From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752065AbbCYVtZ (ORCPT ); Wed, 25 Mar 2015 17:49:25 -0400 Received: from p3plsmtps2ded02.prod.phx3.secureserver.net ([208.109.80.59]:53657 "EHLO p3plsmtps2ded02.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750764AbbCYVtY (ORCPT ); Wed, 25 Mar 2015 17:49:24 -0400 X-Greylist: delayed 451 seconds by postgrey-1.27 at vger.kernel.org; Wed, 25 Mar 2015 17:49:24 EDT x-originating-ip: 72.167.245.219 From: Haiyang Zhang To: kys@microsoft.com Cc: haiyangz@microsoft.com, olaf@aepfle.de, jasowang@redhat.com, linux-kernel@vger.kernel.org, driverdev-devel@linuxdriverproject.org Subject: [PATCH] hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() Date: Wed, 25 Mar 2015 15:58:39 -0700 Message-Id: <1427324319-14211-1-git-send-email-haiyangz@microsoft.com> X-Mailer: git-send-email 1.7.4.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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