From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=40.93.198.62 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1794599285; b=HQs1C57/f3embjll0VJeDFJZfhDKZjHFb/nXphqD2Y16NvpilK+ui/DKYR/ixtck3QXU HZ9UDRBi/PeIf229MAOiTbf5EUMGNLe5xS+9gYGWolzJtA9uVGmF7Deny7x9zVIagSPbc GUvNlT7YzpExC60uVCt/QiM/N4iObyUb5JRrL5/fgMCIreKgk6Pnx3JI839bu8VgUjiqG CPijal6Hqbz0uq6Z1hmErGIbYjEFGtW9Kk3uuhbp2TX+YB6Bgin0lR2HO2V0WGAUiX+9d BJSJMrHU1rGRBTB4HmLi2SjCVChFs+lhguYX+KJrEvsa4ez0EodYvR19nci+vmVHEHQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794599285; h=DMARC-Filter:DKIM-Signature:Received:Received:From:To:Cc:Subject: Date:Message-ID:X-Mailer:Content-Type:Content-Transfer-Encoding: X-ClientProxiedBy:MIME-Version:X-MS-PublicTrafficType: X-MS-TrafficTypeDiagnostic:X-MS-Office365-Filtering-Correlation-Id: X-MS-Exchange-SenderADCheck:X-MS-Exchange-AntiSpam-Relay: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-OriginatorOrg: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped; bh=572P3fs5L0aE2ZBUX2LGTjefHmWDETaMk+vg+KJRZO0=; b=Ky3yTvZQWAyVBnj/y3w47LcVQyZWYeJdYXOK3NCNMsg1Gt6YgS/142W7TZwySsuPbMft cKuZrJZNLnB59CwNK3UX2h1zX2AzJPV8nJF3pS/WCG5rrelCc/04qWdM32zj27p+iaGm6 +qT5lsrRiIDe4LNJ/1I5y/9G2YSfLfH2UVllHM9kc3hVybaqVFPurK8pYLjwSdlSX9PSQ riuEcylTPr27N21PgTbBSdNR9T4o2yDyumn0dy2W/OV/s0qBYSwG/5RZCY2bci5eGrGl1 XUsxCmHN1QYO/iwnX70RbQEPnN7SYragUBTfFQAx2Ev9Vivgj7IPeXhg9bgf4wK7PZw== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b=Pd8RlUwP; arc=pass header.oldest-pass=0 smtp.remote-ip=40.93.198.62 Received: from CY7PR03CU001.outbound.protection.outlook.com (mail-westcentralusazon11010062.outbound.protection.outlook.com [40.93.198.62]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (secp384r1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 039C9606A88E; Fri, 13 Nov 2026 19:48:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 039C9606A88E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b=Pd8RlUwP ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=I97rdz2/8eLviVcryU8iPnEWgh6FDjey1k0ZFcG33rWcUzVKSmbgHY56s1ytq8xDRKEKrEsutKxUX7eQzaZz8iPMcm/xV2urXNyju0cP8B81gaZepWjsylrliB7GqsCxk14+XNdmX1zheFXapjbkhIt+OOlm1f7fjKCiyx5FR06qFnQadXZfGwS6vGc1oX/DHR0QN3psGA473n5i/Y1eVohb1oeNt5oW5NzYSPtA1qF+FfrdGgMcL8zXOI4hS8gE1CPpcSzqm4AsnpqUU27QS5poMbRwpdobMHW6H6YtKUuH6eCW7IpuPLi2Vxc6Bv1nV7KD1/kk/FJDMpCW5NTGFQ== 