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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 2591FC432C3 for ; Thu, 21 Nov 2019 23:16:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDBCF20637 for ; Thu, 21 Nov 2019 23:16:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="RLW2Z2ol" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726265AbfKUXQ2 (ORCPT ); Thu, 21 Nov 2019 18:16:28 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:37034 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726038AbfKUXQ2 (ORCPT ); Thu, 21 Nov 2019 18:16:28 -0500 Received: by mail-pf1-f194.google.com with SMTP id p24so2527293pfn.4 for ; Thu, 21 Nov 2019 15:16:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8sWPzcCwJjLfWeGoew09hehB2qcRrNVbdZlAGvSzZ/4=; b=RLW2Z2ol/mCAxqaWtd7Zi/Y7HonJe7Yg/sTnXVvWkTPLtR8+wdOhbP+fQkwEJxMM5q wZCt7iop3j3b6nUvhpyEqnnXI3O3XJyNgnqqS7t0oYwfD6bLjKyKFZkqcn1lU7ayyAbw dDtWqpj4bGgUJmvodg9wj3KF6DbUERwcU22wM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8sWPzcCwJjLfWeGoew09hehB2qcRrNVbdZlAGvSzZ/4=; b=CPKo67bUNu34Q8s4i2ce9XPHWL/oOKO8Z8rgtx6tyeH1mFoWnZls4Kv5eVBhJBfEe+ sz6pE9Ytx/lCURvyiY3BnqRGMJVHxoBLreQwhSrwD0tinUTE22xwD/F+00fX/bjE6kK2 scVGlDlQS5OnAcXFCu7faQw+3ZPV17JBKHrJz1BQtMHM3KeNVnYkmEPjETQ2Uf6xQF6Z u8Fg7HFCIQkRY5vvTgxBB09gAxqfLOHM+yHYX4DL1Hhag7dadC8a1oyR6/4JsZPy2qox JwSXmEjl4c98A2z4RBGqHEEIaSvv6nloOJAKlGpqRnOqqsdNMVd6M3Nwgjq2lQfyw6dt yWdg== X-Gm-Message-State: APjAAAUxPWlFud08Tj7DyivrR0qXGtBRJOanuJHtArrPrZh9IUOpU/XG MzfMdqa3ROE48bpuBK2ClLnXJg== X-Google-Smtp-Source: APXvYqzDaN/gUHbALcy0iPAeUp0twk7ht0phtka4mb2z5ujRvgii3zwCv6/WBeA1/7RLRW3MF/Y5AA== X-Received: by 2002:a62:7553:: with SMTP id q80mr14378924pfc.203.1574378185361; Thu, 21 Nov 2019 15:16:25 -0800 (PST) Received: from localhost ([2620:15c:202:1:4fff:7a6b:a335:8fde]) by smtp.gmail.com with ESMTPSA id f10sm4713293pfd.28.2019.11.21.15.16.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Nov 2019 15:16:24 -0800 (PST) Date: Thu, 21 Nov 2019 15:16:22 -0800 From: Matthias Kaehlcke To: Leonard Crestez Cc: Chanwoo Choi , "Rafael J. Wysocki" , Kyungmin Park , MyungJoo Ham , Artur =?utf-8?B?xZp3aWdvxYQ=?= , Saravana Kannan , Krzysztof Kozlowski , Alexandre Bailon , Georgi Djakov , Jacky Bai , Viresh Kumar , NXP Linux Team , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH RFC 2/2] PM / devfreq: Use PM QoS for sysfs min/max_freq Message-ID: <20191121231622.GK27773@google.com> References: <1f567d6478b1782f7f4afc27cb6d3f896d77ac9f.1574179738.git.leonard.crestez@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1f567d6478b1782f7f4afc27cb6d3f896d77ac9f.1574179738.git.leonard.crestez@nxp.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Leonard, this seems to work ok as long as there are no other ('external') PM QoS requests, however the aggregate max_freq can be incorrect when there are multiple requests. I intended to test with devfreq_cooling using PM QoS, but this didn't work out due to limitations on my development platform. Instead I added another set of requests and sysfs attributes to devfreq (see patch below). With this we get: cat available_frequencies 180000000 267000000 355000000 430000000 565000000 650000000 800000000 # ok cat max_freq 800000000 # wtf??? echo 650000000 > max_freq cat max_freq 800000000 # this looks better echo 800000000 > test_max_freq cat max_freq 650000000 The problem appears to be: #define PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE (-1) in include/linux/pm_qos.h (added by "PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY") The aggregate value returned by dev_pm_qos_read_value(dev, DEV_PM_QOS_MAX_FREQUENCY) is the smallest of all requests, which is PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE unless all requests have set an actual constraint. You probably want to change the constant to resolve to S32_MAX or some other big value. Cheers Matthias diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 4e6b3c05b3706f..935098bfadf944 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -659,6 +659,18 @@ static void devfreq_dev_release(struct device *dev) dev_warn(dev->parent, "Failed to remove min_freq