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-rw-r--r--block/cfq-iosched.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index cba8a5d91bf..56e9d8503cf 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