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=572P3fs5L0aE2ZBUX2LGTjefHmWDETaMk+vg+KJRZO0=; b=mogZ59RUyY6WSXr4bf6wdHGWuNsnOb9SFoWolq247ZQFfTjhnVrMe4VKr34PY+wEOpYlYr7Xd36lvU4qoT8JH0+riInMu6PvTnEZomlWLvX4knGPQnksRRev4yMxyDO0KxAHyUndls0qdDAw90K951/jkeKLVo4Sx1C3VmuhydIRl3lbtRSiGycLoaIFZUJuWrnImWae0znOx6mD85WBZ2wnd1kPuUGRX9dWb828XAomVLTAf23Ag0hO7g/7WQ59/17uIIPnIx3l7gAARiTeOxFDyh9WBXYJmZvT/7APUGHM4flgwiiU7R+gGN3dqOS1oCgdh19O9BGqR+Mhivo/UQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=572P3fs5L0aE2ZBUX2LGTjefHmWDETaMk+vg+KJRZO0=; b=Pd8RlUwPBW9tNBxrO5cpv/u6SOjLnanPsbQ+VJNr0LpqK3gK5uLWuh/dk1vNHUI8AXfUvMIoaSPRHXmofopQwh4hJtVH0wYuGvWyBQRx/K46pMHA+orod/aAZ+JfdMNwebTrGjSSsuMa90SgDSKxwAm9zXV4OhovIpa0DoFgraF/ifXDjdeaNzeUft2NUjLIomhUg3ID7yM4k3vnwTqaACVz5ycrE8+8HiHDlMHBFIUSX6ZxX9txkk2CsEgwdi0LGsgX1kld2iyfBoXNLK5Jr4HDC2DhZWCGvBsg/kdHdTw8WFEZKLdbxBIhEJ0WiaTwFnZBJF30hn6bFqMQ7fsGeQ== Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV3PR12MB9356.namprd12.prod.outlook.com (2603:10b6:408:20c::21) by LV2PR12MB5896.namprd12.prod.outlook.com (2603:10b6:408:172::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.592.11; Fri, 13 Nov 2026 18:42:59 +0000 Received: from LV3PR12MB9356.namprd12.prod.outlook.com ([fe80::1c36:31b4:c420:6286]) by LV3PR12MB9356.namprd12.prod.outlook.com ([fe80::1c36:31b4:c420:6286%4]) with mapi id 15.21.0615.007; Fri, 13 Nov 2026 18:42:59 +0000 From: Yury Norov To: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Juri Lelli , Vincent Guittot , Shrikanth Hegde Cc: Yury Norov , Yury Norov , "Rafael J. Wysocki" , Alexander Gordeev , Andrea Righi , Ben Segall , Christian Borntraeger , Danilo Krummrich , Dietmar Eggemann , Greg Kroah-Hartman , Heiko Carstens , Ilya Leoshkevich , Johan Hovold , Jonathan Corbet , K Prateek Nayak , Maxim Kuvyrkov , Mel Gorman , Mete Durlu , Randy Dunlap , Rasmus Villemoes , Shuah Khan , Steven Rostedt , Sven Schnelle , Valentin Schneider , Vasily Gorbik , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, driver-core@lists.linux.dev, linux-s390@vger.kernel.org Subject: [PATCH 0/7] Harden preferred CPUs management Date: Fri, 13 Nov 2026 13:42:49 -0500 Message-ID: <20261113184257.621707-1-ynorov@nvidia.com> X-Mailer: git-send-email 2.53.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: BL1PR13CA0186.namprd13.prod.outlook.com (2603:10b6:208:2be::11) To LV3PR12MB9356.namprd12.prod.outlook.com (2603:10b6:408:20c::21) X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV3PR12MB9356:EE_|LV2PR12MB5896:EE_ X-MS-Office365-Filtering-Correlation-Id: 99d6f12b-b426-4047-01e1-08df41b5f0dd X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|23010399003|366016|1800799024|10070799003|10067099003|261022105027099003|261021123027099003|56012099006|261026140227099003|261028144727099003|261102123227099003|11063799006|261009223027099003|261021121427099003|261022075727099003|261026121527099003|18002099003|3023799007; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV3PR12MB9356.