From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from LO2P265CU024.outbound.protection.outlook.com (mail-uksouthazon11021073.outbound.protection.outlook.com [52.101.95.73]) (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 160E53793CC; Wed, 20 May 2026 21:50:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.95.73 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779313841; cv=fail; b=M3wmoa0CSEuO5A2vJ7SPxj0mlBd4ITOpFK77fPuOSEXEY/kPHT+RNtnlVX1MAp+EX+b6q3bF+Y4ldIIoloD7D4D9LelBQpr1H6TgKMZIJskG4AdG7rjlFv14c9tDKibbTnZxfk+aM4sRDpNQUyAucVqjtc5wz5X6bD90VmF6gSE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779313841; c=relaxed/simple; bh=UWFhq/2kL3lnPgDi4dhRNKnTTyNwz8PhGPr4C9Np9XY=; h=From:To:Cc:Subject:Date:Message-ID:Content-Type:MIME-Version; b=Ij3oY8m2XxbHqvhuZ/tHIkrD2hJIbq+JqtaFnYSTEHMULtKGzwfdNapWB7EdXcdotJwstZr8cBL/5HVes/7FrxpZ3+85T6QGKzeGWa9IslXm+xwsUkovzi50tZNVvdc7GCK3uEgFqwstvY+qL27UcgtO76qSMtGn2A5U9F/MWMY= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=atomlin.com; spf=pass smtp.mailfrom=atomlin.com; arc=fail smtp.client-ip=52.101.95.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=atomlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=atomlin.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=f6jeI+qDJtvppj/dUITikspdM7GSla6T/QZ4BrUG3Ve1yrGqE3aGTBQKvER8gl8KE06JMrusjabopaYTyF4s/f5kH35KGk0mjH0R7cK8VFr++i7/Ixzd/TC6NWepHqq16V0ZHKLiJW9YSrMyTTNKPeCcfQ0Ayal+VpofTFEeJyY7cbUFHUXs81HeZ0P4p41pMPAiLOcI2n/3T+LsLlYTpcHKDKBioUIX5+OT0qa4vM2SvmUC8fLIzJDzn3FKgzAELuR13qvItX3ciuQnIpJzfmY23D5u9KAbE0bl4YcX6T+Gh3PjtSHquemGg4a6pyST8mpWf81i/EDEIaFSO1Py8Q== 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=xIKexwYWA9ekxU2w63RZmw4uHzsQB2YSMNUJELNLgYo=; b=enVrBPPZed9bU3uBcRSoqPv+kESn98c10BWVkboUmqR7GyM2KHIvRCh7PckMpX7FAFpos6wxrw4AOvkmU2zxLq5RruYgGsEWJWDo1z8uNgoIt4wl0SBrxalnyC1drMS7Z0+9F8SBhDTHaWd43cqFJUPOyYyrYGPky7HNmBuc3MkIyr5SgBh5qf5N2Rca9gVSgp7ipT+rMO6XLzN16G+6TaweFvI1tihqqDxAp+HAEJ/NSic088Jo5mydYJ/7BWrLE9HA5t6bYqcD1j/UW8PKGiRPhEK/qBDdqz9lj7QwRjFxudJroUcVvYwT5wDg9siVv0ZrycUdnI2I/hVeaq4QnQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=atomlin.com; dmarc=pass action=none header.from=atomlin.com; dkim=pass header.d=atomlin.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=atomlin.com; Received: from CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM (2603:10a6:400:70::10) by LO4P123MB6626.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:278::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.48.16; Wed, 20 May 2026 21:50:35 +0000 Received: from CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM ([fe80::de8e:2e4f:6c6:f3bf]) by CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM ([fe80::de8e:2e4f:6c6:f3bf%2]) with mapi id 15.20.9846.025; Wed, 20 May 2026 21:50:34 +0000 From: Aaron Tomlin To: axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, mst@redhat.com Cc: atomlin@atomlin.com, aacraid@microsemi.com, James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, liyihang9@h-partners.com, kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com, chandrakanth.patil@broadcom.com, sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, suganath-prabu.subramani@broadcom.com, ranjan.kumar@broadcom.com, jinpu.wang@cloud.ionos.com, tglx@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, akpm@linux-foundation.org, maz@kernel.org, ruanjinjie@huawei.com, bigeasy@linutronix.de, yphbchou0911@gmail.com, wagi@kernel.org, frederic@kernel.org, longman@redhat.com, chenridong@huawei.com, hare@suse.de, kch@nvidia.com, ming.lei@redhat.com, tom.leiming@gmail.com, steve@abita.co, sean@ashe.io, chjohnst@gmail.com, neelx@suse.com, mproche@gmail.com, nick.lange@gmail.com, marco.crivellari@suse.com, rishil1999@outlook.