From patchwork Wed Jul 1 09:07:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ionela Voinescu X-Patchwork-Id: 11635857 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D625A618 for ; Wed, 1 Jul 2020 09:10:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7634207C4 for ; Wed, 1 Jul 2020 09:10:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729463AbgGAJJn (ORCPT ); Wed, 1 Jul 2020 05:09:43 -0400 Received: from foss.arm.com ([217.140.110.172]:47844 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726255AbgGAJJl (ORCPT ); Wed, 1 Jul 2020 05:09:41 -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 071C61396; Wed, 1 Jul 2020 02:09:41 -0700 (PDT) Received: from e108754-lin.cambridge.arm.com (unknown [10.1.198.53]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 42E793F68F; Wed, 1 Jul 2020 02:09:39 -0700 (PDT) From: Ionela Voinescu To: rjw@rjwysocki.net, viresh.kumar@linaro.org, catalin.marinas@arm.com, sudeep.holla@arm.com, will@kernel.org, linux@armlinux.org.uk, valentin.schneider@arm.com Cc: mingo@redhat.com, peterz@infradead.org, dietmar.eggemann@arm.com, ionela.voinescu@arm.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/8] cpufreq: report whether cpufreq supports Frequency Invariance (FI) Date: Wed, 1 Jul 2020 10:07:48 +0100 Message-Id: <20200701090751.7543-6-ionela.voinescu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200701090751.7543-1-ionela.voinescu@arm.com> References: <20200701090751.7543-1-ionela.voinescu@arm.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Now that the update of the FI scale factor is done in cpufreq core for selected functions - target_index() and fast_switch(), and drivers can mark themselves as providing custom support for FI as well, by calling arch_set_freq_scale() themselves, we can provide feedback to the task scheduler (and not only) on whether cpufreq supports FI. For this purpose, provide error and debug messages, together with an external function to expose whether the cpufreq drivers support FI, by using a static key. Signed-off-by: Ionela Voinescu Cc: Rafael J. Wysocki Cc: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 26 ++++++++++++++++++++++++++ include/linux/cpufreq.h | 5 +++++ 2 files changed, 31 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 83b58483a39b..60b5272c5d80 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -59,6 +59,9 @@ static struct cpufreq_driver *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); static DEFINE_RWLOCK(cpufreq_driver_lock); +/* Mark support for the scheduler's frequency invariance engine */ +static DEFINE_STATIC_KEY_FALSE(cpufreq_set_freq_scale); + /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended; @@ -67,6 +70,26 @@ static inline bool has_target(void) return cpufreq_driver->target_index || cpufreq_driver->target; } +static inline +void enable_cpufreq_freq_invariance(struct cpufreq_driver *driver) +{ + if ((driver->flags & CPUFREQ_CUSTOM_SET_FREQ_SCALE) || + ((driver->target_index || driver->fast_switch) + && !(driver->target || driver->setpolicy))) { + + static_branch_enable_cpuslocked(&cpufreq_set_freq_scale); + pr_debug("%s: Driver %s can provide frequency invariance.", + __func__, driver->name); + } else + pr_err("%s: Driver %s cannot provide frequency invariance.", + __func__, driver->name); +} + +bool cpufreq_sets_freq_scale(void) +{ + return static_branch_likely(&cpufreq_set_freq_scale); +} + /* internal prototypes */ static unsigned int __cpufreq_get(struct cpufreq_policy *policy); static int cpufreq_init_governor(struct cpufreq_policy *policy); @@ -2713,6 +2736,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) cpufreq_driver = driver_data; write_unlock_irqrestore(&cpufreq_driver_lock, flags); + enable_cpufreq_freq_invariance(cpufreq_driver); + if (driver_data->setpolicy) driver_data->flags |= CPUFREQ_CONST_LOOPS; @@ -2782,6 +2807,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) cpus_read_lock(); subsys_interface_unregister(&cpufreq_interface); remove_boost_sysfs_file(); + static_branch_disable_cpuslocked(&cpufreq_set_freq_scale); cpuhp_remove_state_nocalls_cpuslocked(hp_online); write_lock_irqsave(&cpufreq_driver_lock, flags); diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 42668588f9f8..8b6369d657bd 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -217,6 +217,7 @@ void refresh_frequency_limits(struct cpufreq_policy *policy); void cpufreq_update_policy(unsigned int cpu); void cpufreq_update_limits(unsigned int cpu); bool have_governor_per_policy(void); +bool cpufreq_sets_freq_scale(void); struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy); void cpufreq_enable_fast_switch(struct cpufreq_policy *policy); void cpufreq_disable_fast_switch(struct cpufreq_policy *policy); @@ -237,6 +238,10 @@ static inline unsigned int cpufreq_get_hw_max_freq(unsigned int cpu) { return 0; } +static inline bool cpufreq_sets_freq_scale(void) +{ + return false; +} static inline void disable_cpufreq(void) { } #endif