Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753013AbaJ2BsW (ORCPT ); Tue, 28 Oct 2014 21:48:22 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:35021 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751619AbaJ2BsV (ORCPT ); Tue, 28 Oct 2014 21:48:21 -0400 Message-ID: <54504672.8010804@linux.vnet.ibm.com> Date: Wed, 29 Oct 2014 07:14:18 +0530 From: Preeti U Murthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Daniel Lezcano CC: "Rafael J. Wysocki" , Nicolas Pitre , "linux-pm@vger.kernel.org" , LKML , Peter Zijlstra , Lists linaro-kernel , patches@linaro.org Subject: Re: [PATCH V2 3/5] cpuidle: idle: menu: Don't reflect when a state selection failed References: <1414054881-17713-1-git-send-email-daniel.lezcano@linaro.org> <1414054881-17713-3-git-send-email-daniel.lezcano@linaro.org> <544FE032.5050900@linaro.org> In-Reply-To: <544FE032.5050900@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14102901-0029-0000-0000-000000F72FC6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/28/2014 11:58 PM, Daniel Lezcano wrote: > On 10/28/2014 08:01 AM, Preeti Murthy wrote: >> On Thu, Oct 23, 2014 at 2:31 PM, Daniel Lezcano >> wrote: >>> In the current code, the check to reflect or not the outcoming state >>> is done >>> against the idle state which has been chosen and its value. >>> >>> Instead of doing a check in each of the reflect functions, just don't >>> call reflect >>> if something went wrong in the idle path. >>> >>> Signed-off-by: Daniel Lezcano >>> Acked-by: Nicolas Pitre >>> --- >>> drivers/cpuidle/governors/ladder.c | 3 +-- >>> drivers/cpuidle/governors/menu.c | 4 +--- >>> kernel/sched/idle.c | 3 ++- >>> 3 files changed, 4 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/cpuidle/governors/ladder.c >>> b/drivers/cpuidle/governors/ladder.c >>> index fb396d6..c0b36a8 100644 >>> --- a/drivers/cpuidle/governors/ladder.c >>> +++ b/drivers/cpuidle/governors/ladder.c >>> @@ -165,8 +165,7 @@ static int ladder_enable_device(struct >>> cpuidle_driver *drv, >>> static void ladder_reflect(struct cpuidle_device *dev, int index) >>> { >>> struct ladder_device *ldev = &__get_cpu_var(ladder_devices); >>> - if (index > 0) >>> - ldev->last_state_idx = index; >>> + ldev->last_state_idx = index; >>> } >>> >>> static struct cpuidle_governor ladder_governor = { >>> diff --git a/drivers/cpuidle/governors/menu.c >>> b/drivers/cpuidle/governors/menu.c >>> index a17515f..3907301 100644 >>> --- a/drivers/cpuidle/governors/menu.c >>> +++ b/drivers/cpuidle/governors/menu.c >>> @@ -365,9 +365,7 @@ static int menu_select(struct cpuidle_driver >>> *drv, struct cpuidle_device *dev, >>> static void menu_reflect(struct cpuidle_device *dev, int index) >>> { >>> struct menu_device *data = &__get_cpu_var(menu_devices); >>> - data->last_state_idx = index; >>> - if (index >= 0) >>> - data->needs_update = 1; >>> + data->needs_update = 1; >> >> Why is the last_state_idx not getting updated ? > > Oups, right. This is missing. > > Thanks for pointing this out. > > By the way, I don't think a back end driver is changing the selected > state currently and I am not sure this is desirable since we want to > trust the state we are going (as a best effort). So if the 'enter' > function does not change the index, that means the last_state_idx has > not to be changed since it has been assigned in the 'select' function. Hmm Right. So you might want to remove the last_state_idx update in ladder_reflect() also? Regards Preeti U Murthy > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/