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<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 4eb1906cf6c6..8e0b86a9111a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -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);
 }