From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2058.outbound.protection.outlook.com [40.107.236.58]) (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 A143C31D39F; Wed, 10 Sep 2025 05:23:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.236.58 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757481794; cv=fail; b=Cl6VGGZUgYcCytxo8ZoeAta8ahJ/Nv6KU6vUUXXKnlQuXLOM6nGl+zVhSn/ytAeUmVWlnzlYfRPJcnCjX4KilJEK7pcJWUJTBGFMdw384ZuTPE0YObzlroshQz2EC5kK4xUskk1zYjWPxSADluun0jnionaaJwCNEzrR7EYV6d8= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757481794; c=relaxed/simple; bh=RIrSzzmzTrXTJ9Ujvzs6WC9eBl23CxiI1KRN5f3dicg=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=QxWjwE/B6uR2p04MHSpQ2Nk5zelxsesqzY6mfeeq5xitkHjubom3NdeQXTirUnR6GguO/DsBNv6sEwSgcUMS0ybdMzGoxM8fl3eoyKSKPgP3m9LDM2OHgUfqm7phf6QEOTHdDmzpNdYTdOFV2FZyBz8s4HLLR3qm5eaKdMv2aDs= 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=ShhnhUE8; arc=fail smtp.client-ip=40.107.236.58 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="ShhnhUE8" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=dvKJKd5HkvSw5A2+E0WdUus9CIz53sE6rKY8hGz5NkATJfysHTD7HdtAOLlbdOGDW9ZyCE5PaSoIprIE6zhPMrIylV5C0UKSjlsAxKn69eJiESXmA+irr/Ts+0j/qfA14m9YtmTwzb9dkuvrbzffm1tmeFfmfFMkpxwrPjnLuYQKFIkGPeqLwVeI1qDBidH6zobsmiJKVBiW1pu/+3K+VV0DhBcZagybWV7rnqIjWMdV3A+qiShVbQ8RjxvmvtcS4zPtmYDcPiJbNHfYtL8BtAO9km2GC9MOd0uWKe101wZ9dVn5OlH6P3JkOnqAdiSZKH6XQU9z264udhqHQTCq1Q== 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=OxMY3cqctP/ebaQP/tRkaJ7pR0Rfe8M3PVOLyTVh+/I=; b=CJWgb0j2bObHIDYGoUcgRaEf1UqSTU6/xf31B2SU1Nlr0hfMPYk0qadorCDtqvlifoJdbgT07Ul/kIy4TYxvAm33D/3Rrxsaz+ef6GeFU4E91BjCNvHhqSqPBOYgo3uODBL7xmtmEQqfk0/aumswFf7K0D6u2qFYMKnZTMozBzbnftXHZ5tYZF1OBuewS5j4i+XKTYCne9lNr369fQmA8Rh7OlCJaDby2UIQuZtLxOjjI578SnmuI+3Q0dSHAn1L2Mxo9A8Wp+T0l8JyVqUyj5YjmuSAYrdXOCt1Eb4uEGNFFPA2Z47WzBC9FHzIWT4aXnwzTKPqQTYTVP4OxjIVKQ== 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=OxMY3cqctP/ebaQP/tRkaJ7pR0Rfe8M3PVOLyTVh+/I=; b=ShhnhUE84YBg/ZtgXi9zw1WHsRC9DL3StGtyBBVRoRVlzXPiYuy5GkpE1ofk2KyG9e76MPBYfEaszhed1DpaJiegeCR0Avew6Xz+LhHbOE6kz1JnPIQ+J5CyPVm1zPD0FhXIMkzGQBDwLgcEE5YQxH6pxqTd9BXGUNWsRxvLo9Q= Received: from MN0P220CA0029.NAMP220.PROD.OUTLOOK.COM (2603:10b6:208:52e::9) by IA0PR12MB8894.namprd12.prod.outlook.com (2603:10b6:208:483::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9094.22; Wed, 10 Sep 2025 05:23:09 +0000 Received: from BN1PEPF0000468E.namprd05.prod.outlook.com (2603:10b6:208:52e:cafe::bd) by MN0P220CA0029.outlook.office365.com (2603:10b6:208:52e::9) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9094.22 via Frontend Transport; Wed, 10 Sep 2025 05:23:09 +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=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BN1PEPF0000468E.mail.protection.outlook.com (10.167.243.