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 X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FEA1C433E0 for ; Mon, 15 Jun 2020 16:56:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09AFA20663 for ; Mon, 15 Jun 2020 16:56:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cuJ222JF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731055AbgFOQ4F (ORCPT ); Mon, 15 Jun 2020 12:56:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730995AbgFOQ4D (ORCPT ); Mon, 15 Jun 2020 12:56:03 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E43CC061A0E for ; Mon, 15 Jun 2020 09:56:02 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id l6so14736156qkk.14 for ; Mon, 15 Jun 2020 09:56:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=rmttyKz0sTdI4/Wk+GTFfxu2WU1sGb9iqnCsy3KIwVE=; b=cuJ222JFgG6Wav6PHDylftDoc7puvRPmG+8eTu72bSGUEDOtWWfL4+qfs6opmi6DwM k4fhKoIQPuntLywxeo0hKhCsK4qsCMCRBF9tXG4SMjRayA2OsSVe2gtEohxjRthTVwsg 2PRIQ+MXqxwI7h7FPzvHSRwfcVFwqQIfAQ6fhzP6emUXWKLfQCdRtQUVR1SixDh2VnUZ kbeu7Uwf9js422PujgnJcqmE/g3U4No3d/Pk+2Y9V8Z8/6B/5B+0a93k9ivzVPoe67O9 rYMK+R/DUuGXU5RI1/kRC4kPtS7CMq8C5b+vJH5vEJ0fR1ZG7DUOx3RL1ptqOLpng+bP nBzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=rmttyKz0sTdI4/Wk+GTFfxu2WU1sGb9iqnCsy3KIwVE=; b=KZGEvl9uCqFC46fIqpTF7DzubF5HIeZUXl5QmiqqbuCZ7TUDGDFtG200O1V5Lpaumx rbBmb8qLfiyBVkpd+c9/oaEIeMFxe6sc1FtN9Z9FV3udwzY8sdN0bui2LZOzQLlLq8lv IaJkUBYP7q2oTImpH93q5N62YZryedLxnyxmyBOT484fogfnnWYW96LvJp1Z3PQUkhBJ Avd2gcvPaTEbG/C/Uyaj1axcdeoIKAxvYlG63GOjB9QPh+CLhSFu7g/348Zs3KTMj/GT Csj+OaK0dWj8+T8OoeNDmf0kxZ9DQOgX17HfHolzwczvigjTOUivdtUUDXPWI4l51/qq UAvQ== X-Gm-Message-State: AOAM531r5jk/kHDZ5k2TJvtvipoUGgG16EpPWXTTP/aEB0i3sv9SpsM5 nVFHCb7KsqVpBZ+sjY7jQtsfcq416hxe X-Google-Smtp-Source: ABdhPJxu0sj2E89tKcmQTaKcRjumvWg2bCjfwFUYPI2vq1B6zd2GBouCZQ6YlWOEiSqJmqO1hAUpGCE4vThl X-Received: by 2002:ad4:43c8:: with SMTP id o8mr26494403qvs.235.1592240161344; Mon, 15 Jun 2020 09:56:01 -0700 (PDT) Date: Mon, 15 Jun 2020 17:55:54 +0100 In-Reply-To: <20200615165554.228063-1-qperret@google.com> Message-Id: <20200615165554.228063-3-qperret@google.com> Mime-Version: 1.0 References: <20200615165554.228063-1-qperret@google.com> X-Mailer: git-send-email 2.27.0.290.gba653c62da-goog Subject: [PATCH 2/2] cpufreq: Specify default governor on command line From: Quentin Perret To: rjw@rjwysocki.net, rafael@kernel.org, viresh.kumar@linaro.org Cc: arnd@arndb.de, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, kernel-team@android.com, qperret@google.com, tkjos@google.com, adharmap@codeaurora.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, the only way to specify the default CPUfreq governor is via Kconfig options, which suits users who can build the kernel themselves perfectly. However, for those who use a distro-like kernel (such as Android, with the Generic Kernel Image project), the only way to use a different default is to boot to userspace, and to then switch using the sysfs interface. Being able to specify the default governor on the command line, like is the case for cpuidle, would enable those users to specify their governor of choice earlier on, and to simplify slighlty the userspace boot procedure. To support this use-case, add a kernel command line parameter enabling to specify a default governor for CPUfreq, which takes precedence over the builtin default. This implementation has one notable limitation: the default governor must be registered before the driver. This is solved for builtin governors and drivers using appropriate *_initcall() functions. And in the modular case, this must be reflected as a constraint on the module loading order. Signed-off-by: Quentin Perret --- .../admin-guide/kernel-parameters.txt | 5 +++ Documentation/admin-guide/pm/cpufreq.rst | 6 ++-- drivers/cpufreq/cpufreq.c | 34 ++++++++++++++++--- 3 files changed, 37 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb95fad81c79..5fd3c9f187eb 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -703,6 +703,11 @@ cpufreq.off=1 [CPU_FREQ] disable the cpufreq sub-system + cpufreq.default_governor= + [CPU_FREQ] Name of the default cpufreq governor to use. + This governor must be registered in the kernel before + the