From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762583AbZE0L6U (ORCPT ); Wed, 27 May 2009 07:58:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760739AbZE0L6H (ORCPT ); Wed, 27 May 2009 07:58:07 -0400 Received: from hera.kernel.org ([140.211.167.34]:35058 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758258AbZE0L6E (ORCPT ); Wed, 27 May 2009 07:58:04 -0400 Date: Wed, 27 May 2009 11:57:33 GMT From: tip-bot for Eero Nurkkala To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, venkatesh.pallipadi@intel.com, riel@redhat.com, tero.kristo@nokia.com, ext-eero.nurkkala@nokia.com, tglx@linutronix.de Reply-To: riel@redhat.com, mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tero.kristo@nokia.com, ext-eero.nurkkala@nokia.com, venkatesh.pallipadi@intel.com, tglx@linutronix.de In-Reply-To: <12432346571351-git-send-email-ext-eero.nurkkala@nokia.com> References: <12432346571351-git-send-email-ext-eero.nurkkala@nokia.com> Subject: [tip:timers/urgent] NOHZ: Properly feed cpufreq ondemand governor Message-ID: Git-Commit-ID: 4e67ac87c460a3c876019fa05149591122ec5287 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Wed, 27 May 2009 11:57:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 4e67ac87c460a3c876019fa05149591122ec5287 Gitweb: http://git.kernel.org/tip/4e67ac87c460a3c876019fa05149591122ec5287 Author: Eero Nurkkala AuthorDate: Mon, 25 May 2009 09:57:37 +0300 Committer: Thomas Gleixner CommitDate: Wed, 27 May 2009 13:55:00 +0200 NOHZ: Properly feed cpufreq ondemand governor A call from irq_exit() may occasionally pause the timing info for cpufreq ondemand governor. This results in the cpufreq ondemand governor to fail to calculate the system load properly. Thus, relocate the checks for this particular case to keep the governor always functional. [ tglx: moved the check to the top of the function ] Signed-off-by: Eero Nurkkala Reported-by: Tero Kristo Acked-by: Rik van Riel Acked-by: Venkatesh Pallipadi LKML-Reference: <12432346571351-git-send-email-ext-eero.nurkkala@nokia.com> Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d3f1ef4..d3d6f3f 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -218,8 +218,15 @@ void tick_nohz_stop_sched_tick(int inidle) struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; int cpu; - local_irq_save(flags); + /* + * Call to tick_nohz_start_idle stops the last_update_time from being + * updated. Thus, it must not be called in the event we are called from + * irq_exit() with the prior state different than idle. + */ + if (!inidle && !ts->inidle) + return; + local_irq_save(flags); cpu = smp_processor_id(); ts = &per_cpu(tick_cpu_sched, cpu); now = tick_nohz_start_idle(ts); @@ -239,9 +246,6 @@ void tick_nohz_stop_sched_tick(int inidle) if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) goto end; - if (!inidle && !ts->inidle) - goto end; - ts->inidle = 1; if (need_resched())