From nobody Sun Dec 14 21:46:11 2025 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (mail-dm6nam11on2057.outbound.protection.outlook.com [40.107.223.57]) (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 84542184E for ; Mon, 23 Dec 2024 04:36:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.223.57 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734928609; cv=fail; b=pau9oBwj1Wvug46WYWFs3XJh6jEd7d4kFAAckk2NVhUNQqswYWAv6D+60T6h96gLjr8AHgahra+NCQBtqo0q3DW3BUy8IgqGhmnYRC/MY78sNhRRop388l5TbkO3946jqoTQkEIWuykOW6dG6t8MGfyeHnPvY6W4oVq33Xmr2QU= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734928609; c=relaxed/simple; bh=JE9nRtf3RyyDmp2PBCmEv0koJHgp7HQbK/N2b3tfvS4=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nwg0BvSeV10YUukslRMO6VPsQ5/IeZfolPKgzLBJJWiUZKTvBIacehviw9djGhFImMbbkv5HYc62lXyFfyoWqjXP1xN+yDbU9Vj2TXLdSHwV4hwd7SVoGNQTNiynhSJD+Kj17tTjPwmxtNI41OCyjiUbzwirAbu6zmzwoP+4pq4= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=pUXDmfl7; arc=fail smtp.client-ip=40.107.223.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="pUXDmfl7" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BSJiNgyF5f6UcVfJp5oz8qWX2PHPiDNRSkLvss/1OrcQAJdLY0rrRoPcLwjQnS/ncfSIUWKSn/MefALlJ+MEP/wJLUUOzZpPBNV/gxXfqyRi5TSHoOChx+sXCaFSNi58BuNqdKmHw7fCgA0dpmcmmQTEVGFsxW45yvXv7zakTwVl6qtAgnTWE2KfNV22DJ0YMC1X38uVdoEZzAEL2wArvSuBFsmusOdrv4VkvPUzUvYk+FEbRHsRzDaif9hSXGLDrkDWdHUEDsgtlrNCyFxHJVPAGY7h7HVdlVL88sLPPH0Q6bBGo3g0TVEovX6iupLlBWj5t94FGd4nCl5jvg2YXQ== 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=O1n0FntR5SUuVYnusUDPrfXwFdnctkrfFq2ctFLZcVI=; b=tQeYt7MgfDDnL3rAZ42y1VSl1XblL8NpT2V3pF1XYwXIWT3yNQA5p/G0js05SKzy9wtdSAj1GPqSRi1pXXeM/qlDrhAbqFyW50PQ+e6lZJrlgqbVbuZ2o3YTt/6PEZ0A+L0SrxuX2XYNATlqKfkY+XK+3Bu2rA5u/YJwWojBDyZBhHaPQ4T/T5oVG+HCBW3Imo+v5ec5+uicvwteN+Gr4dZ4v3vZFSYB4EcWXOFWojIxGbD/z9OtfKJ4TXFfpJLMgKtI9fAieSkyAgNpMzDi/8FSUzA0CxZvzHodv077o1wkuk/dQTGPaIoeK3PrlqjJHxbdLFInMpjAY7uRTPNBoQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=linutronix.de smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=O1n0FntR5SUuVYnusUDPrfXwFdnctkrfFq2ctFLZcVI=; b=pUXDmfl7lXIdE0gzBc+8F0PJ2DW6q5m5V+hnqrtRAmVi3+xRdzB1PU5D5dy7KnPPlWcVG5yT+QsThWcCavPAHCpND9prwKTAqUuzUtVF5M2jaUmRSSzNL04XNEkZ/zxQcoAw0SimscUEqt2go/td1oV+Dh8Jc35rUruddgDD8oI= Received: from MW4PR03CA0101.namprd03.prod.outlook.com (2603:10b6:303:b7::16) by CY5PR12MB6405.namprd12.prod.outlook.com (2603:10b6:930:3e::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8272.20; Mon, 23 Dec 2024 04:36:39 +0000 Received: from CY4PEPF0000FCC1.namprd03.prod.outlook.com (2603:10b6:303:b7:cafe::9e) by MW4PR03CA0101.outlook.office365.com (2603:10b6:303:b7::16) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8272.17 via Frontend Transport; Mon, 23 Dec 2024 04:36:39 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by CY4PEPF0000FCC1.mail.protection.outlook.com (10.167.242.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8293.12 via Frontend Transport; Mon, 23 Dec 2024 04:36:39 +0000 Received: from BLRKPRNAYAK.