On Thu, Sep 23, 2021 at 04:26:53PM -0700, Bart Van Assche wrote:
> Check a statistics invariant at module unload time. When running
> blktests, the invariant is verified every time a request queue is
> removed and hence is verified at least once per test.
>
> 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 | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index b1175e4560ad..6deb4306bcf3 100644
> --- a/block/mq-deadline.c
> +++ b/block/mq-deadline.c
> @@ -270,6 +270,12 @@ deadline_move_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
> deadline_remove_request(rq->q, per_prio, rq);
> }
>
> +/* Number of requests queued for a given priority level. */
> +static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
> +{
> + return dd_sum(dd, inserted, prio) - dd_sum(dd, completed, prio);
> +}
> +
> /*
> * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
> * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
> @@ -539,6 +545,12 @@ static void dd_exit_sched(struct elevator_queue *e)
>
> WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ]));
> WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE]));
> + WARN_ONCE(dd_queued(dd, prio) != 0,
> + "statistics for priority %d: i %u m %u d %u c %u\n",
> + prio, dd_sum(dd, inserted, prio),
> + dd_sum(dd, merged, prio),
> + dd_sum(dd, dispatched, prio),
> + dd_sum(dd, completed, prio));
> }
>
> free_percpu(dd->stats);
> @@ -950,12 +962,6 @@ static int dd_async_depth_show(void *data, struct seq_file *m)
> return 0;
> }
>
> -/* Number of requests queued for a given priority level. */
> -static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
> -{
> - return dd_sum(dd, inserted, prio) - dd_sum(dd, completed, prio);
> -}
> -
> static int dd_queued_show(void *data, struct seq_file *m)
> {
> struct request_queue *q = data;
Reviewed-by: Niklas Cassel <niklas.cassel@xxxxxxx>
