1 files changed, 9 insertions, 2 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index cba8a5d91bfa..56e9d8503cf1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1903,10 +1903,17 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                  * Remember that we saw a request from this process, but
                  * don't start queuing just yet. Otherwise we risk seeing lots
                  * of tiny requests, because we disrupt the normal plugging
-                 * and merging.
+                 * and merging. If the request is already larger than a single
+                 * page, let it rip immediately. For that case we assume that
+                 * merging is already done.
                  */
-                if (cfq_cfqq_wait_request(cfqq))
+                if (cfq_cfqq_wait_request(cfqq)) {
+                        if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE) {
+                                del_timer(&cfqd->idle_slice_timer);
+                                blk_start_queueing(cfqd->queue);
+                        }
                         cfq_mark_cfqq_must_dispatch(cfqq);
+                }
         } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
                 /*
                  * not the active queue - expire current slice if it is