block: change the request allocation/congestion logic to be sync/async based
This makes sure that we never wait on async IO for sync requests, instead
of doing the split on writes vs reads.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/block/elevator.c b/block/elevator.c
index 98259ed..ca6788a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -677,7 +677,7 @@
}
if (unplug_it && blk_queue_plugged(q)) {
- int nrq = q->rq.count[READ] + q->rq.count[WRITE]
+ int nrq = q->rq.count[BLK_RW_SYNC] + q->rq.count[BLK_RW_ASYNC]
- q->in_flight;
if (nrq >= q->unplug_thresh)