From e1c0d82dab4a4605d3bd1968436f030dfed4a829 Mon Sep 17 00:00:00 2001 From: Haiyang Zhang Date: Fri, 27 Mar 2015 09:10:14 -0700 Subject: [PATCH] hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() 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 Reviewed-by: K. Y. Srinivasan Reviewed-by: Dexuan Cui Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/connection.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 583d7d42b46d..b27220a425f4 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; } -- 2.45.2