Commit 32f64cad authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block/mq-deadline: Add an invariant check 



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.

Reviewed-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: default avatarNiklas Cassel <Niklas.Cassel@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210927220328.1410161-3-bvanassche@acm.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e2c7275d

block/mq-deadline.c

+12 −6
Original line number Diff line number Diff line
@@ -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;