Re: [PATCH RESEND] block/mq-deadline: adjust the timeout period of the per_prio->dispatch

[Jens Axboe]

On 9/25/25 8:38 PM, chengkaitao wrote:
> From: chengkaitao <chengkaitao@xxxxxxxxxx>
> 
> Reference function started_after()
> Before modification:
> 	Timeout for dispatch{read}: 9.5s
> 	started_after - 0.5s < latest_start - 10s
> 	9.5s < latest_start - started_after
> 
> 	Timeout for dispatch{write}: 5s
> 	started_after - 5s < latest_start - 10s
> 	5s < latest_start - started_after
> 
> At this point, write requests have higher priority than read requests.
> 
> After modification:
> 	Timeout for dispatch{read/write}: 5s
> 	prio_aging_expire / 2 < latest_start - started_after
> 
> Signed-off-by: chengkaitao <chengkaitao@xxxxxxxxxx>
> ---
>  block/mq-deadline.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index b9b7cdf1d3c9..f311168f8dfe 100644
> --- a/block/mq-deadline.c
> +++ b/block/mq-deadline.c
> @@ -672,7 +672,8 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
>  
>  	if (flags & BLK_MQ_INSERT_AT_HEAD) {
>  		list_add(&rq->queuelist, &per_prio->dispatch);
> -		rq->fifo_time = jiffies;
> +		rq->fifo_time = jiffies + dd->fifo_expire[data_dir]
> +				- dd->prio_aging_expire / 2;
>  	} else {
>  		deadline_add_rq_rb(per_prio, rq);
>  

Adding Damien as he's worked on mq-deadline the most recently.

-- 
Jens Axboe