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Subject[PATCH] hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg()
Date
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 <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@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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