[PATCH 14/18] drbd: explicitly submit meta data requests with REQ_NOIDLE

From: Philipp Reisner
Date: Mon Jun 30 2014 - 11:56:10 EST


From: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>

For some reason we have assumed NOIDLE was implied
by one of the other flags we set. It is not (anymore?).
Explicitly set REQ_NOIDLE for synchronous meta data updates,
or we can seriously starve random writes when using CFQ.

Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
---
drivers/block/drbd/drbd_actlog.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 278c31f..14b2f27 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -150,7 +150,7 @@ static int _drbd_md_sync_page_io(struct drbd_device *device,

if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
rw |= REQ_FUA | REQ_FLUSH;
- rw |= REQ_SYNC;
+ rw |= REQ_SYNC | REQ_NOIDLE;

bio = bio_alloc_drbd(GFP_NOIO);
bio->bi_bdev = bdev->md_bdev;
--
1.9.1

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