) {
833 shared = &s->stat_shared[x];
835 if (unlikely(end > s->end))
838 __dm_stat_init_temporary_percpu_totals(shared, s, x);
840 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
841 (unsigned long long)start,
842 (unsigned long long)step,
843 shared->tmp.ios[READ],
844 shared->tmp.merges[READ],
845 shared->tmp.sectors[READ],
846 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
847 shared->tmp.ios[WRITE],
848 shared->tmp.merges[WRITE],
849 shared->tmp.sectors[WRITE],
850 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
851 dm_stat_in_flight(shared),
852 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
853 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
854 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
855 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
856 if (s->n_histogram_entries) {
858 for (i = 0; i < s->n_histogram_entries + 1; i++) {
859 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
864 if (unlikely(sz + 1 >= maxlen))
865 goto buffer_overflow;
869 __dm_stat_clear(s, idx_start, idx_end, false);
872 mutex_unlock(&stats->mutex);
877 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
880 const char *new_aux_data;
882 mutex_lock(&stats->mutex);
884 s = __dm_stats_find(stats, id);
886 mutex_unlock(&stats->mutex);
890 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
892 mutex_unlock(&stats->mutex);
897 s->aux_data = new_aux_data;
899 mutex_unlock(&stats->mutex);
904 static int parse_histogram(const char *h, unsigned *n_histogram_entries,
905 unsigned long long **histogram_boundaries)
909 unsigned long long last;
911 *n_histogram_entries = 1;
914 (*n_histogram_entries)++;
916 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
917 if (!*histogram_boundaries)
923 unsigned long long hi;
926 s = sscanf(h, "%llu%c", &hi, &ch);
927 if (!s || (s == 2 && ch != ','))
932 (*histogram_boundaries)[n] = hi;
935 h = strchr(h, ',') + 1;
940 static int message_stats_create(struct mapped_device *md,
941 unsigned argc, char **argv,
942 char *result, unsigned maxlen)
947 unsigned long long start, end, len, step;
949 const char *program_id, *aux_data;
950 unsigned stat_flags = 0;
952 unsigned n_histogram_entries = 0;
953 unsigned long long *histogram_boundaries = NULL;
955 struct dm_arg_set as, as_backup;
957 unsigned feature_args;
961 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
969 dm_consume_args(&as, 1);
971 a = dm_shift_arg(&as);
972 if (!strcmp(a, "-")) {
974 len = dm_get_size(md);
977 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
978 start != (sector_t)start || len != (sector_t)len)
985 a = dm_shift_arg(&as);
986 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
990 if (do_div(step, divisor))
994 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
995 step != (sector_t)step || !step)
999 a = dm_shift_arg(&as);
1000 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1001 while (feature_args--) {
1002 a = dm_shift_arg(&as);
1005 if (!strcasecmp(a, "precise_timestamps"))
1006 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1007 else if (!strncasecmp(a, "histogram:", 10)) {
1008 if (n_histogram_entries)
1010 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
1022 a = dm_shift_arg(&as);
1026 a = dm_shift_arg(&as);
1034 * If a buffer overflow happens after we created the region,
1035 * it's too late (the userspace would retry with a larger
1036 * buffer, but the region id that caused the overflow is already
1037 * leaked). So we must detect buffer overflow in advance.
1039 snprintf(result, maxlen, "%d", INT_MAX);
1040 if (dm_message_test_buffer_overflow(result, maxlen)) {
1045 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1046 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1047 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1053 snprintf(result, maxlen, "%d", id);
1061 kfree(histogram_boundaries);
1065 static int message_stats_delete(struct mapped_device *md,
1066 unsigned argc, char **argv)
1074 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1077 return dm_stats_delete(dm_get_stats(md), id);
1080 static int message_stats_clear(struct mapped_device *md,
1081 unsigned argc, char **argv)
1089 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1092 return dm_stats_clear(dm_get_stats(md), id);
1095 static int message_stats_list(struct mapped_device *md,
1096 unsigned argc, char **argv,
1097 char *result, unsigned maxlen)
1100 const char *program = NULL;
1102 if (argc < 1 || argc > 2)
1106 program = kstrdup(argv[1], GFP_KERNEL);
1111 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1118 static int message_stats_print(struct mapped_device *md,
1119 unsigned argc, char **argv, bool clear,
1120 char *result, unsigned maxlen)
1124 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1126 if (argc != 2 && argc != 4)
1129 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1133 if (strcmp(argv[2], "-") &&
1134 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1136 if (strcmp(argv[3], "-") &&
1137 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1141 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1145 static int message_stats_set_aux(struct mapped_device *md,
1146 unsigned argc, char **argv)
1154 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1157 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1160 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
1161 char *result, unsigned maxlen)
1165 /* All messages here must start with '@' */
1166 if (!strcasecmp(argv[0], "@stats_create"))
1167 r = message_stats_create(md, argc, argv, result, maxlen);
1168 else if (!strcasecmp(argv[0], "@stats_delete"))
1169 r = message_stats_delete(md, argc, argv);
1170 else if (!strcasecmp(argv[0], "@stats_clear"))
1171 r = message_stats_clear(md, argc, argv);
1172 else if (!strcasecmp(argv[0], "@stats_list"))
1173 r = message_stats_list(md, argc, argv, result, maxlen);
1174 else if (!strcasecmp(argv[0], "@stats_print"))
1175 r = message_stats_print(md, argc, argv, false, result, maxlen);
1176 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1177 r = message_stats_print(md, argc, argv, true, result, maxlen);
1178 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1179 r = message_stats_set_aux(md, argc, argv);
1181 return 2; /* this wasn't a stats message */
1184 DMWARN("Invalid parameters for message %s", argv[0]);
1189 int __init dm_statistics_init(void)
1191 shared_memory_amount = 0;
1192 dm_stat_need_rcu_barrier = 0;
1196 void dm_statistics_exit(void)
1198 if (dm_stat_need_rcu_barrier)
1200 if (WARN_ON(shared_memory_amount))
1201 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1204 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
1205 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");