mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-20 03:04:01 +08:00
fd2ed4d252
Support the collection of I/O statistics on user-defined regions of a DM device. If no regions are defined no statistics are collected so there isn't any performance impact. Only bio-based DM devices are currently supported. Each user-defined region specifies a starting sector, length and step. Individual statistics will be collected for each step-sized area within the range specified. The I/O statistics counters for each step-sized area of a region are in the same format as /sys/block/*/stat or /proc/diskstats but extra counters (12 and 13) are provided: total time spent reading and writing in milliseconds. All these counters may be accessed by sending the @stats_print message to the appropriate DM device via dmsetup. The creation of DM statistics will allocate memory via kmalloc or fallback to using vmalloc space. At most, 1/4 of the overall system memory may be allocated by DM statistics. The admin can see how much memory is used by reading /sys/module/dm_mod/parameters/stats_current_allocated_bytes See Documentation/device-mapper/statistics.txt for more details. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
41 lines
904 B
C
41 lines
904 B
C
#ifndef DM_STATS_H
|
|
#define DM_STATS_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/list.h>
|
|
|
|
int dm_statistics_init(void);
|
|
void dm_statistics_exit(void);
|
|
|
|
struct dm_stats {
|
|
struct mutex mutex;
|
|
struct list_head list; /* list of struct dm_stat */
|
|
struct dm_stats_last_position __percpu *last;
|
|
sector_t last_sector;
|
|
unsigned last_rw;
|
|
};
|
|
|
|
struct dm_stats_aux {
|
|
bool merged;
|
|
};
|
|
|
|
void dm_stats_init(struct dm_stats *st);
|
|
void dm_stats_cleanup(struct dm_stats *st);
|
|
|
|
struct mapped_device;
|
|
|
|
int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
|
|
char *result, unsigned maxlen);
|
|
|
|
void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
|
|
sector_t bi_sector, unsigned bi_sectors, bool end,
|
|
unsigned long duration, struct dm_stats_aux *aux);
|
|
|
|
static inline bool dm_stats_used(struct dm_stats *st)
|
|
{
|
|
return !list_empty(&st->list);
|
|
}
|
|
|
|
#endif
|