From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FD1FC433EF for ; Tue, 26 Oct 2021 16:51:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB62F6108B for ; Tue, 26 Oct 2021 16:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236240AbhJZQxW (ORCPT ); Tue, 26 Oct 2021 12:53:22 -0400 Received: from foss.arm.com ([217.140.110.172]:34910 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232410AbhJZQxP (ORCPT ); Tue, 26 Oct 2021 12:53:15 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0DB061FB; Tue, 26 Oct 2021 09:50:50 -0700 (PDT) Received: from [192.168.185.184] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 34BA03F70D; Tue, 26 Oct 2021 09:50:44 -0700 (PDT) Subject: Re: [PATCH v2 1/5] arch_topology: Introduce thermal pressure update function To: Lukasz Luba , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, linux@armlinux.org.uk, gregkh@linuxfoundation.org, rafael@kernel.org, viresh.kumar@linaro.org, amitk@kernel.org, daniel.lezcano@linaro.org, amit.kachhap@gmail.com, thara.gopinath@linaro.org, bjorn.andersson@linaro.org, agross@kernel.org References: <20211015144550.23719-1-lukasz.luba@arm.com> <20211015144550.23719-2-lukasz.luba@arm.com> From: Dietmar Eggemann Message-ID: <431230a5-00e9-0211-0731-035eab5fa3f6@arm.com> Date: Tue, 26 Oct 2021 18:51:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211015144550.23719-2-lukasz.luba@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 15/10/2021 16:45, Lukasz Luba wrote: > The thermal pressure is a mechanism which is used for providing > information about reduced CPU performance to the scheduler. Usually code > has to convert the value from frequency units into capacity units, > which are understandable by the scheduler. Create a common conversion code > which can be just used via a handy API. > > Signed-off-by: Lukasz Luba > --- > arch/arm/include/asm/topology.h | 1 + > arch/arm64/include/asm/topology.h | 1 + > drivers/base/arch_topology.c | 36 ++++++++++++++++++++++++++++++- > include/linux/arch_topology.h | 3 +++ > include/linux/sched/topology.h | 7 ++++++ > 5 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h > index 470299ee2fba..aee6c456c085 100644 > --- a/arch/arm/include/asm/topology.h > +++ b/arch/arm/include/asm/topology.h > @@ -24,6 +24,7 @@ > /* Replace task scheduler's default thermal pressure API */ > #define arch_scale_thermal_pressure topology_get_thermal_pressure > #define arch_set_thermal_pressure topology_set_thermal_pressure > +#define arch_thermal_pressure_update topology_thermal_pressure_update > > #else > > diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h > index ec2db3419c41..c997015402bc 100644 > --- a/arch/arm64/include/asm/topology.h > +++ b/arch/arm64/include/asm/topology.h > @@ -33,6 +33,7 @@ void update_freq_counters_refs(void); > /* Replace task scheduler's default thermal pressure API */ > #define arch_scale_thermal_pressure topology_get_thermal_pressure > #define arch_set_thermal_pressure topology_set_thermal_pressure > +#define arch_thermal_pressure_update topology_thermal_pressure_update s/thermal_pressure_update/update_thermal_pressure ? The scheme seems to be {arch|topology}_*foo*_thermal_pressure But ... > > #include > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index 43407665918f..1fa28b5afdb2 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -25,6 +25,7 @@ > static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); > static struct cpumask scale_freq_counters_mask; > static bool scale_freq_invariant; > +static DEFINE_PER_CPU(u32, freq_factor) = 1; > > static bool supports_scale_freq_counters(const struct cpumask *cpus) > { > @@ -168,6 +169,40 @@ void topology_set_thermal_pressure(const struct cpumask *cpus, > } > EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); > > +/** > + * topology_thermal_pressure_update() - Update thermal pressure for CPUs > + * @cpus : The related CPUs for which capacity has been reduced > + * @capped_freq : The maximum allowed frequency that CPUs can run at > + * > + * Update the value of thermal pressure for all @cpus in the mask. The > + * cpumask should include all (online+offline) affected CPUs, to avoid > + * operating on stale data when hot-plug is used for some CPUs. The > + * @capped_freq must be less or equal to the max possible frequency and > + * reflects the currently allowed max CPUs frequency due to thermal capping. > + * The @capped_freq must be provided in kHz. > + */ > +void topology_thermal_pressure_update(const struct cpumask *cpus, > + unsigned long capped_freq) > +{ ... why not just s/unsigned long th_pressure/unsigned long capped_freq in existing topology_set_thermal_pressure() and move code the frequency/capacity conversion in there? The patch set will become considerably smaller. void topology_set_thermal_pressure(const struct cpumask *cpus, - unsigned long th_pressure) + unsigned long capped_freq) { + unsigned long max_capacity, capacity; int cpu; - for_each_cpu(cpu, cpus) - WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); + if (!cpus) + return; + + cpu = cpumask_first(cpus); + max_capacity = arch_scale_cpu_capacity(cpu); + + /* Convert to MHz scale which is used in 'freq_factor' */ + capped_freq /= 1000; + + capacity = mult_frac(capped_freq, max_capacity, + per_cpu(freq_factor, cpu)); + + for_each_cpu(cpu, cpus) { + WRITE_ONCE(per_cpu(thermal_pressure, cpu), + max_capacity - capacity); + } } EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); And a user like [drivers/thermal/cpufreq_cooling.c] can call arch_set_thermal_pressure(cpus, frequency). [...]