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>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3df41a0..03b1e47 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -885,16 +885,17 @@
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;
}