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v14 0/8] blk: honor isolcpus configuration Date: Wed, 20 May 2026 17:50:22 -0400 Message-ID: <20260520215030.496803-1-atomlin@atomlin.com> X-Mailer: git-send-email 2.51.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: BLAPR03CA0083.namprd03.prod.outlook.com (2603:10b6:208:329::28) To CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM (2603:10a6:400:70::10) Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CWLP123MB3523:EE_|LO4P123MB6626:EE_ X-MS-Office365-Filtering-Correlation-Id: e0912188-bf26-47a0-9c00-08deb6b9d1fa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|6133799003|5023799004|56012099003|18002099003|3023799007; X-Microsoft-Antispam-Message-Info: /s5Dr6YIPSbu+YH8gTqIo/uKMHQ5AIkiJ/xJudADBZcqfS73uO6W3tSZzvlLezkwSIan8ef7qHj8DAs5mvT85swHoFJ3UmTZGDyM1Z61CkCpAaSTkBtwmC0WR1xxD95YOpDI1yuGdRqGSz5l7XwsPwyBIE2IslSQfVm3e86xstyJ76f1geHhCJVXWvFpdcndf/rMFOq78ufcWBOAkvelOFHit9s+Mr7PYEcla1UTNhs2CvGmPA6HhqDlaLeQdSlQ3LO8TyuXxA65YxXfeG0LtNenKWwZoGiBPyb0E2uckuhYQCg83Lg4D1iEn8MGf/BvasfdoKReoHENbaIYR2Zhyn+/Bni7E45wKTfx9KxPdjB48aOJU8YbuYS3mP/gzgyqnrOoVxRBFvyfrnO8OD/tky5Q9PNK/j6Ccr7AvNm9SIhypHHpvPCJECQTd1PnqsQHA4lSFLOq8H8qN5RgQn0mlRouf6FrAMXAGtaZ+qzmt6+eAMpEeptRcA49mjMiz+lzuIJzCQyPSqgl7c0jITzNQXnsrLXRLwAmffKS+8ta8KB0eL960Q+9cu2UOa4PbjBaHS/D3pIa/ZZTUps+oyYLgLgHVS8nl+y8NxjNYS61HPEzYPmmYEEhbvZgZ8EQ97OdiDktLfDqVgRLBsL7w4C8bw== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(6133799003)(5023799004)(56012099003)(18002099003)(3023799007);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?BlwO8PQMdDcAd8xIRVQqWM6cTdaH6U59lDtrPM6ye3sbgOT/ESGVI3gqVyX2?= =?us-ascii?Q?XQAUwC59iOe6OWg2rzrQKcxSkGaFB0rjRvWh/1qQ15JmvU15pn80P0ACDq6V?= =?us-ascii?Q?lxBRKZY27V+zN5vh9xT8Ln/rx1Z13l61qwwbu9DmPChEtqtGun/dvFywdajK?= =?us-ascii?Q?zREgn1GN3fZuvHfBSma5mI09P83bA6g0dBqhX8c7QP+13InQwRHQBuUWAU66?= =?us-ascii?Q?53L9nXywamaBLrDbDILt9qFZGnwovf6foXToboCUr0l9E0PQZfybtnr4RxDO?= =?us-ascii?Q?SvS8NizAYQ0f1SajJBUqlR4e8ZAE3wfhxqlGmHzFFaOM4SCPilh84l/t58Ji?= =?us-ascii?Q?28YQ9+qH3UaaN0GYXzvYz049lx0FVQkLW2dyG7Tg94R5A3U51ZKGp2x2wuq2?= =?us-ascii?Q?JsWWE6yZ7/dTKvSOyrTrkvVaqNPl/CtWpsKsQsdymz8Ie24UMnAw5BSvSGVR?= =?us-ascii?Q?+gL+8IgpYczUuB2Ft6S/uC25nGEzM6qJ+IhmBEPr0FirAnV5awf63uZAPuAp?= =?us-ascii?Q?mwEOQPCJdGW6SS4rhMFQkxTeAg5yhmdgC+KkC1PiQ/2N7ki/b6RJ0r1fV48/?= =?us-ascii?Q?DkE23rH65LURZRl0fErWbbSUJRooJisUyHtp6uryi0xGNK79dp/4PKtOF12E?= =?us-ascii?Q?be/gecAWRrRXF0+Z7gXFi6p0KnoF2tz4E7NlWmROlvAg+KXJivMSTH+glxmF?= =?us-ascii?Q?6WAsHlPYv10mg7s33EVHYQZaW8CJDzi5YslJG5LR5i/tlyqhkXSt9Y5AVwAB?= =?us-ascii?Q?ZRQaPwQTqecj1RxP5tkpbxEGu3a5sKvfnoZv6ghgYz2wLZx/MZBhojtBUW+M?= =?us-ascii?Q?N8IR0ur63jlZEt0CLG9rRIk6nCQ1d5Zc/naKWIMBuy07DyjgXugGn27EG+gS?= =?us-ascii?Q?SUWo7hWkOhV7lY6ULj+kEYLQdchLkqpbPgkhruc3r8Nv7aIZEj/dvT6MCXTd?= =?us-ascii?Q?GzgC/OcFVjgSWGhAkIsnRsekO4/J/c5Zt/ZHyBuhEhKZXC8yOBkTFvMJQxL7?= =?us-ascii?Q?Su9HFamaKKCryhvuZ2/EG9ZSwJYzmgfamOqQEnZ8Ydk6NkiEwmMmU7u2Ds6r?= =?us-ascii?Q?GPzUKPp3prYGTiCPkRDsJzUg6IZykVmhzF8C16L2aZvpyMuAFxp3V1NMp3+E?= =?us-ascii?Q?Za+9YmfRG72D/g14AUpmFrQ8TtqYirsXBfvMs1CWuxdTUAMkDoVHoVkAitIJ?= =?us-ascii?Q?veytd8nfV9wwZ79ld2qZWm8Q7hXSwu0iG8bsgn4KbtbPeQm6nF1z4YSSTcmW?= =?us-ascii?Q?4d5Tb+ANEyLNEF41mqvG74IAVaC2KlT7wxWOnM4q5VQV1Nfbt9i6olwkBOJx?= =?us-ascii?Q?H/iRMk1x/pxMdfmAX/8KUO87Bm2t6qIOjz6BGqpy4dd/h9nxTY0rkdS7C5qb?= =?us-ascii?Q?fl0YSi1F9yv0JRU1ym5oXWaPVdZMdzrNGbrEt2CdNvRUq78TnN3DwZGrjy1B?= =?us-ascii?Q?BOvABlSXZV4S82vKJfbf/+2UL0CXbqmlR5KGa/x5wgXr6Ic5wS740wIOhS5U?