From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CH4PR04CU002.outbound.protection.outlook.com (mail-northcentralusazon11013049.outbound.protection.outlook.com [40.107.201.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 931361F8BD6; Tue, 25 Nov 2025 04:56:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.201.49 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764046589; cv=fail; b=rjiTIkztw3YS1U4PFpiN/Ssrx7zRS8PgE2DvzZTDotrdvrc4uzKthLKPHFwhcesZ2pMbQm1H6yhO5WS94WzV8o5H2voqo1+qc3hvD8w6k++bK1Wyk37lqdJbEHvtt2IinN5biU0k4BuNr7XB3kPVjY8cW8ee9+Q+l/G/Iu3SWsY= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764046589; c=relaxed/simple; bh=SHpja7qrgrV3BbyzRDKdJpN8g7oXVy1RozrgfMEYYMg=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CkT6BKDn1iHvGwc+mCuZpTm/yH4g9fO9iVW1lfmfsxnmNwwWpVoU6i0aCEMHH+jJGgdP5i+Vuef96nvaoOKF5ovet7ftYMRi2wK9v81OsH96l3PJDb4eYwYuEdE5wLc+iBQ7bGqcHN5wg8UPL9+Mqwwd5WllM2L68fU6w50fi6M= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com; spf=pass smtp.mailfrom=ti.com; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b=OvzJrdwU; arc=fail smtp.client-ip=40.107.201.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ti.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="OvzJrdwU" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=HyhCUJxh3Ncg548LVARxpp9AfZR6SSo1neemh9Je9qu1W7pvKU1fMdI6N9ngRgH/QfooJ+DRvJPGx+/rD6VFiOBmH941sICDdsrtY1QR+h9Wbbs8QSWX5QaFHLGsmWNM1A+XA+4lagjbmv7DqtrrOXl+WvP/qdD4rGQpZFuF9RX8BZI/C+gm7D3P3egHNADDzZzq/dxggdJwNGjxawc2zHF+p7KpHI0a8IzWPZWVlvNzhQcQ6haMf5UfwzKdOBmLNEJ8r+8hkyZzTubGqn8wf567drjIsfJ5JUxNBJsqaEiloqeYmWH07ddEtZv8kVDPM3QRd7ztNnzigsD+DFZjPw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=36GB82WAbKHaqh+/VnUv/5FSkTwkXmI21zDHZYfZlAo=; b=Twko5pnAZk89cLwbH2Crz7Ua7Ajp4UsXzsLNR6eXj2hGm+an2QDrjwd6gPRhLvmtni1VHlogNdBV1d6JJBz6ZF4qulmnvCDXiHyWOgdesiV+h+8eugzxFecJxTAlYyqZmIOMn+07boP61gMKcVdEDiA/cedwTKgEthD8Jxqwf7HbPeUZrX4J/8TXlTNE/Hu643TcFtHG9+zqYoFqBHXqcm2KB6oQpcMDjecATG7boOxNAMbihtaKZqQrjmAZNPX2sM+vpUtO4H6sssw5G6Q1rE2cRF6LnQem/TS7ZgOCfxSVTqMP/K2wqdg4nzDAqdKc9C7WLRI1zOfD61RgM9uqZQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 198.47.21.194) smtp.rcpttodomain=vger.kernel.org smtp.mailfrom=ti.com; dmarc=pass (p=quarantine sp=none pct=100) action=none header.from=ti.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=36GB82WAbKHaqh+/VnUv/5FSkTwkXmI21zDHZYfZlAo=; b=OvzJrdwUuUhtkIYEXUzOkaO47afOe5OvAKE7sxkqmy7OyzG4mi1jFyj5NOZ25vA4B+iQ1id7+C6KPaVYuNByMhDyTu9dZsTS5FaLacwyxaf3bMeDDsXV/k+QoC7o5o2muHRzdyJpmzJg9cXLGE3e9dIBHcm65ZRrMYC0Sczokwg= Received: from CH0PR03CA0255.namprd03.prod.outlook.com (2603:10b6:610:e5::20) by IA0PR10MB6841.namprd10.prod.outlook.com (2603:10b6:208:437::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9343.17; Tue, 25 Nov 2025 04:56:23 +0000 Received: from CH2PEPF0000013B.namprd02.prod.outlook.com (2603:10b6:610:e5:cafe::9a) by CH0PR03CA0255.outlook.office365.com (2603:10b6:610:e5::20) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9343.18 via Frontend Transport; Tue, 25 Nov 2025 04:56:07 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 198.47.21.194) smtp.mailfrom=ti.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=ti.com; Received-SPF: Pass (protection.outlook.com: domain of ti.com designates 198.47.21.194 as permitted sender) receiver=protection.outlook.com; client-ip=198.47.21.194; helo=flwvzet200.ext.ti.com; pr=C Received: from flwvzet200.ext.ti.com (198.47.21.194) by CH2PEPF0000013B.mail.protection.outlook.com (10.167.244.