From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763476AbZE0MzN (ORCPT ); Wed, 27 May 2009 08:55:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762367AbZE0MzA (ORCPT ); Wed, 27 May 2009 08:55:00 -0400 Received: from hera.kernel.org ([140.211.167.34]:51214 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759354AbZE0My5 (ORCPT ); Wed, 27 May 2009 08:54:57 -0400 Date: Wed, 27 May 2009 12:54:31 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: cf1240033cc81216a18eec0ca71466f7fe4eeda8 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 12:54:32 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: cf1240033cc81216a18eec0ca71466f7fe4eeda8 Gitweb: http://git.kernel.org/tip/cf1240033cc81216a18eec0ca71466f7fe4eeda8 Author: Eero Nurkkala AuthorDate: Mon, 25 May 2009 09:57:37 +0300 Committer: Thomas Gleixner CommitDate: Wed, 27 May 2009 14:51:47 +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. 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, 9 insertions(+), 3 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d3f1ef4..233b4e7 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -222,6 +222,15 @@ void tick_nohz_stop_sched_tick(int inidle) cpu = smp_processor_id(); ts = &per_cpu(tick_cpu_sched, cpu); + + /* + * 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; + now = tick_nohz_start_idle(ts); /* @@ -239,9 +248,6 @@ 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())