From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163042Ab1FAIet (ORCPT ); Wed, 1 Jun 2011 04:34:49 -0400 Received: from cantor.suse.de ([195.135.220.2]:45138 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1163069Ab1FAI1Y (ORCPT ); Wed, 1 Jun 2011 04:27:24 -0400 X-Mailbox-Line: From linux@blue.kroah.org Wed Jun 1 17:12:14 2011 Message-Id: <20110601081213.404044588@blue.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 01 Jun 2011 17:11:48 +0900 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Tero Kristo , Len Brown , Greg Kroah-Hartman Subject: [138/165] cpuidle: menu: fixed wrapping timers at 4.294 seconds In-Reply-To: <20110601081349.GA10017@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.39-stable review patch. If anyone has any objections, please let us know. ------------------ Content-Length: 1325 Lines: 40 From: Tero Kristo commit 7467571f4480b273007517b26297c07154c73924 upstream. Cpuidle menu governor is using u32 as a temporary datatype for storing nanosecond values which wrap around at 4.294 seconds. This causes errors in predicted sleep times resulting in higher than should be C state selection and increased power consumption. This also breaks cpuidle state residency statistics. Signed-off-by: Tero Kristo Signed-off-by: Len Brown Signed-off-by: Greg Kroah-Hartman --- drivers/cpuidle/governors/menu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_de unsigned int power_usage = -1; int i; int multiplier; + struct timespec t; if (data->needs_update) { menu_update(dev); @@ -251,8 +252,9 @@ static int menu_select(struct cpuidle_de return 0; /* determine the expected residency time, round up */ + t = ktime_to_timespec(tick_nohz_get_sleep_length()); data->expected_us = - DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000); + t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC; data->bucket = which_bucket(data->expected_us);