cfq-iosched: tweak the FIFO checking

We currently check the FIFO once per slice. Optimize that a bit and
only do it as the first thing for a new slice, so we don't end up
doing a single request and then seek to the FIFO requests.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2007-01-19 12:01:16 +11:00 committed by Jens Axboe
parent 1792669cc1
commit cb8874119e

View file

@ -885,16 +885,17 @@ static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
cfq_mark_cfqq_fifo_expire(cfqq);
if (list_empty(&cfqq->fifo))
return NULL;
fifo = cfq_cfqq_class_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next);
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
cfq_mark_cfqq_fifo_expire(cfqq);
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
return rq;
}
return NULL;
}