From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D9BEA1DEFE9; Wed, 24 Dec 2025 13:45:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766583933; cv=none; b=koN5V9sjYLcRt4bFZYt/YxkhFiKmoNoXP9WMbzj2U+5Iy7Y1eS0dQNTxP0Xjnyd4xk6zSqYemVivQr1cMXcV2W819d0Q8YQYWZMJkUh5PB2mZ4whIlI71P94DRTkplCU4ctzHWx7rLh2QT0QHlMGOKlNSLQgwgUycu1Cwiw2/Iw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766583933; c=relaxed/simple; bh=tK3Yaoy6unJ5tHzgM+8i6RExHWgxXGyyr5alAshg1RU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=mCIGD17QhNf0aDgIwRX5Dqa6oG9egX6Y0+RZy8Rg6/H03UoowUgfbh/ll/6VxpAuJx6YxW7Qno15K2SrifrXSxeLlGX9v85B1R3gkkV7RyaDyDHyLZLpqdvsplm4wNU6mCCQN1qi5DQrURDDIqdwq5CoaMU9v7W3CRLPxE+ohe8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uVp068q6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uVp068q6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4CBCC4CEFB; Wed, 24 Dec 2025 13:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766583932; bh=tK3Yaoy6unJ5tHzgM+8i6RExHWgxXGyyr5alAshg1RU=; h=From:To:Cc:Subject:Date:From; b=uVp068q6+NoKI3AKxIIX51WZN2Jzi9fLoN+QB2SdXLQh+BvI82O1SnOAi1wUKysT8 2Gx+3lcLrUemOtTJfD8eE18TmmMX6fiZpABw/ahwtYlpSgDTztcpI3oTtMB4pAiqNN m9kPVJBaJKsTFZhIULeXcmgaJ3C6o961eLzaKyONSEN2pM707fPKDmk4q+psrAQ1w4 VZ5iQe3+kpmbe/0RT5cv6YrpbsRyyUv24PXxW7FHAa1lgeGs0QXk5XeA4+7uk5NxWG sViGJtbTDgVkVGUDDjT0nXcwqYbxz/XbwOshBOTOQxUIawvq7Ufnn7f1TTgRtyVqPN 5Z2zHqnJrj31w== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Gabriele Monaco , Chen Ridong , Michal Koutny , linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, Ingo Molnar , "David S . Miller" , Greg Kroah-Hartman , Michal Hocko , Roman Gushchin , Peter Zijlstra , Bjorn Helgaas , Catalin Marinas , Phil Auld , Andrew Morton , Paolo Abeni , "Rafael J . Wysocki" , Will Deacon , Thomas Gleixner , Lai Jiangshan , Waiman Long , Vlastimil Babka , Eric Dumazet , Jakub Kicinski , Muchun Song , netdev@vger.kernel.org, Danilo Krummrich , Johannes Weiner , linux-mm@kvack.org, Jens Axboe , Marco Crivellari , Tejun Heo , Shakeel Butt , Simon Horman , cgroups@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH 00/33 v5] cpuset/isolation: Honour kthreads preferred affinity Date: Wed, 24 Dec 2025 14:44:47 +0100 Message-ID: <20251224134520.33231-1-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi, The kthread code was enhanced lately to provide an infrastructure which manages the preferred affinity of unbound kthreads (node or custom cpumask) against housekeeping constraints and CPU hotplug events. One crucial missing piece is cpuset: when an isolated partition is created, deleted, or its CPUs updated, all the unbound kthreads in the top cpuset are affine to _all_ the non-isolated CPUs, possibly breaking their preferred affinity along the way Solve this with performing the kthreads affinity update from cpuset to the kthreads consolidated relevant code instead so that preferred affinities are honoured. The dispatch of the new cpumasks to workqueues and kthreads is performed by housekeeping, as per the nice Tejun's suggestion. As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set from isolcpus= and cpuset isolated partitions. Housekeeping cpumasks are now modifyable with specific synchronization. A big step toward making nohz_full= also mutable through cpuset in the future. Changes since v4: * Add more tags * Rebase on v6.19-rc2 with latest cpuset changes * Accomodate timers migration isolation * Rename housekeeping_update() parameter from mask to isol_mask (Chen Ridong) * Link housekeeping documentation to core-api git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git kthread/core-v5 HEAD: 3c0ee047f05f361f215521424f5e789dfffcafc1 Merry Christmas, Frederic --- Frederic Weisbecker (33): PCI: Prepare to protect against concurrent isolated cpuset change cpu: Revert "cpu/hotplug: Prevent self deadlock on CPU hot-unplug" memcg: Prepare to protect against concurrent isolated cpuset change mm: vmstat: Prepare to protect against concurrent isolated cpuset change sched/isolation: Save boot defined domain flags cpuset: Convert boot_hk_cpus to use HK_TYPE_DOMAIN_BOOT driver core: cpu: Convert /sys/devices/system/cpu/isolated to use HK_TYPE_DOMAIN_BOOT net: Keep ignoring isolated cpuset change block: Protect against concurrent isolated cpuset change timers/migration: Prevent from lockdep false positive warning cpu: Provide lockdep check for CPU hotplug lock write-held cpuset: Provide lockdep check for cpuset lock held sched/isolation: Convert housekeeping cpumasks to rcu pointers cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset sched/isolation: Flush memcg workqueues on cpuset isolated partition change sched/isolation: Flush vmstat workqueues on cpuset isolated partition change PCI: Flush PCI probe workqueue on cpuset isolated partition change cpuset: Propagate cpuset isolation update to workqueue through housekeeping cpuset: Propagate cpuset isolation update to timers through housekeeping timers/migration: Remove superfluous cpuset isolation test cpuset: Remove cpuset_cpu_is_isolated() sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated() PCI: Remove superfluous HK_TYPE_WQ check kthread: Refine naming of affinity related fields kthread: Include unbound kthreads in the managed affinity list kthread: Include kthreadd to the managed affinity list kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN kthread: Honour kthreads preferred affinity after cpuset changes kthread: Comment on the purpose and placement of kthread_affine_node() call kthread: Document kthread_affine_preferred() doc: Add housekeeping documentation Documentation/core-api/housekeeping.rst | 111 ++++++++++++++++++++++ Documentation/core-api/index.rst | 1 + arch/arm64/kernel/cpufeature.c | 18 +++- block/blk-mq.c | 6 +- drivers/base/cpu.c | 2 +- drivers/pci/pci-driver.c | 71 ++++++++++---- include/linux/cpu.h | 4 + include/linux/cpuhplock.h | 1 + include/linux/cpuset.h | 8 +- include/linux/kthread.h | 1 + include/linux/memcontrol.h | 4 + include/linux/mmu_context.h | 2 +- include/linux/pci.h | 3 + include/linux/percpu-rwsem.h | 1 + include/linux/sched/isolation.h | 16 +++- include/linux/vmstat.h | 2 + include/linux/workqueue.h | 2 +- init/Kconfig | 1 + kernel/cgroup/cpuset.c | 68 +++++++------- kernel/cpu.c | 42 ++++----- kernel/kthread.c | 160 +++++++++++++++++++++----------- kernel/sched/isolation.c | 144 +++++++++++++++++++++++----- kernel/sched/sched.h | 4 + kernel/time/timer_migration.c | 25 +++-- kernel/workqueue.c | 17 ++-- mm/memcontrol.c | 25 ++++- mm/vmstat.c | 15 ++- net/core/net-sysfs.c | 2 +- 28 files changed, 554 insertions(+), 202 deletions(-)