cfq-iosched: tighten queue request overlap condition

For tagged devices, allow overlap of requests if the idle window
isn't enabled on the current active queue.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a8237be..e859b49 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -989,7 +989,8 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
         * flight or is idling for a new request, allow either of these
         * conditions to happen (or time out) before selecting a new queue.
         */
-       if (cfqq->dispatched || timer_pending(&cfqd->idle_slice_timer)) {
+       if (timer_pending(&cfqd->idle_slice_timer) ||
+           (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
                cfqq = NULL;
                goto keep_queue;
        }