From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [PATCH v2] cpufreq: schedutil: Examine the correct CPU when we update util Date: Thu, 2 Nov 2017 17:10:48 +0530 Message-ID: <20171102114048.GC4240@vireshk-i7> References: <20171102111022.GB4240@vireshk-i7> <20171102113840.17439-1-chris.redpath@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pg0-f68.google.com ([74.125.83.68]:53868 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751503AbdKBLkx (ORCPT ); Thu, 2 Nov 2017 07:40:53 -0400 Received: by mail-pg0-f68.google.com with SMTP id s2so4843045pge.10 for ; Thu, 02 Nov 2017 04:40:52 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20171102113840.17439-1-chris.redpath@arm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Chris Redpath Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Morten Rasmussen , Dietmar Eggemann , "Rafael J . Wysocki" , Ingo Molnar , Peter Zijlstra On 02-11-17, 11:38, Chris Redpath wrote: > Since: > 4296f23ed cpufreq: schedutil: Fix per-CPU structure initialization in > sugov_start() This is still incorrect. This BUG has nothing to do with 4296f23ed AFAICT. > We lost the value of sg_cpu->cpu which is assigned during > sugov_register. The memset in sugov_start overwrites it with zero. > > The change here was triggered by the commit adding the remote update > functionality. > 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks") > > This leads to always looking at the utilization of CPU0 instead of > the one we just updated when we do a utilization update callback. > > Let's fix this by consolidating the initialization code into > sugov_start(). > > Fixes: 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks") > Signed-off-by: Chris Redpath > Reviewed-by: Patrick Bellasi > Reviewed-by: Brendan Jackman > Cc: Rafael J. Wysocki > Cc: Viresh Kumar > Cc: Ingo Molnar > Cc: Peter Zijlstra > --- > kernel/sched/cpufreq_schedutil.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 6c1a7fcfa2a7..dc68a1ccdb33 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -728,6 +728,7 @@ static int sugov_start(struct cpufreq_policy *policy) > struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); > > memset(sg_cpu, 0, sizeof(*sg_cpu)); > + sg_cpu->cpu = cpu; > sg_cpu->sg_policy = sg_policy; > sg_cpu->flags = SCHED_CPUFREQ_RT; > sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq; > @@ -793,11 +794,6 @@ struct cpufreq_governor *cpufreq_default_governor(void) > > static int __init sugov_register(void) > { > - int cpu; > - > - for_each_possible_cpu(cpu) > - per_cpu(sugov_cpu, cpu).cpu = cpu; > - > return cpufreq_register_governor(&schedutil_gov); > } > fs_initcall(sugov_register); > -- > 2.13.1.449.g02a2850 -- viresh