drivers/md/dm-stats.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef DM_STATS_H
   3 #define DM_STATS_H
   4
   5 #include <linux/types.h>
   6 #include <linux/mutex.h>
   7 #include <linux/list.h>
   8
   9 int dm_statistics_init(void);
  10 void dm_statistics_exit(void);
  11
  12 struct dm_stats {
  13         struct mutex mutex;
  14         struct list_head list;  /* list of struct dm_stat */
  15         struct dm_stats_last_position __percpu *last;
  16         bool precise_timestamps;
  17 };
  18
  19 struct dm_stats_aux {
  20         bool merged;
  21         unsigned long long duration_ns;
  22 };
  23
  24 void dm_stats_init(struct dm_stats *st);
  25 void dm_stats_cleanup(struct dm_stats *st);
  26
  27 struct mapped_device;
  28
  29 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
  30                      char *result, unsigned maxlen);
  31
  32 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
  33                          sector_t bi_sector, unsigned bi_sectors, bool end,
  34                          unsigned long duration_jiffies,
  35                          struct dm_stats_aux *aux);
  36
  37 static inline bool dm_stats_used(struct dm_stats *st)
  38 {
  39         return !list_empty(&st->list);
  40 }
  41
  42 static inline void dm_stats_record_start(struct dm_stats *stats, struct dm_stats_aux *aux)
  43 {
  44         if (unlikely(stats->precise_timestamps))
  45                 aux->duration_ns = ktime_to_ns(ktime_get());
  46 }
  47
  48 #endif