[PATCH 3/3] blk-throttle: add throttled io/bytes counter

[Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>]

Add another 2 interfaces to stat io throttle information:
  blkio.throttle.total_io_queued
  blkio.throttle.total_bytes_queued

These interfaces are used for monitoring throttled io/bytes and
analyzing if delay has relations with io throttle.

Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
---
 block/blk-throttle.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 1db461c..acc9feb 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -183,6 +183,10 @@ struct throtl_grp {
 	struct blkg_rwstat wait_time;
 	/* total IOs completed */
 	struct blkg_rwstat completed;
+	/* total bytes throttled */
+	struct blkg_rwstat total_bytes_queued;
+	/* total IOs throttled */
+	struct blkg_rwstat total_io_queued;
 };
 
 /* We measure latency for request size from <= 4k to >= 1M */
@@ -496,7 +500,9 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
 
 	if (blkg_rwstat_init(&tg->service_time, gfp) ||
 	    blkg_rwstat_init(&tg->wait_time, gfp) ||
-	    blkg_rwstat_init(&tg->completed, gfp))
+	    blkg_rwstat_init(&tg->completed, gfp) ||
+	    blkg_rwstat_init(&tg->total_bytes_queued, gfp) ||
+	    blkg_rwstat_init(&tg->total_io_queued, gfp))
 		goto err;
 
 	throtl_service_queue_init(&tg->service_queue);
@@ -528,6 +534,8 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
 	blkg_rwstat_exit(&tg->service_time);
 	blkg_rwstat_exit(&tg->wait_time);
 	blkg_rwstat_exit(&tg->completed);
+	blkg_rwstat_exit(&tg->total_bytes_queued);
+	blkg_rwstat_exit(&tg->total_io_queued);
 	kfree(tg);
 	return NULL;
 }
@@ -630,6 +638,10 @@ static void throtl_pd_offline(struct blkg_policy_data *pd)
 				    &tg->wait_time);
 		blkg_rwstat_add_aux(&blkg_to_tg(parent)->completed,
 				    &tg->completed);
+		blkg_rwstat_add_aux(&blkg_to_tg(parent)->total_bytes_queued,
+				    &tg->total_bytes_queued);
+		blkg_rwstat_add_aux(&blkg_to_tg(parent)->total_io_queued,
+				    &tg->total_io_queued);
 	}
 }
 
@@ -641,6 +653,8 @@ static void throtl_pd_free(struct blkg_policy_data *pd)
 	blkg_rwstat_exit(&tg->service_time);
 	blkg_rwstat_exit(&tg->wait_time);
 	blkg_rwstat_exit(&tg->completed);
+	blkg_rwstat_reset(&tg->total_bytes_queued);
+	blkg_rwstat_reset(&tg->total_io_queued);
 	kfree(tg);
 }
 
@@ -651,6 +665,8 @@ static void throtl_pd_reset(struct blkg_policy_data *pd)
 	blkg_rwstat_reset(&tg->service_time);
 	blkg_rwstat_reset(&tg->wait_time);
 	blkg_rwstat_reset(&tg->completed);
+	blkg_rwstat_reset(&tg->total_bytes_queued);
+	blkg_rwstat_reset(&tg->total_io_queued);
 }
 
 static struct throtl_grp *
@@ -1170,6 +1186,9 @@ static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn,
 	throtl_qnode_add_bio(bio, qn, &sq->queued[rw]);
 
 	sq->nr_queued[rw]++;
+	blkg_rwstat_add(&tg->total_bytes_queued, bio_op(bio),
+			throtl_bio_data_size(bio));
+	blkg_rwstat_add(&tg->total_io_queued, bio_op(bio), 1);
 	throtl_enqueue_tg(tg);
 }
 
@@ -1641,6 +1660,16 @@ static int tg_print_rwstat(struct seq_file *sf, void *v)
 		.private = offsetof(struct throtl_grp, completed),
 		.seq_show = tg_print_rwstat,
 	},
+	{
+		.name = "throttle.total_bytes_queued",
+		.private = offsetof(struct throtl_grp, total_bytes_queued),
+		.seq_show = tg_print_rwstat,
+	},
+	{
+		.name = "throttle.total_io_queued",
+		.private = offsetof(struct throtl_grp, total_io_queued),
+		.seq_show = tg_print_rwstat,
+	},
 	{ }	/* terminate */
 };
 
-- 
1.8.3.1