= =?us-ascii?Q?j8yvKaqDKHKTeqTfApHKoQsjPQDA1EINEcc3+h0dl4D1O5fbMt81MidnuES9?= =?us-ascii?Q?V2mCiAdqYZB0NYH8hi4eHCrmcqnQledn2NYWmUjJluDwcYQ3TY99UoVTkpNF?= =?us-ascii?Q?u+/cn9b10t4S1q2A1/gR3OZGpTWGxZUVTuRLKHy/PyORAu1mKCF/xwbl1neQ?= =?us-ascii?Q?2vQAkhoKReVI3Plz4D36bfiwR3MtG3gLyFP9n41ocKdnDM9bEA2j1MELzkYE?= =?us-ascii?Q?l0L90jsqmA=3D=3D?= X-OriginatorOrg: atomlin.com X-MS-Exchange-CrossTenant-Network-Message-Id: e0912188-bf26-47a0-9c00-08deb6b9d1fa X-MS-Exchange-CrossTenant-AuthSource: CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 May 2026 21:50:34.6372 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: e6a32402-7d7b-4830-9a2b-76945bbbcb57 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: TkAHWK8Ez54+l2VFx/joBc9+R/SN1Un+NbaRWlfIk2u8Gx2FJHOX36J3SinV/QU2AHKdBt35oJb6qtGLAylf0g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LO4P123MB6626 Hi, I have decided to drive this series forward on behalf of Daniel Wagner, the original author. The series has been rebased on v7.1-rc4-100-g8bc67e4db64a. This series introduces a new CPU isolation feature, "isolcpus=io_queue", designed to protect isolated cores from the disruptive hardware interrupts generated by high-performance multi-queue devices. When enabled, it fundamentally alters how the generic IRQ subsystem and the block layer (blk-mq) map hardware queues: 1. Restricted IRQ Affinity: Managed hardware interrupts are strictly confined to online housekeeping CPUs. 2. Transparent I/O Submission: Applications running on isolated CPUs can still seamlessly submit I/O requests; however, the resulting hardware completion interrupts are safely routed to a designated housekeeping CPU. 3. Topology-Aware Queue Allocation: The generic CPU-to-hardware-queue mapping logic is extended to distribute hardware contexts evenly among the available housekeeping CPUs, preventing MSI-X vector exhaustion while maintaining optimal cache locality where possible. To prevent I/O stalls, the block layer is additionally hardened to reject hot-plug requests that attempt to offline a housekeeping CPU if it is the last remaining CPU actively serving an online isolated core. The complex "top-down" mask plumbing introduced in v12, which modified struct irq_affinity and expanded block layer APIs, has been abandoned. It is replaced by a centralised approach: direct isolation querying via housekeeping_cpumask(HK_TYPE_IO_QUEUE) within the genirq/affinity subsystem. This architectural simplification successfully decouples core changes from driver-specific implementations. Please let me know your thoughts. Changes since v13: - Removed ineffective data_race() annotations around mask and cpu_present_mask pointers. Wrapping the pointers failed to suppress KCSAN warnings for the underlying inline bitmap memory accesses. - Fixed a silent validation bypass in blk_mq_map_hw_queues() caused by overlapping IRQ affinity masks by removing the short-circuiting optimisation and evaluating the active_hctx bitmap in a secondary pass. - Restored topology-aware multi-queue fallback by correctly routing missing IRQ affinity masks to the map_software path instead of the naive map-all fallback. - Dropped hctx->queue->disk->disk_name from warning to avoid a UAF. - Fixed an isolation leak where excess allocated hardware queues were improperly padded with irq_default_affinity. Because these queues are marked as managed, they bypassed user-space IRQ balancing; they are now safely padded with the housekeeping mask. - Enforced the housekeeping vector cap prior to evaluating driver-provided calc_sets() callbacks, preventing