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(23010399003)(366016)(1800799024)(10070799003)(10067099003)(261022105027099003)(261021123027099003)(56012099006)(261026140227099003)(261028144727099003)(261102123227099003)(11063799006)(261009223027099003)(261021121427099003)(261022075727099003)(261026121527099003)(18002099003)(3023799007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?aGdUeWxCbncrZmo5U1lBTjJRKzNvZTJEK0d2VHVwZGNhR0hwSkxuM3pueVRp?= =?utf-8?B?WnRlNlhOZFNhVStzZ1ZSMUZGbUoxdzRpU3h6SFU1dHdlOWJoNUp1Vi9BeWFk?= =?utf-8?B?RHZpdHliTFF3bEZFSG5Ed0djTFhLdlNCeTZ3QVp3aGVFRnNEdVpEOHJqalIz?= =?utf-8?B?RkdNbERpamMrUTUwUlBFNnlDSHBIRTVUZTBjSkt0NS9hVzY3dWtmN3hpZHhH?= =?utf-8?B?dlMvWUpsZlZmQVRScHNyNkZqTEd1OGJkUHZhZ1AxVE4xUkdpaS9QT3FkR2hW?= =?utf-8?B?cG5DQ1hoU3JCa2oyZmt5amc1ZncrSTNIMFkxTURYaTZmbmVsUW1seGwzZ2Zt?= =?utf-8?B?dVZQVkpuR2xJOU1EcjdTQUVHdHFFWGUxMUNkdXJGUlhmRTFjWC8wdW1RZXUz?= =?utf-8?B?dVhoWW02cm9PNWJSMmJRQTJzZ3JvZURCbkcrRStHNzh3bWZLRGVMR3JYWDZ5?= =?utf-8?B?RjlMOXVENjV5VkhpdkNhbkg3angxWmkyVzNTTkovcUlwb0pCM1Y1RzErTERV?= =?utf-8?B?OEJVQzMrRGZhME5OdC9mR1FDRU1BSXQzWnpFZ013RzM0ZGEvTjdTaVgzWlhn?= =?utf-8?B?em9TOFVPMTJnNEtYdjl2a3Q5cDFjSXd0MjVRYjRTeDZSZzhnaEZ6UkhhaUp5?= =?utf-8?B?R01BdTBaS0psSzViU01vcE1FVUtOb2QyV05JWWJlUWxJRUx6bjEwUEdIRXJV?= =?utf-8?B?UWx3NjRUVnhFSmM0NE9lU1NFY0JZVlR4WDBTQUFHLzEyMVRwN2Q3bytJQUh4?= =?utf-8?B?MWtJc2ZpdGZkUXFtd0NqaEpwcU1UbW1TSnRtV1h4NGk0SHhjclo0dXU1MlZ0?= =?utf-8?B?Vkk1VVpPVjU4dzczdlBFYm11VU5KWGpFQi9NenladWNCVkpnOFRERzhWR2Nx?= =?utf-8?B?TnRXd2diY2l2UFlGNWRDS3ZpQnNyamlES3VKenBDdSs1L0l6bTQyRDFKL3gw?= =?utf-8?B?cnBKS2NTb0RCMzVvTUMvVGdUUk53N3h5dHJYYVJiVnBFa1VycTkySDRFdjU3?= =?utf-8?B?UFJ6WHBITjM2dnBHTkUzaGFxd0xsNWpkcEFzbGJEcjFFb0pzZGFWSnRzamw1?= =?utf-8?B?blhBWE9aTHBRRW5PZGVybG41MXRKNENWU3d3cXlJamlHVy9qdGJOVTE0TS9W?= =?utf-8?B?Ymc2d2luYnBvbVg0eUFwWnhkSEtkS1I3aWVLSjMwYTBXVWlTN1Fyb1FqYURH?= =?utf-8?B?ZjZtdXgvWCtWb0tiOTJBRlJjUDErTjZXVWpjcUo1dkxWVm5ZWTlNMjRERlFY?= =?utf-8?B?akNtOTNBZHhGb3VacXlYZzVZMWtpWXp6UUdBbCt1ZzhGbVdMdVNjeS9lODh1?= =?utf-8?B?YWNZQjVPZ21UY0N1K0V1ZUMzTy9BRlE0WkVxczV2QnJ0Mmt4WmRISHozdUFU?= =?utf-8?B?OERMcEpFOG4xR0xYWXpBK1E3Tm5BT0krT2F5Y2xpeitRdExWenEvNytualJU?= =?utf-8?B?WTU2QmxoVHBDdkJFZXdKNWdnSUJrQk9LcHZEdFVFc0NqcGlYRnBsRDY2cmtk?= =?utf-8?B?Vy8veTFKa0NtZkgvSFRMcXc1c0tGWURqeFJRTSsrSzV0NVZqc0RQZm9Qd1Ur?= =?utf-8?B?dDdxblhVTjZZb21WQ0k4VGNzRkRVdUEzWld5eDEveDFZNnJTTG9KWWNYNlNU?