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dm stats: add support for request-based DM devices 

This makes it possible to use dm stats with DM multipath.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2015-06-09 17:22:49 -04:00 committed by Mike Snitzer
parent dfcfac3e4c
commit e262f34741
2 changed files with 26 additions and 5 deletions
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5
drivers/md/dm-stats.c
View File

@ -1155,11 +1155,6 @@ int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
{
int r;
if (dm_request_based(md)) {
DMWARN("Statistics are only supported for bio-based devices");
return -EOPNOTSUPP;
}
/* All messages here must start with '@' */
if (!strcasecmp(argv[0], "@stats_create"))
r = message_stats_create(md, argc, argv, result, maxlen);

26
drivers/md/dm.c
View File

@ -86,6 +86,9 @@ struct dm_rq_target_io {
struct kthread_work work;
int error;
union map_info info;
struct dm_stats_aux stats_aux;
unsigned long duration_jiffies;
unsigned n_sectors;
};
/*
@ -995,6 +998,17 @@ static struct dm_rq_target_io *tio_from_request(struct request *rq)
return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);
}
static void rq_end_stats(struct mapped_device *md, struct request *orig)
{
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies - tio->duration_jiffies;
dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),
tio->n_sectors, true, tio->duration_jiffies,
&tio->stats_aux);
}
}
/*
* Don't touch any member of the md after calling this function because
* the md may be freed in dm_put() at the end of this function.
@ -1078,6 +1092,7 @@ static void dm_end_request(struct request *clone, int error)
}
free_rq_clone(clone);
rq_end_stats(md, rq);
if (!rq->q->mq_ops)
blk_end_request_all(rq, error);
else
@ -1120,6 +1135,7 @@ static void dm_requeue_original_request(struct mapped_device *md,
dm_unprep_request(rq);
rq_end_stats(md, rq);
if (!rq->q->mq_ops)
old_requeue_request(rq);
else {
@ -1211,6 +1227,7 @@ static void dm_softirq_done(struct request *rq)
int rw;
if (!clone) {
rq_end_stats(tio->md, rq);
rw = rq_data_dir(rq);
if (!rq->q->mq_ops) {
blk_end_request_all(rq, tio->error);
@ -1943,6 +1960,14 @@ static void dm_start_request(struct mapped_device *md, struct request *orig)
md->last_rq_start_time = ktime_get();
}
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies;
tio->n_sectors = blk_rq_sectors(orig);
dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),
tio->n_sectors, false, 0, &tio->stats_aux);
}
/*
* Hold the md reference here for the in-flight I/O.
* We can't rely on the reference count by device opener,
@ -2689,6 +2714,7 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
/* Direct call is fine since .queue_rq allows allocations */
if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
/* Undo dm_start_request() before requeuing */
rq_end_stats(md, rq);
rq_completed(md, rq_data_dir(rq), false);
return BLK_MQ_RQ_QUEUE_BUSY;
}