modern multi-queue drivers from bypassing the cap and wasting memory on dead queues. - Introduced a safety net to the vector calculation to prevent fatal -ENOSPC device probe aborts on heavily isolated systems where the housekeeping CPU count is lower than the device's structural minimum. - Removed an inaccurate claim stating that the io_queue isolation flag takes precedence over managed_irq. Both flags are parsed, evaluated, and enforced entirely independently by their respective subsystems. - Linked to v13: https://lore.kernel.org/lkml/20260513005509.135966-1-atomlin@atomlin.com/ Changes since v12: - Resolved TOCTOU race conditions against CPU hotplug events in blk_mq_map_queues() and group_mask_cpus_evenly() by taking lockless snapshots of the online CPU mask prior to algorithmic evaluation. - Migrated the active_hctx tracking to a dynamically sized bitmap (bitmap_zalloc), resolving a critical out-of-bounds memory write that occurred when hardware queues exceeded the system CPU count. - Wrapped the disk pointer fetch in blk_mq_hctx_can_offline_hk_cpu() with READ_ONCE() to prevent a TOCTOU NULL pointer dereference against concurrent device teardowns. - Introduced bitmap_empty() checks to prevent the mapping logic from routing unassigned CPUs into unallocated memory when all mapped CPUs are offline, safely forcing a fallback mapping instead. - Implemented a native two-stage distribution logic in group_mask_cpus_evenly() that first prioritises physically present CPUs to prevent I/O starvation before distributing remaining vectors to non-present CPUs for hotplug safety. - Restricted the maximum number of allocated vectors in irq_calc_affinity_vectors() to the weight of the housekeeping mask, preventing drivers from wasting memory on dead hardware queues that physically cannot be routed. - Added padding logic using irq_default_affinity for sets where isolation constraints yield fewer masks than requested vectors, preserving the 1:1 hardware queue mapping sequence for subsequent sets. - Fixed a logic flaw that prematurely rejected valid offline requests by manually iterating over cpu_online_mask and reverse-mapping to accurately detect isolated CPUs, properly permitting the offlining of non-housekeeping CPUs. - Corrected an absolute versus relative queue index calculation bug in blk_mq_map_queues() that was overwriting loop iterations, by iterating directly over the generated masks. - Replaced scoped __free cleanups with traditional goto unwinding in the block layer to align with subsystem styling guidelines. - Refined the io_queue kernel command-line parameter documentation for better clarity and precision. - Linked to v12: https://lore.kernel.org/lkml/20260422185215.100929-1-atomlin@atomlin.com/ Changes since v11: - Removed duplicate paragraph from the commit message in patch 11 (Marco Crivellari) - Ensure ZERO_SIZE_PTR is not returned by group_mask_cpus_evenly() (Marco Crivellari) - Linked to v11: https://lore.kernel.org/lkml/20260416192942.1243421-1-atomlin@atomlin.com/ Changes since v10: - Completely rewrote the isolcpus=io_queue documentation in Documentation/admin-guide/kernel-parameters.txt to clarify its exclusive application to managed IRQs, queue allocation limits, vector exhaustion prevention, and hardware interrupt routing (Ming Lei) - Fixed a stack frame bloat issue by avoiding the on-stack declaration of struct cpumask (Waiman Long) - Linked to v10: https://lore.kernel.org/linux-nvme/20260401222312.772334-1-atomlin@atomlin.com/ Changes since v9: - Fixed a page fault regression encountered when initialising secondary