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

K. Y. Srinivasan
2012-12-01T14:23:44Z

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@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@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