On Mon, 2017-09-25 at 15:14 +0900, Damien Le Moal wrote:
> - return rq_entry_fifo(dd->fifo_list[data_dir].next);
> + if (!dd->zones_wlock || data_dir == READ)
> + return rq_entry_fifo(dd->fifo_list[data_dir].next);
> +
> + spin_lock_irqsave(&dd->zone_lock, flags);
> +
> + list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) {
> + if (deadline_can_dispatch_request(dd, rq))
> + goto out;
> + }
> + rq = NULL;
> +
> +out:
> + spin_unlock_irqrestore(&dd->zone_lock, flags);
Is it documented somewhere what dd->zone_lock protects and when that lock
should be
acquired?
> /*
> * This may be a requeue of a request that has locked its
> - * target zone. If this is the case, release the request zone lock.
> + * target zone. If this is the case, release the zone lock.
> */
> if (deadline_request_has_zone_wlock(rq))
> deadline_wunlock_zone(dd, rq);
Can this change be folded into the patch that introduced that comment?
> @@ -570,6 +621,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx,
> struct request *rq,
>
> blk_mq_sched_request_inserted(rq);
>
> + if (at_head && deadline_request_needs_zone_wlock(dd, rq))
> + pr_info("######## Write at head !\n");
> +
> if (at_head || blk_rq_is_passthrough(rq)) {
> if (at_head)
> list_add(&rq->queuelist, &dd->dispatch);
Will it be easy to users who analyze a kernel log to figure out why that
message has been generated? Should that message perhaps include the block
device name, zone number and request sector number?
Thanks,
Bart.
