blkio: Add io_queued and avg_queue_size stats

These stats are useful for getting a feel for the queue depth of the cgroup,
i.e., how filled up its queues are at a given instant and over the existence of
the cgroup. This ability is useful when debugging problems in the wild as it
helps understand the application's IO pattern w/o having to read through the
userspace code (coz its tedious or just not available) or w/o the ability
to run blktrace (since you may not have root access and/or not want to disturb
performance).

Signed-off-by: Divyesh Shah<[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
This commit is contained in:
Divyesh Shah 2010-04-08 21:15:10 -07:00 • committed by Jens Axboe
commit cdc1184cf4
4 changed files with 134 additions and 6 deletions

View file

@ -1380,7 +1380,12 @@ static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
{
elv_rb_del(&cfqq->sort_list, rq);
cfqq->queued[rq_is_sync(rq)]--;
blkiocg_update_request_remove_stats(&cfqq->cfqg->blkg, rq_data_dir(rq),
rq_is_sync(rq));
cfq_add_rq_rb(rq);
blkiocg_update_request_add_stats(
&cfqq->cfqg->blkg, &cfqq->cfqd->serving_group->blkg,
rq_data_dir(rq), rq_is_sync(rq));
}
static struct request *
@ -1436,6 +1441,8 @@ static void cfq_remove_request(struct request *rq)
cfq_del_rq_rb(rq);
cfqq->cfqd->rq_queued--;
blkiocg_update_request_remove_stats(&cfqq->cfqg->blkg, rq_data_dir(rq),
rq_is_sync(rq));
if (rq_is_meta(rq)) {
WARN_ON(!cfqq->meta_pending);
cfqq->meta_pending--;
@ -1527,6 +1534,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
if (cfqq) {
cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",
cfqd->serving_prio, cfqd->serving_type);
blkiocg_update_set_active_queue_stats(&cfqq->cfqg->blkg);
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
cfqq->allocated_slice = 0;
@ -3213,6 +3221,9 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
list_add_tail(&rq->queuelist, &cfqq->fifo);
cfq_add_rq_rb(rq);
blkiocg_update_request_add_stats(&cfqq->cfqg->blkg,
&cfqd->serving_group->blkg, rq_data_dir(rq),
rq_is_sync(rq));
cfq_rq_enqueued(cfqd, cfqq, rq);
}