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-rw-r--r--block/cfq-iosched.c46
1 files changed, 25 insertions, 21 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b6491c0..f92ba2a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -532,6 +532,12 @@ static void cfq_add_rq_rb(struct request *rq)
if (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq);
+
+ /*
+ * check if this request is a better next-serve candidate
+ */
+ cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+ BUG_ON(!cfqq->next_rq);
}
static inline void
@@ -986,9 +992,9 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* expire an async queue immediately if it has used up its slice. idle
* queue always expire after 1 dispatch round.
*/
- if ((!cfq_cfqq_sync(cfqq) &&
+ if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq)) {
+ cfq_class_idle(cfqq))) {
cfqq->slice_end = jiffies + 1;
cfq_slice_expired(cfqd, 0, 0);
}
@@ -1051,19 +1057,21 @@ cfq_dispatch_requests(request_queue_t *q, int force)
while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
int max_dispatch;
- /*
- * Don't repeat dispatch from the previous queue.
- */
- if (prev_cfqq == cfqq)
- break;
+ if (cfqd->busy_queues > 1) {
+ /*
+ * Don't repeat dispatch from the previous queue.
+ */
+ if (prev_cfqq == cfqq)
+ break;
- /*
- * So we have dispatched before in this round, if the
- * next queue has idling enabled (must be sync), don't
- * allow it service until the previous have continued.
- */
- if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
- break;
+ /*
+ * So we have dispatched before in this round, if the
+ * next queue has idling enabled (must be sync), don't
+ * allow it service until the previous have continued.
+ */
+ if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
+ break;
+ }
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
@@ -1370,7 +1378,9 @@ retry:
atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;
- cfq_mark_cfqq_idle_window(cfqq);
+ if (key != CFQ_KEY_ASYNC)
+ cfq_mark_cfqq_idle_window(cfqq);
+
cfq_mark_cfqq_prio_changed(cfqq);
cfq_mark_cfqq_queue_new(cfqq);
cfq_init_prio_data(cfqq);
@@ -1635,12 +1645,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->meta_pending++;
/*
- * check if this request is a better next-serve candidate)) {
- */
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
- BUG_ON(!cfqq->next_rq);
-
- /*
* we never wait for an async request and we don't allow preemption
* of an async request. so just return early
*/
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