queue maps (e.g., NVMe poll queues). Restored the qmap->queue_offset to the mq_map assignment to ensure CPUs are strictly mapped to absolute hardware indices (Keith Busch) - Corrected the active_hctx tracker to utilise relative queue indices, preventing out-of-bounds mask assignments - Fixed the blk_mq_validate() sanity check to properly evaluate absolute queue indices against the offset-adjusted loop index - Corrected typographical errors within block/blk-mq-cpumap.c (Keith Busch) - Clarified the commit message regarding the removal of the !SMP fallback code, explicitly noting that the core scheduler now mandates SMP unconditionally (Sebastian Andrzej Siewior) - Added missing "Signed-off-by:" tags to properly record the patch series chain of custody - Linked to v9: https://lore.kernel.org/lkml/20260330221047.630206-1-atomlin@atomlin.com/ Changes since v8: - Added "Reviewed-by:" tags - Introduced irq_spread_hk_filter() to safely restrict managed IRQ affinity to housekeeping CPUs (Thomas Gleixner) - Removed the unsafe global static variable blk_hk_online_mask from blk-mq-cpumap.c and blk-mq.c. blk_mq_online_queue_affinity() now returns a stable pointer, delegating safe intersection to the callers to prevent concurrent modification races (Thomas Gleixner, Hannes Reinecke) - Resolved BUG: kernel NULL pointer dereference in __blk_mq_all_tag_iter reported by the kernel test robot during cpuhotplug rcutorture stress testing - Linked to v8: https://lore.kernel.org/lkml/20250905-isolcpus-io-queues-v8-0-885984c5daca@kernel.org/ Changes since v7: - Added commit 524f5eea4bbe ("lib/group_cpus: remove !SMP code") - Merged the new mapping logic directly into the existing function to avoid special casing - Refined the group_mask_cpus_evenly() implementation with the following updates: - Corrected the function name typo (changed group_masks_cpus_evenly to group_mask_cpus_evenly) - Updated the documentation comment to accurately reflect the function's behavior - Renamed the cpu_mask argument to mask for consistency - Added a new patch for aacraid to include the missing number of queues calculation - Restricted updates to only affect SCSI drivers that support PCI_IRQ_AFFINITY and do not utilise nvme-fabrics - Removed the __free cleanup attribute usage for cpumask_var_t allocations due to compatibility issues - Updated the documentation to explicitly highlight the limitations surrounding CPU offlining - Collected accumulated Reviewed-by and Acked-by tags - Linked to v7: https://patch.msgid.link/20250702-isolcpus-io-queues-v7-0-557aa7eacce4@kernel.org Changes since v6: - Sent out the first part of the series independently: https://lore.kernel.org/all/20250617-isolcpus-queue-counters-v1-0-13923686b54b@kernel.org/ - Added comprehensive kernel command-line documentation - Added validation logic to ensure the resulting CPU-to-queue mapping is fully operational - Rewrote the isolcpus mapping code to properly account for active hardware contexts (hctx) - Introduced blk_mq_map_hk_irq_queues, which utilizes the mask retrieved from irq_get_affinity() - Refactored blk_mq_map_hk_queues to require the caller to explicitly test for HK_TYPE_MANAGED_IRQ - Linked to v6: https://patch.msgid.link/20250424-isolcpus-io-queues-v6-0-9a53a870ca1f@kernel.org Changes since v5: - Reintroduced the io_queue type for the isolcpus kernel parameter - Prevented the offlining of a housekeeping CPU if an isolated CPU is still present, upgrading this behavior from a simple warning to a hard restriction - Linked to v5: https://lore.kernel.org/r/20250110-isolcpus-io-queues-v5-0-0e4f118680b0@kernel.org