request: %d\n", err); } + if (dev_pm_qos_request_active(&devfreq->test_max_freq_req)) { + err = dev_pm_qos_remove_request(&devfreq->test_max_freq_req); + if (err) + dev_warn(dev->parent, + "Failed to remove test_max_freq request: %d\n", err); + } + if (dev_pm_qos_request_active(&devfreq->test_min_freq_req)) { + err = dev_pm_qos_remove_request(&devfreq->test_min_freq_req); + if (err) + dev_warn(dev->parent, + "Failed to remove test_min_freq request: %d\n", err); + } if (devfreq->profile->exit) devfreq->profile->exit(devfreq->dev.parent); @@ -738,6 +750,16 @@ struct devfreq *devfreq_add_device(struct device *dev, if (err < 0) goto err_dev; + err = dev_pm_qos_add_request(dev, &devfreq->test_min_freq_req, + DEV_PM_QOS_MIN_FREQUENCY, 0); + if (err < 0) + goto err_dev; + err = dev_pm_qos_add_request(dev, &devfreq->test_max_freq_req, + DEV_PM_QOS_MAX_FREQUENCY, + PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE); + if (err < 0) + goto err_dev; + devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); devfreq->opp_table = dev_pm_opp_get_opp_table(dev); if (IS_ERR(devfreq->opp_table)) @@ -1454,6 +1476,101 @@ static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(max_freq); +static ssize_t test_min_freq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long value; + int ret; + + /* + * Protect against theoretical sysfs writes between + * device_add and dev_pm_qos_add_request + */ + if (!dev_pm_qos_request_active(&df->test_min_freq_req)) + return -EINVAL; + + ret = sscanf(buf, "%lu", &value); + if (ret != 1) + return -EINVAL; + + /* Round down to kHz for PM QoS */ + ret = dev_pm_qos_update_request(&df->test_min_freq_req, + value / HZ_PER_KHZ); + if (ret < 0) + return ret; + + return count; +} + +static ssize_t test_min_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long min_freq, max_freq; + + mutex_lock(&df->lock); + get_freq_range(df, &min_freq, &max_freq); + mutex_unlock(&df->lock); + + return sprintf(buf, "%lu\n", min_freq); +} + +static ssize_t test_max_freq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long value; + int ret; + + /* + * Protect against theoretical sysfs writes between + * device_add and dev_pm_qos_add_request + */ + if (!dev_pm_qos_request_active(&df->test_max_freq_req)) + return -EINVAL; + + ret = sscanf(buf, "%lu", &value); + if (ret != 1) + return -EINVAL; + + /* + * PM QoS frequencies are in kHz so we need to convert. Convert by + * rounding upwards so that the acceptable interval never shrinks. + * + * For example if the user writes "666666666" to sysfs this value will + * be converted to 666667 kHz and back to 666667000 Hz before an OPP + * lookup, this ensures that an OPP of 666666666Hz is still accepted. + * + * A value of zero means "no limit". + */ + if (value) + value = DIV_ROUND_UP(value, HZ_PER_KHZ); + else + value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE; + + ret = dev_pm_qos_update_request(&df->test_max_freq_req, value); + if (ret < 0) + return ret; + + return count; +} +static DEVICE_ATTR_RW(test_min_freq); + +static ssize_t test_max_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long min_freq, max_freq; + + mutex_lock(&df->lock); + get_freq_range(df, &min_freq, &max_freq); + mutex_unlock(&df->lock); + + return sprintf(buf, "%lu\n", max_freq); +} +static DEVICE_ATTR_RW(test_max_freq); + static ssize_t available_frequencies_show(struct device *d, struct device_attribute *attr, char *buf) @@ -1532,6 +1649,8 @@ static struct attribute *devfreq_attrs[] = { &dev_attr_polling_interval.attr, &dev_attr_min_freq.attr, &dev_attr_max_freq.attr, + &dev_attr_test_min_freq.attr, + &dev_attr_test_max_freq.attr, &dev_attr_trans_stat.attr, NULL, }; diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 6cdd070d59c1f2..8f97c1efaacca5 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -166,6 +166,8 @@ struct devfreq { struct dev_pm_qos_request user_min_freq_req; struct dev_pm_qos_request user_max_freq_req; + +static ssize_t test_max_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long min_freq, max_freq; + + mutex_lock(&df->lock); + get_freq_range(df, &min_freq, &max_freq); + mutex_unlock(&df->lock); + + return