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9366.7 via Frontend Transport; Tue, 25 Nov 2025 04:56:21 +0000 Received: from DFLE114.ent.ti.com (10.64.6.35) by flwvzet200.ext.ti.com (10.248.192.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.2.2562.20; Mon, 24 Nov 2025 22:56:20 -0600 Received: from DFLE214.ent.ti.com (10.64.6.72) by DFLE114.ent.ti.com (10.64.6.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.55; Mon, 24 Nov 2025 22:56:20 -0600 Received: from lelvem-mr06.itg.ti.com (10.180.75.8) by DFLE214.ent.ti.com (10.64.6.72) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20 via Frontend Transport; Mon, 24 Nov 2025 22:56:20 -0600 Received: from localhost (lcpd911.dhcp.ti.com [172.24.233.130]) by lelvem-mr06.itg.ti.com (8.18.1/8.18.1) with ESMTP id 5AP4uJQ23107134; Mon, 24 Nov 2025 22:56:19 -0600 Date: Tue, 25 Nov 2025 10:26:18 +0530 From: Dhruva Gole To: Ulf Hansson CC: "Rafael J . Wysocki" , , Vincent Guittot , Peter Zijlstra , Kevin Hilman , Pavel Machek , Len Brown , Daniel Lezcano , Maulik Shah , "Prasad Sodagudi" , Deepti Jaggi , Subject: Re: [PATCH v3 1/6] PM: QoS: Introduce a CPU system wakeup QoS limit Message-ID: <20251125045618.texoubmzmiz7cz6c@lcpd911> References: <20251121100315.316300-1-ulf.hansson@linaro.org> <20251121100315.316300-2-ulf.hansson@linaro.org> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20251121100315.316300-2-ulf.hansson@linaro.org> X-C2ProcessedOrg: 333ef613-75bf-4e12-a4b1-8e3623f5dcea X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PEPF0000013B:EE_|IA0PR10MB6841:EE_ X-MS-Office365-Filtering-Correlation-Id: b27f2e16-a7ab-4d43-240f-08de2bdefa4e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|1800799024|376014|7416014|36860700013; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?/mgCeCVYOIDgOIdFU1QDhavjTynDiPyaTKZmu3FH80xHc1sJSo8oa1qY0h2P?= =?us-ascii?Q?Eqt0A/8g/VzlqmUfrE3kyHhAgS9UyX6y6YRixTgnJHQ9hrxB9rJBObHb/30e?= =?us-ascii?Q?sX7Dz0hcF09ohC62wvIp+L+EeIgkvkxagr4Yxh6UPfeYYeGHO/gEPkir60Yb?= =?us-ascii?Q?zInQ9ZqFeiZsuiqKOI5YkGm7Q86CdaioJjM+wVhiNQnI+msSp3qPPtuNn3+1?= =?us-ascii?Q?icOox0oSXKl2Gh8jiJq9heiaZljI1u8Se+qKFpa9BpdRQL06w33BFdlDbbNL?= =?us-ascii?Q?g9OzOfaEvBXijRkh047EPqWF5eb/wmGBzfl5j5dP8NhUVhSFsuelNI9+20sa?= =?us-ascii?Q?UCukczarGKyT5/HkRHND1V8ztfZSNypdWK14eblVwTC9g1f/rc9+gL6oB5Xv?= =?us-ascii?Q?wLBAxbIuj0Oc/cXpxpc8Ao9iS0XsaorrL6uhQmmiJDj5hMUtAYt+xv81BhEl?= =?us-ascii?Q?chg1EncmunlCbJCqba1AG9EmFcGeQN5afkvCaMyQz65r7GudrAg3qmbXrq/9?= =?us-ascii?Q?HQqFxzWEDhjjL+nLEesLI0tq9keqIky4jQ/mQOULfmXyI03TTbxcVk4jtfJn?= =?us-ascii?Q?gltJtVQOCvjKjlfe/STleXdioMFW+w8kCIAzaHhSuhOYus8MC8O7AglSNoIp?= =?us-ascii?Q?OD7nVVY6ncOe9XmJX8vNvES0ZZuToX4dTsDpwXaNdgOqerZhXKS1dlFLADyc?= =?us-ascii?Q?3bMUJotWaZ6e2weE/R+ii8le+0Otavx3gLtO4JybWEZrV83jQmZWDdwS8B+S?= =?us-ascii?Q?xFswjapGY5g77Tuwo2ZWleid4hIenqmP5SobnmYH/SLyr+KxEQLiVhQbqyHL?= =?us-ascii?Q?777k9qe7POd1pkFoyl1bvDVdlXFcgSDLuup6kBwD3kzJ+BqhFq5t+Zzkk6RK?= =?us-ascii?Q?umT86CiF/lH8Z/4WZXGY8DjAh4rtZ/ALVQk2uWdsmAtwbOFWokS4WuYyaKQu?= =?us-ascii?Q?WM9WW2BOsRiZijxlj/WWIO0ZuV52AoA0rSN3lrhZVkfIxo0cF095sbLuQWxs?= =?us-ascii?Q?TBbkQnyuLU11rkTAuKQlkc0H1UwLtpInfmW6gECl0lLmjLGr2LDM/cvGgerp?= =?us-ascii?Q?N93nVgkyRD+PXYgMRab8bpJT1Gy5CMo3nuVSLo3fsbC30c9/GpST0qd0HppF?= =?us-ascii?Q?XGViZsm9IkxAiDF/ZERXnYs4KYNqx+7tTy9VGyffhKzsX4UGkDeRlqaKQ+1f?= =?us-ascii?Q?GcIxeulQsv/DPUu63hG3epzESvDnobN8lVxE1+a5rl2bHv2ygQW1XHJhsV/G?= =?us-ascii?Q?vycMAPoZwrJHuDvKYJezhVnY6jMBbYwM8DQczDB6T1aJ1dX/8fsVbaWyOjGf?= =?us-ascii?Q?Eu6hW/OOyaj+MQpiUT0KC5kvtgFYq43VY3HR8sERlt+KLEmVExwT+QfYHkGn?= =?us-ascii?Q?9KB/H0EKypDjOtuCaVISAC3qszpVKrSHihTTWbOyeCwrQuDd8niBJr4kVyyu?= =?us-ascii?Q?/IDMK2kFIhXAK7n2UhA/j4YEFf0oaQMeG6uqDmyHGid0Qd4PNC4fPBkeSots?