On 2021/09/24 8:27, Bart Van Assche wrote:
> 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")
> Cc: Damien Le Moal <damien.lemoal@xxxxxxx>
> Cc: Niklas Cassel <Niklas.Cassel@xxxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> block/mq-deadline.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index 7f3c3932b723..b1175e4560ad 100644
> --- 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;
>
Looks good to me.
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