sprintf(buf, "%lu\n", max_freq); +} +static DEVICE_ATTR_RW(test_max_freq); + static ssize_t available_frequencies_show(struct device *d, struct device_attribute *attr, char *buf) @@ -1532,6 +1649,8 @@ static struct attribute *devfreq_attrs[] = { &dev_attr_polling_interval.attr, &dev_attr_min_freq.attr, &dev_attr_max_freq.attr, + &dev_attr_test_min_freq.attr, + &dev_attr_test_max_freq.attr, &dev_attr_trans_stat.attr, NULL, }; diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 6cdd070d59c1f2..8f97c1efaacca5 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -166,6 +166,8 @@ struct devfreq { struct dev_pm_qos_request user_min_freq_req; struct dev_pm_qos_request user_max_freq_req; + struct dev_pm_qos_request test_min_freq_req; + struct dev_pm_qos_request test_max_freq_req; bool stop_polling; unsigned long suspend_freq; On Tue, Nov 19, 2019 at 06:12:14PM +0200, Leonard Crestez wrote: > Switch the handling of min_freq and max_freq from sysfs to use the > dev_pm_qos_request interface. > > Since PM QoS handles frequencies as kHz this change reduces the > precision of min_freq and max_freq. This shouldn't introduce problems > because frequencies which are not an integer number of kHz are likely > not an integer number of Hz either. > > Try to ensure compatibility by rounding min values down and rounding > max values up. > > Signed-off-by: Leonard Crestez > --- > drivers/devfreq/devfreq.c | 76 ++++++++++++++++++++++++++++++--------- > include/linux/devfreq.h | 9 ++--- > 2 files changed, 64 insertions(+), 21 deletions(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 34bbaac6ea7e..518dd2745d06 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -139,14 +139,10 @@ static void get_freq_range(struct devfreq *devfreq, > *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq); > if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE) > *max_freq = min(*max_freq, > (unsigned long)HZ_PER_KHZ * qos_max_freq); > > - /* Apply constraints from sysfs */ > - *min_freq = max(*min_freq, devfreq->min_freq); > - *max_freq = min(*max_freq, devfreq->max_freq); > - > /* Apply constraints from OPP interface */ > *min_freq = max(*min_freq, devfreq->scaling_min_freq); > *max_freq = min(*max_freq, devfreq->scaling_max_freq); > > if (*min_freq > *max_freq) > @@ -708,10 +704,23 @@ static void devfreq_dev_release(struct device *dev) > DEV_PM_QOS_MIN_FREQUENCY); > if (err && err != -ENOENT) > dev_warn(dev->parent, > "Failed to remove min_freq notifier: %d\n", err); > > + if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) { > + err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req); > + if (err) > + dev_warn(dev->parent, > + "Failed to remove max_freq request: %d\n", err); > + } > + if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) { > + err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req); > + if (err) > + dev_warn(dev->parent, > + "Failed to remove min_freq request: %d\n", err); > + } > + > if (devfreq->profile->exit) > devfreq->profile->exit(devfreq->dev.parent); > > mutex_destroy(&devfreq->lock); > kfree(devfreq); > @@ -780,19 +789,17 @@ struct devfreq *devfreq_add_device(struct device *dev, > if (!devfreq->scaling_min_freq) { > mutex_unlock(&devfreq->lock); > err = -EINVAL; > goto err_dev; > } > - devfreq->min_freq = devfreq->scaling_min_freq; > > devfreq->scaling_max_freq = find_available_max_freq(devfreq); > if (!devfreq->scaling_max_freq) { > mutex_unlock(&devfreq->lock); > err = -EINVAL; > goto err_dev; > } > - devfreq->max_freq = devfreq->scaling_max_freq; > > devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); > atomic_set(&devfreq->suspend_count, 0); > > dev_set_name(&devfreq->dev, "devfreq%d", > @@ -829,10 +836,20 @@ struct devfreq *devfreq_add_device(struct device *dev, > > srcu_init_notifier_head(&devfreq->transition_notifier_list); > > mutex_unlock(&devfreq->lock); > > + err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req, > + DEV_PM_QOS_MIN_FREQUENCY, 0); > + if (err < 0) > + goto err_devfreq; > + err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req, > + DEV_PM_QOS_MAX_FREQUENCY, > + PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE); > + if (err < 0) > + goto err_devfreq; > + > devfreq->nb_min.notifier_call = qos_min_notifier_call; > err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min, > DEV_PM_QOS_MIN_FREQUENCY); > if (err) > goto err_devfreq; > @@ -1414,18 +1431,26 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, > { > struct devfreq *df = to_devfreq(dev); > unsigned long value; > int ret; > > + /* > + * Protect against theoretical sysfs writes between > + * device_add and dev_pm_qos_add_request > + */ > + if (!dev_pm_qos_request_active(&df->user_min_freq_req)) > + return -EINVAL; > + > ret = sscanf(buf, "%lu", &value); > if (ret != 1) > return -EINVAL; > > - mutex_lock(&df->lock); > - df->min_freq = value; > - update_devfreq(df); > - mutex_unlock(&df->lock); > + /* Round down to kHz for PM QoS */ > + ret = dev_pm_qos_update_request(&df->user_min_freq_req, > + value / HZ_PER_KHZ); > + if (ret < 0) > + return ret; > > return count; > } > > static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr, > @@ -1446,22 +1471,39 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, > { > struct devfreq *df = to_devfreq(dev); > unsigned long value; > int ret; > > + /* > + * Protect against theoretical sysfs writes between > + * device_add and dev_pm_qos_add_request > + */ > + if (!dev_pm_qos_request_active(&df->user_max_freq_req)) > + return -EINVAL; > + > ret = sscanf(buf, "%lu", &value); > if (ret != 1) > return -EINVAL; > > - mutex_lock(&df->lock); > - > - if (!value) > - value = ULONG_MAX; > + /* > + * PM QoS frequencies are in kHz so we need to convert. Convert by > + * rounding upwards so that the acceptable interval never shrinks. > + * > + * For example if the user writes "666666666" to sysfs this value will > + * be converted to 666667 kHz and back to 666667000 Hz before an OPP > + * lookup, this ensures that an OPP of 666666666Hz is still accepted. > + * > + * A value of zero means "no limit". > + */ > + if (value) > + value = DIV_ROUND_UP(value, HZ_PER_KHZ); > + else > + value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE; > > - df->max_freq = value; > - update_devfreq(df); > - mutex_unlock(&df->lock); > + ret = dev_pm_qos_update_request(&df->user_max_freq_req, value); > + if (ret < 0) > + return ret; > > return count; > } > static DEVICE_ATTR_RW(min_freq); > > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h > index 8b92ccbd1962..fb376b5b7281 100644 > --- a/include/linux/devfreq.h > +++ b/include/linux/devfreq.h > @@ -11,10 +11,11 @@ > #define __LINUX_DEVFREQ_H__ > > #include > #include > #include > +#include > > #define DEVFREQ_NAME_LEN 16 > > /* DEVFREQ governor name */ > #define DEVFREQ_GOV_SIMPLE_ONDEMAND "simple_ondemand" > @@ -121,12 +122,12 @@ struct devfreq_dev_profile { > * devfreq.nb to the corresponding register notifier call chain. > * @work: delayed work for load monitoring. > * @previous_freq: previously configured frequency value. > * @data: Private data of the governor. The devfreq framework does not > * touch this. > - * @min_freq: Limit minimum frequency requested by user (0: none) > - * @max_freq: Limit maximum frequency requested by user (0: none) > + * @user_min_freq_req: PM QoS minimum frequency request from user (via sysfs) > + * @user_max_freq_req: PM QoS maximum frequency request from user (via sysfs) > * @scaling_min_freq: Limit minimum frequency requested by OPP interface > * @scaling_max_freq: Limit maximum frequency requested by OPP interface > * @stop_polling: devfreq polling status of a device. > * @suspend_freq: frequency of a device set during suspend phase. > * @resume_freq: frequency of a device set in resume phase. > @@ -161,12 +162,12 @@ struct devfreq { > unsigned long previous_freq; > struct devfreq_dev_status last_status; > > void *data; /* private data for governors */ > > - unsigned long min_freq; > - unsigned long max_freq; > + struct dev_pm_qos_request user_min_freq_req; > + struct dev_pm_qos_request user_max_freq_req; > unsigned long scaling_min_freq; > unsigned long scaling_max_freq; > bool stop_polling; > > unsigned long suspend_freq; > -- > 2.17.1 >