= =?us-ascii?Q?Sj5EHzOLoSROixi37wrR8SPfFaTvboxlQDQ/cyiido8jLQB/nqz84tfGkw9y?= =?us-ascii?Q?kRBV4MRRgyYqnoy5MXc=3D?= X-Forefront-Antispam-Report: CIP:198.47.21.194;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:flwvzet200.ext.ti.com;PTR:ErrorRetry;CAT:NONE;SFS:(13230040)(82310400026)(1800799024)(376014)(7416014)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: ti.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Nov 2025 04:56:21.4676 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b27f2e16-a7ab-4d43-240f-08de2bdefa4e X-MS-Exchange-CrossTenant-Id: e5b49634-450b-4709-8abb-1e2b19b982b7 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=e5b49634-450b-4709-8abb-1e2b19b982b7;Ip=[198.47.21.194];Helo=[flwvzet200.ext.ti.com] X-MS-Exchange-CrossTenant-AuthSource: CH2PEPF0000013B.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR10MB6841 On Nov 21, 2025 at 11:03:07 +0100, Ulf Hansson wrote: > Some platforms supports multiple low power states for CPUs that can be used > when entering system-wide suspend. Currently we are always selecting the > deepest possible state for the CPUs, which can break the system wakeup > latency constraint that may be required for a use case. > > Let's take the first step towards addressing this problem, by introducing > an interface for user space, that allows us to specify the CPU system > wakeup QoS limit. Subsequent changes will start taking into account the new > QoS limit. > > Signed-off-by: Ulf Hansson > --- > > Changes in v3: > - Add Kconfig for the new interface (Rafael). > - Updated commit message. > > Changes in v2: > - Renamings to reflect the QoS are limited to CPUs. > - Move code inside "CONFIG_CPU_IDLE". > --- > include/linux/pm_qos.h | 9 ++++ > kernel/power/Kconfig | 4 ++ > kernel/power/qos.c | 106 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 119 insertions(+) > > diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h > index 4a69d4af3ff8..6cea4455f867 100644 > --- a/include/linux/pm_qos.h > +++ b/include/linux/pm_qos.h > @@ -162,6 +162,15 @@ static inline void cpu_latency_qos_update_request(struct pm_qos_request *req, > static inline void cpu_latency_qos_remove_request(struct pm_qos_request *req) {} > #endif > > +#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP > +s32 cpu_wakeup_latency_qos_limit(void); > +#else > +static inline s32 cpu_wakeup_latency_qos_limit(void) > +{ > + return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; > +} > +#endif > + > #ifdef CONFIG_PM > enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask); > enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask); > diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig > index 54a623680019..839e2dbb889e 100644 > --- a/kernel/power/Kconfig > +++ b/kernel/power/Kconfig > @@ -202,6 +202,10 @@ config PM_WAKELOCKS_GC > depends on PM_WAKELOCKS > default y > > +config PM_QOS_CPU_SYSTEM_WAKEUP > + bool "User space interface for CPU system wakeup QoS" > + depends on CPU_IDLE > + I see that checkpatch complains here with a warning: please write a help paragraph that fully describes the config symbol with at least 4 lines I somewhat agree too, since it's a new and pretty important feature that we're putting behind this config best to add some help around it. With that, Reviewed-by: Dhruva Gole > config PM > bool "Device power management core functionality" > help > diff --git a/kernel/power/qos.c b/kernel/power/qos.c > index 4244b069442e..f7d8064e9adc 100644 > --- a/kernel/power/qos.c > +++ b/kernel/power/qos.c > @@ -415,6 +415,105 @@ static struct miscdevice cpu_latency_qos_miscdev = { > .fops = &cpu_latency_qos_fops, > }; > > +#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP > +/* The CPU system wakeup latency QoS. */ > +static struct pm_qos_constraints cpu_wakeup_latency_constraints = { > + .list = PLIST_HEAD_INIT(cpu_wakeup_latency_constraints.list), > + .target_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, > + .default_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, > + .no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT, > + .type = PM_QOS_MIN, > +}; > + > +/** > + * cpu_wakeup_latency_qos_limit - Current CPU system wakeup latency QoS limit. > + * > + * Returns the current CPU system wakeup latency QoS limit that may have been > + * requested by user space. > + */ > +s32 cpu_wakeup_latency_qos_limit(void) > +{ > + return pm_qos_read_value(&cpu_wakeup_latency_constraints); > +} > + > +static int cpu_wakeup_latency_qos_open(struct inode *inode, struct file *filp) > +{ > + struct pm_qos_request *req; > + > + req = kzalloc(sizeof(*req), GFP_KERNEL); > + if (!req) > + return -ENOMEM; > + > + req->qos = &cpu_wakeup_latency_constraints; > + pm_qos_update_target(req->qos, &req->node, PM_QOS_ADD_REQ, > + PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); > + filp->private_data = req; > + > + return 0; > +} > + > +static int cpu_wakeup_latency_qos_release(struct inode *inode, > + struct file *filp) > +{ > + struct pm_qos_request *req = filp->private_data; > + > + filp->private_data = NULL; > + pm_qos_update_target(req->qos, &req->node, PM_QOS_REMOVE_REQ, > + PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); > + kfree(req); > + > + return 0; > +} > + > +static ssize_t cpu_wakeup_latency_qos_read(struct file *filp, char __user *buf, > + size_t count, loff_t *f_pos) > +{ > + s32 value = pm_qos_read_value(&cpu_wakeup_latency_constraints); > + > + return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32)); > +} > + > +static ssize_t cpu_wakeup_latency_qos_write(struct file *filp, > + const char __user *buf, > + size_t count, loff_t *f_pos) > +{ > + struct pm_qos_request *req = filp->private_data; > + s32 value; > + > + if (count == sizeof(s32)) { > + if (copy_from_user(&value, buf, sizeof(s32))) > + return -EFAULT; > + } else { > + int ret; > + > + ret = kstrtos32_from_user(buf, count, 16, &value); > + if (ret) > + return ret; > + } > + > + if (value < 0) > + return -EINVAL; > + > + pm_qos_update_target(req->qos, &req->node, PM_QOS_UPDATE_REQ, value); > + > + return count; > +} > + > +static const struct file_operations cpu_wakeup_latency_qos_fops = { > + .open = cpu_wakeup_latency_qos_open, > + .release = cpu_wakeup_latency_qos_release, > + .read = cpu_wakeup_latency_qos_read, > + .write = cpu_wakeup_latency_qos_write, > + .llseek = noop_llseek, > +}; > + > +static struct miscdevice cpu_wakeup_latency_qos_miscdev = { > + .minor = MISC_DYNAMIC_MINOR, > + .name = "cpu_wakeup_latency", > + .fops = &cpu_wakeup_latency_qos_fops, > +}; > +#endif /* CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP */ > + > static int __init cpu_latency_qos_init(void) > { > int ret; > @@ -424,6 +523,13 @@ static int __init cpu_latency_qos_init(void) > pr_err("%s: %s setup failed\n", __func__, > cpu_latency_qos_miscdev.name); > > +#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP > + ret = misc_register(&cpu_wakeup_latency_qos_miscdev); > + if (ret < 0) > + pr_err("%s: %s setup failed\n", __func__, > + cpu_wakeup_latency_qos_miscdev.name); > +#endif > + -- Best regards, Dhruva Gole Texas Instruments Incorporated