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Sun, 22 Dec 2024 22:36:29 -0600 From: K Prateek Nayak To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Peter Zijlstra , Juri Lelli , Vincent Guittot , , CC: "H. Peter Anvin" , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , "Rafael J. Wysocki" , Ricardo Neri , Tim Chen , Shrikanth Hegde , "Mario Limonciello" , Meng Li , Huang Rui , "Gautham R. Shenoy" , "K Prateek Nayak" Subject: [PATCH v2 3/8] x86/itmt: Move the "sched_itmt_enabled" sysctl to debugfs Date: Mon, 23 Dec 2024 04:34:02 +0000 Message-ID: <20241223043407.1611-4-kprateek.nayak@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241223043407.1611-1-kprateek.nayak@amd.com> References: <20241223043407.1611-1-kprateek.nayak@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY4PEPF0000FCC1:EE_|CY5PR12MB6405:EE_ X-MS-Office365-Filtering-Correlation-Id: 742d2ac5-2819-4387-2011-08dd230b6462 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?rqc+vAF4qBVflbBbRRJJMbNrT7v69loExLxRj5Zo1OO2d81/icqYTS/VPCAl?= =?us-ascii?Q?+Edt3r6NQO8Ut2GyKcjC0hy3qidCAAw/0+yL5yTM31NVGY3rnu79s9I2nI0c?= =?us-ascii?Q?oB6PIFd+gASXwP5kPzYYdC0xbTo8+XTENo+pJZAdJEpTbQalxVVKAnhZj2Z6?= =?us-ascii?Q?TSx7EwkzQYccZW+buqEpYnBwFfbUtxq5KHm0cSQdm+eSiT0Z+HufKsjmdyQT?= =?us-ascii?Q?gbT8oVx7PcWpEsUcTs3o7N2GFTEtsmjrEIfURvckj+mkEe2UUhI6n4tU+o56?= =?us-ascii?Q?YRW80clW7v8A1Q1oNf74t0gREBOLYXGuAcLfKtYRRM5MPK0RyN+sWNiqtHRQ?= =?us-ascii?Q?5/z7RwVPuUWXx9kgL84NgTiVqiNv/VTFdKhbvfiJjtjdLmnw3r+yNS8OCNyA?= =?us-ascii?Q?zUW7ifxUFdW8ftv1OsujR55+LjZqHMO2RUopCb8nR+S55WuWY4ZmKABi5obP?= =?us-ascii?Q?3eMq0b8bqe3YJtv55PH9+M5YMfUEOllVtfffE/y+FPgcHC6HoMYYR+TJXjCZ?= =?us-ascii?Q?vl8SZP7I0fzjnfv0guOdXLa68coMZhIr2mvvvxidIC6d7PdGzBogR+njHAIF?= =?us-ascii?Q?YoIO3ZbImatG7F0Uh0vTOgxVab7DYYz/gTqdzsxbILci6TPcFgBft5zj8FG3?= =?us-ascii?Q?U2om5riDnMaSA7oOgTl9o0LQMm2gLo2egTyTIZYWlAQ8PsgDG5bt8DW3cmmZ?= =?us-ascii?Q?mhiPOc3HreHIpMWm5xcwUGdVJLpeEMW0qzQOQ3NK9YcsZte7+bQz9vCjtshD?= =?us-ascii?Q?4C/bo4G/+SqnL+oOjTd3AjObxzuGTnMKF67Ihr7MPqH5xzaMNav9U2sU+/bi?= =?us-ascii?Q?zsZsbUA3iRhp4uitMO/dSOW0A2QXXQ3EfRK+s5XgW7gLBtnZAAXfO6yQm8KJ?= =?us-ascii?Q?CEe7omGPM8SZ2ay848CPUHl2R4HU9Z4RGMZUvFQl/wVWmUv/b8i51ZAN0v1A?= =?us-ascii?Q?7z0Nxf1xQIyoe65+QWTG0Dq5Gosf0MBOv6QzuIg1+yW75N5m4h7IxTrEYjhe?= =?us-ascii?Q?mOAtctLCCSI9RsrHtpdc1bIjdWDM2Yg4MclOL0PaIBAJ80pzfBlLoJBy/eF3?= =?us-ascii?Q?OIq/zaNHN7qm7Y0vRFNHZimnwPkF8D//qML+flIvJPBnTgWOwYvg4aCCPsCc?= =?us-ascii?Q?FFl6cRAdGt87sxngGbcQIKdIKPSmu20GUMMS6JHlY+NhZr4xfZno+lcVIyZ3?= =?us-ascii?Q?M4zuxkdGu+kdGpe7UMFA4DrAR7GF2wMUGeo4M5TnnPDIS8/y3v82HAefBqCQ?= =?us-ascii?Q?Ayu1jkxiPp30KHCpNW21knhz4+K4qr71QaaCCqNyzNG4jQpQosjZNeSdZlEz?= =?us-ascii?Q?SDWpg/9pSq3fT6icDYaDgXLVkC6mwry00EnSjZrNaathIz/xyFjx9gse5gSQ?= =?us-ascii?Q?9ITVUUpr68rx43qoCguCaw80dUQoMqHZJBDAzFQqjbLwGfgzRwtlA7LFBd3f?= =?us-ascii?Q?mHFZRSyanQBMvtXhX7H68LKHmKxF7XjqSDjFUsT0pAhLqdL7K+7pSdpvLXF+?= =?us-ascii?Q?AQ3QMrssCetcGlM=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(1800799024)(376014)(7416014)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Dec 2024 04:36:39.0680 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 742d2ac5-2819-4387-2011-08dd230b6462 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CY4PEPF0000FCC1.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6405 Content-Type: text/plain; charset="utf-8" "sched_itmt_enabled" was only introduced as a debug toggle for any funky ITMT behavior. Move the sysctl controlled from "/proc/sys/kernel/sched_itmt_enabled" to debugfs at "/sys/kernel/debug/x86/sched_itmt_enabled" with a notable change that a cat on the file will return "Y" or "N" instead of "1" or "0" to indicate that feature is enabled or disabled respectively. Either "0" or "N" (or any string that kstrtobool() interprets as false) can be written to the file will disable the feature, and writing either "1" or "Y" (or any string that kstrtobool() interprets as