From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Anson Huang <anson.huang@nxp.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Peng Fan <peng.fan@nxp.com>, Jacky Bai <ping.bai@nxp.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: About CPU hot-plug stress test failed in cpufreq driver
Date: Tue, 10 Dec 2019 12:03:21 +0100 [thread overview]
Message-ID: <7300000.zMGgbreFFD@kreacher> (raw)
In-Reply-To: <20191210085744.ocdcpubkmac6mk3i@vireshk-i7>
On Tuesday, December 10, 2019 9:57:44 AM CET Viresh Kumar wrote:
> On 10-12-19, 09:50, Rafael J. Wysocki wrote:
> > Index: linux-pm/include/linux/cpufreq.h
> > ===================================================================
> > --- linux-pm.orig/include/linux/cpufreq.h
> > +++ linux-pm/include/linux/cpufreq.h
> > @@ -599,11 +599,13 @@ static inline bool cpufreq_this_cpu_can_
> > {
> > /*
> > * Allow remote callbacks if:
> > - * - dvfs_possible_from_any_cpu flag is set
> > * - the local and remote CPUs share cpufreq policy
> > + * - dvfs_possible_from_any_cpu flag is set and the CPU running the
> > + * code is not going offline.
> > */
> > - return policy->dvfs_possible_from_any_cpu ||
> > - cpumask_test_cpu(smp_processor_id(), policy->cpus);
> > + return cpumask_test_cpu(smp_processor_id(), policy->cpus) ||
> > + (policy->dvfs_possible_from_any_cpu &&
> > + !cpumask_test_cpu(smp_processor_id(), policy->related_cpus));
>
> This isn't enough as you are assuming that only a CPU from policy->related_cpus
> can do remote processing. On a ARM platform (like Qcom's Krait, octa-core), all
> 8 CPUs have separate policies as they don't share clock lines. Though they can
> still do remote processing for each other as the clk registers are common.
>
> Also policy->related_cpus can anyway update frequency for the policy even if
> dvfs_possible_from_any_cpu is set to false.
I know, see
https://lore.kernel.org/linux-pm/CAJZ5v0h0934-VBODZZJ8gEG2byuhQ+bomoCuTmmQZOBtqu5bKQ@mail.gmail.com/T/#mccadfdc557468072ab6c5525601a71d60070e99b
next prev parent reply other threads:[~2019-12-10 11:03 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <DB3PR0402MB391626A8ECFDC182C6EDCF8DF54E0@DB3PR0402MB3916.eurprd04.prod.outlook.com>
2019-11-21 9:35 ` About CPU hot-plug stress test failed in cpufreq driver Viresh Kumar
2019-11-21 10:13 ` Anson Huang
2019-11-21 10:53 ` Rafael J. Wysocki
2019-11-21 10:56 ` Rafael J. Wysocki
2019-11-22 5:15 ` Anson Huang
2019-11-22 9:59 ` Rafael J. Wysocki
2019-11-25 6:05 ` Anson Huang
2019-11-25 9:43 ` Anson Huang
2019-11-26 6:18 ` Viresh Kumar
2019-11-26 8:22 ` Anson Huang
2019-11-26 8:25 ` Viresh Kumar
2019-11-25 12:44 ` Rafael J. Wysocki
2019-11-26 8:57 ` Rafael J. Wysocki
2019-11-29 11:39 ` Rafael J. Wysocki
2019-11-29 13:44 ` Anson Huang
2019-12-05 8:53 ` Anson Huang
2019-12-05 10:48 ` Rafael J. Wysocki
2019-12-05 13:18 ` Anson Huang
2019-12-05 15:52 ` Rafael J. Wysocki
2019-12-09 10:31 ` Peng Fan
2019-12-09 10:37 ` Anson Huang
2019-12-09 10:56 ` Anson Huang
2019-12-09 11:23 ` Rafael J. Wysocki
2019-12-09 12:32 ` Anson Huang
2019-12-09 12:44 ` Rafael J. Wysocki
2019-12-09 14:18 ` Anson Huang
2019-12-10 5:39 ` Anson Huang
2019-12-10 5:53 ` Peng Fan
2019-12-10 7:05 ` Viresh Kumar
2019-12-10 8:22 ` Rafael J. Wysocki
2019-12-10 8:29 ` Anson Huang
2019-12-10 8:36 ` Viresh Kumar
2019-12-10 8:37 ` Peng Fan
2019-12-10 8:37 ` Rafael J. Wysocki
2019-12-10 8:43 ` Peng Fan
2019-12-10 8:45 ` Anson Huang
2019-12-10 8:50 ` Rafael J. Wysocki
2019-12-10 8:51 ` Anson Huang
2019-12-10 10:39 ` Rafael J. Wysocki
2019-12-10 10:54 ` Rafael J. Wysocki
2019-12-11 5:08 ` Anson Huang
2019-12-11 8:59 ` Peng Fan
2019-12-11 9:36 ` Rafael J. Wysocki
2019-12-11 9:43 ` Peng Fan
2019-12-11 9:52 ` Rafael J. Wysocki
2019-12-11 10:11 ` Peng Fan
2019-12-10 10:54 ` Viresh Kumar
2019-12-10 11:07 ` Rafael J. Wysocki
2019-12-10 8:57 ` Viresh Kumar
2019-12-10 11:03 ` Rafael J. Wysocki [this message]
2019-12-10 9:04 ` Rafael J. Wysocki
2019-12-10 8:31 ` Viresh Kumar
2019-12-10 8:12 ` Rafael J. Wysocki
2019-12-05 11:00 ` Viresh Kumar
2019-12-05 11:10 ` Rafael J. Wysocki
2019-12-05 11:17 ` Viresh Kumar
2019-11-21 10:37 ` Rafael J. Wysocki
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