= =?utf-8?B?VmE3RmZiMytyKzh5a2dZdUdMUU80bHVzdytGRGcyWktYZStqSmltaGNpK0Mw?= =?utf-8?B?ajlkRnF0cVRtaU5YU1FzWWlsYkt1WlNMYnExdStTemE3M0NvdnJzdGVyV0Q1?= =?utf-8?B?SnoxM2RXdWVyTmlkN0xxMnJSQU1sZzZzb1JwOUlIYi9Qa1dYRlNuUm9rM2ox?= =?utf-8?B?OTFyaE9iM0dZcmg4ZFFBa25NeW05Z1JuMjhQa1pYUGRxVndKRnlWd1NybXkw?= =?utf-8?B?TjhXZTNlU0dEMjNEb3hRbmpCSDQ2b0JwbEhUSWMzN3kvcExKUWRpc0hXRVVG?= =?utf-8?B?K2dlVWVXNm9XN1ZGRm96MmhiWFpvbGhXVUw2ZTAzZitINzdTZDhqeWdUclFh?= =?utf-8?B?UnlhbVFKYkpBMzV5cG9GaUNxZUNEK0d1ekpmY2lZa0pHUE9KUUcrcGlQc0gx?= =?utf-8?B?MXhZWXFweGdOc3VMZTFXOU5UblFmRGNhY3NkTFVQZG9sVXMrOHFCbmxHL1Bk?= =?utf-8?B?MFkwUjBUaGorclpSMGczelJTbWRrWngweHlBUkErMzI0Rm0vR2lzSDlhS1BL?= =?utf-8?B?L1ZEZzdmbzhNSWwwTUlwK25maDcwVys5VlpXVTZ4aGZoalJsR05mMS9Yb1or?= =?utf-8?B?aGdwbTZGeVlDUks5NHRjdTNwbEgrM2JJUWh5bEV1OUVMTW1nakJJSjZ2NGpt?= =?utf-8?B?YzBveGhRTVUzeWVLblBZc3RFeWRDZDQ1THp2VVZ2VjZ5NDhycHRMVS9Wa0V4?= =?utf-8?Q?yq7sav6XAqAEcHjSSHAZz/p7mEuoYHdUxj7Qu?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 99d6f12b-b426-4047-01e1-08df41b5f0dd X-MS-Exchange-CrossTenant-AuthSource: LV3PR12MB9356.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Nov 2026 18:42:59.6982 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: pX9RMNz3+Xx0ykwItLox5/2VEKTHwtGTgREsdTKEN803cwk/sijaxkJG0DWrbVbz76Z5+aEzKPL6UdNB2Stfxg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV2PR12MB5896 On top of tip sched/core. This series hardens preferred CPU mask management against CPU hotplug and prevents competing governors from overriding each other’s selections. This is partially a resend of [1], excluding the write access, and partially the new material. The write access to the preferred cpumask is a subject of the ongoing discussion. I'll submit it as a follow up shortly. [1] https://lore.kernel.org/all/20261101192203.6979-1-ynorov@nvidia.com/ Yury Norov (7): cpumask: add reset_preferred_cpumask() helper sched: restore preferred CPUs when hotplug removes the last one virt: steal_governor: remove the minimum elapsed-time check virt: steal_governor: serialize sampling against CPU hotplug virt: steal_governor: warn on unexpected preferred mask states virt: steal_governor: restart sampling immediately after CPU hotplug cpu: make preferred CPU policy writers mutually exclusive Documentation/scheduler/sched-paravirt.rst | 2 +- drivers/virt/steal_governor.c | 82 +++++++++++++++------- include/linux/cpumask.h | 30 ++++++++ kernel/sched/core.c | 8 +++ lib/cpumask.c | 67 ++++++++++++++++++ 5 files changed, 164 insertions(+), 25 deletions(-) -- 2.53.0