cpufreq driver probes. + cpu_init_udelay=N [X86] Delay for N microsec between assert and de-assert of APIC INIT to start processors. This delay occurs diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst index 0c74a7784964..368e612145d2 100644 --- a/Documentation/admin-guide/pm/cpufreq.rst +++ b/Documentation/admin-guide/pm/cpufreq.rst @@ -147,9 +147,9 @@ CPUs in it. The next major initialization step for a new policy object is to attach a scaling governor to it (to begin with, that is the default scaling governor -determined by the kernel configuration, but it may be changed later -via ``sysfs``). First, a pointer to the new policy object is passed to the -governor's ``->init()`` callback which is expected to initialize all of the +determined by the kernel command line or configuration, but it may be changed +later via ``sysfs``). First, a pointer to the new policy object is passed to +the governor's ``->init()`` callback which is expected to initialize all of the data structures necessary to handle the given policy and, possibly, to add a governor ``sysfs`` interface to it. Next, the governor is started by invoking its ``->start()`` callback. diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 0128de3603df..0f05caedc320 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -50,6 +50,9 @@ static LIST_HEAD(cpufreq_governor_list); #define for_each_governor(__governor) \ list_for_each_entry(__governor, &cpufreq_governor_list, governor_list) +static char cpufreq_param_governor[CPUFREQ_NAME_LEN]; +static struct cpufreq_governor *default_governor; + /** * The "cpufreq driver" - the arch- or hardware-dependent low * level driver of CPUFreq support, and its spinlock. This lock @@ -1055,7 +1058,6 @@ __weak struct cpufreq_governor *cpufreq_default_governor(void) static int cpufreq_init_policy(struct cpufreq_policy *policy) { - struct cpufreq_governor *def_gov = cpufreq_default_governor(); struct cpufreq_governor *gov = NULL; unsigned int pol = CPUFREQ_POLICY_UNKNOWN; @@ -1065,8 +1067,8 @@ static int cpufreq_init_policy(struct cpufreq_policy *policy) if (gov) { pr_debug("Restoring governor %s for cpu %d\n", policy->governor->name, policy->cpu); - } else if (def_gov) { - gov = def_gov; + } else if (default_governor) { + gov = default_governor; } else { return -ENODATA; } @@ -1074,8 +1076,8 @@ static int cpufreq_init_policy(struct cpufreq_policy *policy) /* Use the default policy if there is no last_policy. */ if (policy->last_policy) { pol = policy->last_policy; - } else if (def_gov) { - pol = cpufreq_parse_policy(def_gov->name); + } else if (default_governor) { + pol = cpufreq_parse_policy(default_governor->name); /* * In case the default governor is neiter "performance" * nor "powersave", fall back to the initial policy @@ -2196,6 +2198,24 @@ __weak struct cpufreq_governor *cpufreq_fallback_governor(void) return NULL; } +static void cpufreq_get_default_governor(void) +{ + default_governor = cpufreq_parse_governor(cpufreq_param_governor); + if (!default_governor) { + if (*cpufreq_param_governor) + pr_warn("Failed to find %s\n", cpufreq_param_governor); + default_governor = cpufreq_default_governor(); + } +} + +static void cpufreq_put_default_governor(void) +{ + if (!default_governor) + return; + module_put(default_governor->owner); + default_governor = NULL; +} + static int cpufreq_init_governor(struct cpufreq_policy *policy) { int ret; @@ -2701,6 +2721,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) if (driver_data->setpolicy) driver_data->flags |= CPUFREQ_CONST_LOOPS; + else + cpufreq_get_default_governor(); if (cpufreq_boost_supported()) { ret = create_boost_sysfs_file(); @@ -2769,6 +2791,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) subsys_interface_unregister(&cpufreq_interface); remove_boost_sysfs_file(); cpuhp_remove_state_nocalls_cpuslocked(hp_online); + cpufreq_put_default_governor(); write_lock_irqsave(&cpufreq_driver_lock, flags); @@ -2792,4 +2815,5 @@ static int __init cpufreq_core_init(void) return 0; } module_param(off, int, 0444); +module_param_string(default_governor, cpufreq_param_governor, CPUFREQ_NAME_LEN, 0444); core_initcall(cpufreq_core_init); -- 2.27.0.290.gba653c62da-goog