From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756953Ab1FPHLG (ORCPT ); Thu, 16 Jun 2011 03:11:06 -0400 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:33374 "EHLO out4.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756878Ab1FPHK4 (ORCPT ); Thu, 16 Jun 2011 03:10:56 -0400 X-Sasl-enc: zwqP1ZKn6/JPKGIL/Pv5Xenq8B5nvpvN9S1UMDrb2zKE 1308208255 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Jun 15 17:29:07 2011 Message-Id: <20110616002907.725386806@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 15 Jun 2011 17:28:35 -0700 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 Subject: [39/85] cpuidle: menu: fixed wrapping timers at 4.294 seconds In-Reply-To: <20110616002917.GA3627@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-longterm review patch. If anyone has any objections, please let us know. ------------------ 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 @@ -185,6 +185,7 @@ static int menu_select(struct cpuidle_de int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY); int i; int multiplier; + struct timespec t; if (data->needs_update) { menu_update(dev); @@ -199,8 +200,9 @@ 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);