[PATCH v9 2/6] block: loop: set QUEUE_FLAG_NOMERGES for request queue of loop

Ming Lei
2015-08-06T08:42:59Z

It doesn't make sense to enable merge because the I/O
submitted to backing file is handled page by page.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
drivers/block/loop.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f9889b6..eee7510 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1595,6 +1595,12 @@ static int loop_add(struct loop_device **l, int i)
}
lo->lo_queue->queuedata = lo;

+ /*
+ * It doesn't make sense to enable merge because the I/O
+ * submitted to backing file is handled page by page.
+ */
+ queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, lo->lo_queue);
+
INIT_LIST_HEAD(&lo->write_cmd_head);
INIT_WORK(&lo->write_work, loop_queue_write_work);

--
1.9.1