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9115.13 via Frontend Transport; Wed, 10 Sep 2025 05:23:09 +0000 Received: from satlexmb07.amd.com (10.181.42.216) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Tue, 9 Sep 2025 22:22:55 -0700 Received: from [10.85.34.232] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Tue, 9 Sep 2025 22:22:51 -0700 Message-ID: <45b4a0db-dab6-4b9d-9ee8-f564eaa202bf@amd.com> Date: Wed, 10 Sep 2025 10:52:50 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [patch 07/12] rseq: Implement syscall entry work for time slice extensions To: Thomas Gleixner , LKML CC: Peter Zijlstra , Mathieu Desnoyers , "Paul E. McKenney" , Boqun Feng , Jonathan Corbet , Prakash Sangappa , Madadi Vineeth Reddy , Steven Rostedt , Sebastian Andrzej Siewior , Arnd Bergmann , References: <20250908225709.144709889@linutronix.de> <20250908225753.012514970@linutronix.de> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250908225753.012514970@linutronix.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN1PEPF0000468E:EE_|IA0PR12MB8894:EE_ X-MS-Office365-Filtering-Correlation-Id: 3930a424-150b-4981-b01b-08ddf02a212b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|376014|1800799024|36860700013; X-Microsoft-Antispam-Message-Info: =?utf-8?B?b0RRc0hoZHNXNTVjMkZ0bGFlRm04Qy85ckhLTER4OHkvWmRCNU1UMjhvM053?= =?utf-8?B?NzNaNEd1UytpalE3MC9pK1JtTEZ6VlNlTVFTRG9STUV2TWR6ZmpPRm1DTVdj?= =?utf-8?B?aXBvNUhyaElsSVNJWlZvZGNmMTZzR0xhYk1hc2ZRQVhZVnh0d2RkdVR0aTI2?= =?utf-8?B?V0dpelF0UXZFb2NMZDBOV08wWmNPbGFaQktyZlNFV2kzRVJHM2FmUzhEYXIz?= =?utf-8?B?REJ6QXhjcFlKUUx2VzlvMXFGc0EyTTZWK1AxTThmMVc2TkpkbHlpd3lOSVND?= =?utf-8?B?Mm8rb3V6WThrL2RlanlycHVodHR4dlJqL0hnTHJscGovQUxNOSs4dDBrNkMw?= =?utf-8?B?bVQzR0pFd1JTdWtOdFRWN2U5V0Fac3ZkTG5UZ0Y0UjZ2REpHT3JZMlJVaERu?= =?utf-8?B?TGNmQTgwL1gxRHl5UUVkT3g0QkxBeUZJaE9RaW1XalFUbzIrTzl6UnBwV25u?= =?utf-8?B?MEswR0JrU0Y4WlpNWU1KME1hWDZBNXg4cnpCS0NVRXBzdWRLWDJhcG1Td1pp?= =?utf-8?B?Ull0UUhUQzEycGpRVFE1WFplbDROY3FFclpQamc0Q1hDemVtOTUyNUZyOWJw?= =?utf-8?B?V1psdDczNG92a2VWSDlEQkJBWVBqYVJKSFhObUJ1K0I2REIvVDAxTmpjdkQy?= =?utf-8?B?ZkdXYU9EbGkySjBpNVdkWmcwUEZzSU9rYSs4dXZ2YlRuTmZZa0tKS20ra0N5?= =?utf-8?B?bXo5Uzc2RFBWb2d2b1hXc3RCaGRiZTlrcnJIM1VGdEJjeU9Ndms0akh0RUpQ?= =?utf-8?B?ai9xZ0JwcWZjNVFyaXFTNWxjSFB0eGtzdDdlV2JrK0srUWNtNUVaSk1yM0Yv?= =?utf-8?B?N294amRDc203UGRZM0wvY0JzMmtJV2FvL044M0hJMXkwRVVpdmEyYlpCMjRn?= =?utf-8?B?RkZ1QTc3bmRoZWpWYll2SmNGRzk3QloxUk1QYXVITTczQzV4L3RaNkV2aDQ4?= =?utf-8?B?T0pPSUFUeW5hWWt0cHNtb3YydzUyRmdEb2g4MnQ1SHJlaWhkeU4vQnR5Ym52?