From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752205AbdFAQRr (ORCPT ); Thu, 1 Jun 2017 12:17:47 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33276 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752137AbdFAPo7 (ORCPT ); Thu, 1 Jun 2017 11:44:59 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "K. Y. Srinivasan" , "Greg Kroah-Hartman" , "Haiyang Zhang" , "Dexuan Cui" Date: Thu, 01 Jun 2017 16:43:15 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 021/212] hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Haiyang Zhang commit e1c0d82dab4a4605d3bd1968436f030dfed4a829 upstream. 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 Signed-off-by: Ben Hutchings --- drivers/hv/connection.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -418,6 +418,7 @@ int vmbus_post_msg(void *buffer, size_t 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; @@ -427,7 +428,7 @@ int vmbus_post_msg(void *buffer, size_t * 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) { @@ -450,7 +451,9 @@ int vmbus_post_msg(void *buffer, size_t } retries++; - msleep(1000); + msleep(msec); + if (msec < 2048) + msec *= 2; } return ret; }