On 11/16/21 11:25 PM, Christoph Hellwig wrote:
>> @@ -2208,6 +2208,19 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule)
>> int queued = 0;
>> int errors = 0;
>>
>> + /*
>> + * Peek first request and see if we have a ->queue_rqs() hook. If we
>> + * do, we can dispatch the whole plug list in one go. We already know
>> + * at this point that all requests belong to the same queue, caller
>> + * must ensure that's the case.
>> + */
>> + rq = rq_list_peek(&plug->mq_list);
>> + if (rq->q->mq_ops->queue_rqs) {
>> + rq->q->mq_ops->queue_rqs(&plug->mq_list);
>> + if (rq_list_empty(plug->mq_list))
>> + return;
>> + }
>
> I'd move this straight into the caller to simplify the follow, something
> like the patch below. Also I wonder if the slow path might want to
> be moved from blk_mq_flush_plug_list into a separate helper to keep
> the fast path as straight as possible?
Yes, I think that's better. I'll fold that in.
--
Jens Axboe
