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block/mq-deadline: Add an invariant check

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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: 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/20210927220328.1410161-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2021-09-27 15:03:26 -07:00 committed by Jens Axboe
parent e2c7275dc0
commit 32f64cad97
1 changed files with 12 additions and 6 deletions
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18
block/mq-deadline.c
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@ -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;