= =?utf-8?B?ZlVDZVRQQ2syNGYyVkdLNk5ZRFFtU3ludWR3bG1WdE5ZQ2poZGs3eGRwdHpa?= =?utf-8?B?eHJaZjJvNi8rOTE0N2dDWlVOYU04WWR1S3p0cU5odWNFWkczalhoc1JtNG5P?= =?utf-8?B?RE5jRUE5dnR6NnhtOWRuU3VHemY5NGh2b3JPQk9HTzQxYkl5QWQxeGJXdkkx?= =?utf-8?B?dFc1OERYWVhmUVVaV0dwMnFkd3VaUG9oa0NjVU9DWUYyYk1sTVdVOTFDcThh?= =?utf-8?B?WitWTlZ6ZHhtOWpMK0NWUldGNkFIRUFzbkJieU9DWGc4eG42UWEwTmZHVmpH?= =?utf-8?B?cFNtUWQ4YUZPU3RIV3hPNXByN1EyeEFlTkRBK0RUbTh4d2Fib0NsSWU4S1ZW?= =?utf-8?B?RlZCNWx1QytueU5vb1YreUxLZk95NVgzbzg4WTZJOXZvd2dsRE1odExWajVr?= =?utf-8?B?TGpTR3lIS1BTZlN4TnluZWJqTVNKMnFkTGZpSENYVFY0eDBjOFRRMEtxVkFl?= =?utf-8?B?WlBWa1ZuODdlR05WeHVFdzkrZFRqQkN1dmVZTktwSGgzcC9JS1lpV29KTk5C?= =?utf-8?B?VVBqSXVMWTM5N3Y2YWZxWjcxaVBNYkpBV016VCs3RWtFYmI5N0d6aFFtUzd1?= =?utf-8?B?ZnlLR3VGa2M3cW5zTXNEclFtUlcxbEVIeCtpaDZjek5BWm9MR2FyZjE1QlQx?= =?utf-8?B?UnVzdFZ3d3N1OU8wMmFZVkRMTk4rWmdOSHRKaytzQ1ZpS0pDTFpWekwwSXhR?= =?utf-8?B?V1p3WTJNY2Y5ZmJxRkpPQ2lPMm9qUkx0VlRYdEpUcDlCOENrS3ZBSmltaHVB?= =?utf-8?B?ak1xdDlGTU1qWFprQkZ1cFpHSWpBS0FIRy9TZnJPMjBRZDVpZ0FlbWdpYkdN?= =?utf-8?B?bWR0V0NlL2MrZUl0UDZ4cmFOdy9lcGJyKzdZL3BPekJSWGdERzBucVJ6VnhO?= =?utf-8?B?Uld1SENSSzdLdldON05zNlRvU0s5aFllM1JyZVZ5NFJoOHJyT25SK3VhaVl0?= =?utf-8?B?UVplYm5RWTdTdDg2U2haMEtLbXVlSWxtcnUwVS83MDFTTlVrK3lsdVBXNktm?= =?utf-8?Q?9Ai7Mo?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(7416014)(376014)(1800799024)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Sep 2025 05:23:09.1861 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 3930a424-150b-4981-b01b-08ddf02a212b 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=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF0000468E.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR12MB8894 Hello Thomas, On 9/9/2025 4:30 AM, Thomas Gleixner wrote: > +static inline void rseq_slice_set_need_resched(struct task_struct *curr) > +{ > + /* > + * The interrupt guard is required to prevent inconsistent state in > + * this case: > + * > + * set_tsk_need_resched() > + * --> Interrupt > + * wakeup() > + * set_tsk_need_resched() > + * set_preempt_need_resched() > + * schedule_on_return() > + * clear_tsk_need_resched() > + * clear_preempt_need_resched() > + * set_preempt_need_resched() <- Inconsistent state > + * > + * This is safe vs. a remote set of TIF_NEED_RESCHED because that > + * only sets the already set bit and does not create inconsistent > + * state. > + */ > + scoped_guard(irq) > + set_need_resched_current(); nit. any specific reason for using a scoped_guard() instead of just a guard() here (and in rseq_cancel_slice_extension_timer()) other than to prominently highlight what is being guarded? > +} -- Thanks and Regards, Prateek