Most of the retries can be done within a millisecond successfully, so we
sleep 1ms before the first retry, then gradually increase the retry
interval to 2^n with max value of 2048ms. Doing so, we will have shorter
overall delay time, because most of the cases succeed within 1-2 attempts.

Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
Reviewed-by: K. Y. Srinivasan <k...@microsoft.com>
---
 drivers/hv/connection.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 583d7d4..b27220a 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -422,6 +422,7 @@ int vmbus_post_msg(void *buffer, size_t buflen)
        union hv_connection_id conn_id;
        int ret = 0;
        int retries = 0;
+       u32 msec = 1;
 
        conn_id.asu32 = 0;
        conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
@@ -431,7 +432,7 @@ int vmbus_post_msg(void *buffer, size_t buflen)
         * insufficient resources. Retry the operation a couple of
         * times before giving up.
         */
-       while (retries < 10) {
+       while (retries < 20) {
                ret = hv_post_message(conn_id, 1, buffer, buflen);
 
                switch (ret) {
@@ -454,7 +455,9 @@ int vmbus_post_msg(void *buffer, size_t buflen)
                }
 
                retries++;
-               msleep(1000);
+               msleep(msec);
+               if (msec < 2048)
+                       msec *= 2;
        }
        return ret;
 }
-- 
1.7.4.1

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