[PATCH 03/28] Drivers: hv: Turn off batched reading for util drivers

K. Y. Srinivasan kys at microsoft.com
Sat Dec 1 14:46:34 UTC 2012


Util driver is not a performance critical driver and furthermore some
util services such as KVP can only handle one outstanding message
from the host. Turn off batched reading for util drivers.

Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz at microsoft.com>
---
 drivers/hv/hv_util.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index a0667de..a62a760 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -274,6 +274,16 @@ static int util_probe(struct hv_device *dev,
 		}
 	}
 
+	/*
+	 * The set of services managed by the util driver are not performance
+	 * critical and do not need batched reading. Furthermore, some services
+	 * such as KVP can only handle one message from the host at a time.
+	 * Turn off batched reading for all util drivers before we open the
+	 * channel.
+	 */
+
+	set_channel_read_state(dev->channel, false);
+
 	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
 			srv->util_cb, dev->channel);
 	if (ret)
-- 
1.7.4.1




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