block/mq-deadline: Improve request accounting further

The scheduler .insert_requests() callback is called when a request is
queued for the first time and also when it is requeued. Only count a
request the first time it is queued. Additionally, since the mq-deadline
scheduler only performs zone locking for requests that have been
inserted, skip the zone unlock code for requests that have not been
inserted into the mq-deadline scheduler.

Fixes: 38ba64d12d4c ("block/mq-deadline: Track I/O statistics")
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Niklas Cassel <Niklas.Cassel@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210927220328.1410161-2-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 47f042f..c27b434 100644 (file)
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -677,8 +677,10 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
        blk_req_zone_write_unlock(rq);
 
        prio = ioprio_class_to_prio[ioprio_class];
-       dd_count(dd, inserted, prio);
-       rq->elv.priv[0] = (void *)(uintptr_t)1;
+       if (!rq->elv.priv[0]) {
+               dd_count(dd, inserted, prio);
+               rq->elv.priv[0] = (void *)(uintptr_t)1;
+       }
 
        if (blk_mq_sched_try_insert_merge(q, rq, &free)) {
                blk_mq_free_requests(&free);
@@ -759,12 +761,13 @@ static void dd_finish_request(struct request *rq)
 
        /*
         * The block layer core may call dd_finish_request() without having
-        * called dd_insert_requests(). Hence only update statistics for
-        * requests for which dd_insert_requests() has been called. See also
-        * blk_mq_request_bypass_insert().
+        * called dd_insert_requests(). Skip requests that bypassed I/O
+        * scheduling. See also blk_mq_request_bypass_insert().
         */
-       if (rq->elv.priv[0])
-               dd_count(dd, completed, prio);
+       if (!rq->elv.priv[0])
+               return;
+
+       dd_count(dd, completed, prio);
 
        if (blk_queue_is_zoned(q)) {
                unsigned long flags;