Changes since v4: - Rebased the series onto the latest for-6.14/block branch. - Updated the documentation regarding the managed_irq parameters - Reworded the commit message for "blk-mq: issue warning when offlining hctx with online isolcpus" for better clarity - Split the input and output parameters in the patch "lib/group_cpus: let group_cpu_evenly return number of groups" - Dropped the patch "sched/isolation: document HK_TYPE housekeeping option" - Linked to v4: https://lore.kernel.org/r/20241217-isolcpus-io-queues-v4-0-5d355fbb1e14@kernel.org Changes since v3: - Added the patch "blk-mq: issue warning when offlining hctx with online isolcpus" - Fixed the check in group_cpus_evenly(); the condition now properly uses housekeeping_enabled() instead of cpumask_weight(), as the latter always returns a valid mask - Dropped the Fixes: tag from "lib/group_cpus.c: honor housekeeping config when grouping CPUs" - Fixed an overlong line warning in the patch "scsi: use block layer helpers to calculate num of queues" - Dropped the patch "sched/isolation: Add io_queue housekeeping option" in favor of simply documenting the housekeeping hk_type enum - Added the patch "lib/group_cpus: let group_cpu_evenly return number of groups" - Collected accumulated Reviewed-by and Acked-by tags - Split the patchset by moving foundational changes into a separate preparation series: https://lore.kernel.org/linux-nvme/20241202-refactor-blk-affinity-helpers-v6-0-27211e9c2cd5@kernel.org/ - Linked to v3: https://lore.kernel.org/r/20240806-isolcpus-io-queues-v3-0-da0eecfeaf8b@suse.de Changes since v2: - Integrated patches from Ming Lei (https://lore.kernel.org/all/20210709081005.421340-1-ming.lei@redhat.com/): "virtio: add APIs for retrieving vq affinity" and "blk-mq: introduce blk_mq_dev_map_queues" - Replaced all instances of blk_mq_pci_map_queues and blk_mq_virtio_map_queues with the new unified blk_mq_dev_map_queues - Updated and expanded the helper functions used for calculating the number of queues - Added the CPU-to-hctx mapping function specifically to support the isolcpus=io_queue parameter - Documented the hk_type enum and the newly introduced isolcpus=io_queue parameter - Added the patch "scsi: pm8001: do not overwrite PCI queue mapping" - Linked to v2: https://lore.kernel.org/r/20240627-isolcpus-io-queues-v2-0-26a32e3c4f75@suse.de Changes since v1: - Updated the feature documentation for clarity and completeness - Split the blk/nvme-pci patch into smaller, logical commits - Dropped the HK_TYPE_IO_QUEUE macro in favor of reusing HK_TYPE_MANAGED_IRQ - Linked to v1: https://lore.kernel.org/r/20240621-isolcpus-io-queues-v1-0-8b169bf41083@suse.de Aaron Tomlin (1): genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs Daniel Wagner (7): scsi: aacraid: use block layer helpers to calculate num of queues lib/group_cpus: remove dead !SMP code lib/group_cpus: Add group_mask_cpus_evenly() isolation: Introduce io_queue isolcpus type blk-mq: use hk cpus only when isolcpus=io_queue is enabled blk-mq: prevent offlining hk CPUs with associated online isolated CPUs docs: add io_queue flag to isolcpus .../admin-guide/kernel-parameters.txt | 26 +- block/blk-mq-cpumap.c | 233 ++++++++++++++++-- block/blk-mq.c | 49 ++++ drivers/scsi/aacraid/comminit.c | 3 +- include/linux/group_cpus.h | 3 + include/linux/sched/isolation.h | 1 + kernel/irq/affinity.c | 31 ++- kernel/sched/isolation.c | 7 + lib/group_cpus.c | 108 +++++++- 9 files changed, 422 insertions(+), 39 deletions(-) base-commit: 8bc67e4db64aa72732c474b44ea8622062c903f0 -- 2.51.0