true) will enable it back when the platform supports ITMT ranking. Since ITMT is x86 specific (and PowerPC uses SD_ASYM_PACKING too), the toggle was moved to "/sys/kernel/debug/x86/" as opposed to "/sys/kernel/debug/sched/" Suggested-by: Peter Zijlstra Reviewed-by: Tim Chen Signed-off-by: K Prateek Nayak --- v1..v2: o Collected tags from Tim. o Added a note on how "N"/"1" can be used to disable the feature and "Y"/"1" can re-enable it with added nuances of kstrtobool() (Tim, Peter) --- arch/x86/kernel/itmt.c | 56 ++++++++++++++++++++---------------------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/arch/x86/kernel/itmt.c b/arch/x86/kernel/itmt.c index ee43d1bd41d0..9cea1fc36c18 100644 --- a/arch/x86/kernel/itmt.c +++ b/arch/x86/kernel/itmt.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -34,45 +35,38 @@ static bool __read_mostly sched_itmt_capable; * of higher turbo frequency for cpus supporting Intel Turbo Boost Max * Technology 3.0. * - * It can be set via /proc/sys/kernel/sched_itmt_enabled + * It can be set via /sys/kernel/debug/x86/sched_itmt_enabled */ bool __read_mostly sysctl_sched_itmt_enabled; =20 -static int sched_itmt_update_handler(const struct ctl_table *table, int wr= ite, - void *buffer, size_t *lenp, loff_t *ppos) +static ssize_t sched_itmt_enabled_write(struct file *filp, + const char __user *ubuf, + size_t cnt, loff_t *ppos) { - unsigned int old_sysctl; - int ret; + ssize_t result; + bool orig; =20 guard(mutex)(&itmt_update_mutex); =20 - if (!sched_itmt_capable) - return -EINVAL; - - old_sysctl =3D sysctl_sched_itmt_enabled; - ret =3D proc_dointvec_minmax(table, write, buffer, lenp, ppos); + orig =3D sysctl_sched_itmt_enabled; + result =3D debugfs_write_file_bool(filp, ubuf, cnt, ppos); =20 - if (!ret && write && old_sysctl !=3D sysctl_sched_itmt_enabled) { + if (sysctl_sched_itmt_enabled !=3D orig) { x86_topology_update =3D true; rebuild_sched_domains(); } =20 - return ret; + return result; } =20 -static struct ctl_table itmt_kern_table[] =3D { - { - .procname =3D "sched_itmt_enabled", - .data =3D &sysctl_sched_itmt_enabled, - .maxlen =3D sizeof(unsigned int), - .mode =3D 0644, - .proc_handler =3D sched_itmt_update_handler, - .extra1 =3D SYSCTL_ZERO, - .extra2 =3D SYSCTL_ONE, - }, +static const struct file_operations dfs_sched_itmt_fops =3D { + .read =3D debugfs_read_file_bool, + .write =3D sched_itmt_enabled_write, + .open =3D simple_open, + .llseek =3D default_llseek, }; =20 -static struct ctl_table_header *itmt_sysctl_header; +static struct dentry *dfs_sched_itmt; =20 /** * sched_set_itmt_support() - Indicate platform supports ITMT @@ -98,9 +92,15 @@ int sched_set_itmt_support(void) if (sched_itmt_capable) return 0; =20 - itmt_sysctl_header =3D register_sysctl("kernel", itmt_kern_table); - if (!itmt_sysctl_header) + dfs_sched_itmt =3D debugfs_create_file_unsafe("sched_itmt_enabled", + 0644, + arch_debugfs_dir, + &sysctl_sched_itmt_enabled, + &dfs_sched_itmt_fops); + if (IS_ERR_OR_NULL(dfs_sched_itmt)) { + dfs_sched_itmt =3D NULL; return -ENOMEM; + } =20 sched_itmt_capable =3D true; =20 @@ -131,10 +131,8 @@ void sched_clear_itmt_support(void) =20 sched_itmt_capable =3D false; =20 - if (itmt_sysctl_header) { - unregister_sysctl_table(itmt_sysctl_header); - itmt_sysctl_header =3D NULL; - } + debugfs_remove(dfs_sched_itmt); + dfs_sched_itmt =3D NULL; =20 if (sysctl_sched_itmt_enabled) { /* disable sched_itmt if we are no longer ITMT capable */ --=20 2.43.0