From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 52EF1E75458 for ; Wed, 24 Dec 2025 13:47:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 978EF6B00AD; Wed, 24 Dec 2025 08:47:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 96BB26B00AF; Wed, 24 Dec 2025 08:47:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 867136B00B0; Wed, 24 Dec 2025 08:47:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 762FB6B00AD for ; Wed, 24 Dec 2025 08:47:35 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 3F19189881 for ; Wed, 24 Dec 2025 13:47:35 +0000 (UTC) X-FDA: 84254492070.03.F2C47FB Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf19.hostedemail.com (Postfix) with ESMTP id 751B31A000A for ; Wed, 24 Dec 2025 13:47:33 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rWBEXiFX; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of frederic@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=frederic@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1766584053; a=rsa-sha256; cv=none; b=ISXpGDyW+KkydmZXBz5wsWEaDkA1L9xFnKsbZoT2t075b9neJeTftipAzH0Xssfemzgkz8 FYcV3X+ZVpbuUwp56OC2pK8+0dSO0zB2vnD3qFHC91aaeBLpSjFMxtK6lvDN4DUyi+b3rb xlFif3HT/UfgsVxakqUAHqj7MEARM6w= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rWBEXiFX; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of frederic@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=frederic@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1766584053; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=P2Ps57mPJ8qAkwxRqJia303cfJSZSh55xKC8m6/f21o=; b=c5VNig6LAqffl7usOqIg6id1huwOzw8AKIv6GtWAe6TpLtq3cgIUzWGLEoSFqQBhpLuikJ LePSNknIjqIzKUCuj4fvyuMM5Mi0z8fb5a4t3nje9uVU54uC5CjFKBZuBV3nz63IVTBehf wyGltoaRXJ5FnvKIy1fxpfr3vt+myNs= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id A5DF540C2E; Wed, 24 Dec 2025 13:47:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 132F5C19421; Wed, 24 Dec 2025 13:47:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766584052; bh=bEcbX7KWei/F/tdd1dqLNOJQoJehpFK4YPlUxFH95Ec=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rWBEXiFXFwOZeezwfBkkOxMAGA/N78W09k3qvuwX4GdIGU32CYAGAwxja/awX8kkV J3lGm3qkjnrv1DU4n/D3+knMeI8Y5sCMVs98kJIYMO9pHkuOD4PJxshTq7F7pfChdh i6PLAj9PGKTA/Zbb+TvC70uO+moyUZEEsRNxfxmYtaBRk0qczG15CJ/HqGyXIucU3w ZHCxrfSt5EWat662ghZxFaCSH0yQ3CKEivUeErRRJgr5sCzrmz5BnpwgNdwOt/I8Zw zCM2WZWmJBoBBojR9P4JLjLFjxus1c6N0lyGSId+Y0oAPl7VMqgeQTYyVkQ8EjgU12 My41ZMotzUzjQ== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 14/33] cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset Date: Wed, 24 Dec 2025 14:45:01 +0100 Message-ID: <20251224134520.33231-15-frederic@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251224134520.33231-1-frederic@kernel.org> References: <20251224134520.33231-1-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 751B31A000A X-Rspamd-Server: rspam10 X-Stat-Signature: exjejbb5wycqa4z64ozxnkbua3ctmdhz X-HE-Tag: 1766584053-19806 X-HE-Meta: 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 4kz+SoXB 7W0Z0AOF1OUCOtcBVsFf8fsKNbYWIrkVv5HOfCHgBSpCdT8FNfvCasKE8EHWrbCJ/14xMVqBlsM0I6T9dkIf4TDtse0xaOtqSry3pGAWNHlZrbhFzbSekA4hg3EKYfXEIrRRQRIsvZ0kicxDO3PaA1DkoISACLb4BKy0tP84uJNHTHEo5zKS29JNS+3QHrERO2Z9bJ28DGXFS6uPnFBVIJsZS4naxNG11suEQpc2qKbk5dR+oz1SA9c5iUd9dt4SNPMELgaU83AqNWXpPli03ZOSOdWvUvLrI40qRFToZT8lxdZbtmg7sbdgJkT1fllH0GI3O X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Until now, HK_TYPE_DOMAIN used to only include boot defined isolated CPUs passed through isolcpus= boot option. Users interested in also knowing the runtime defined isolated CPUs through cpuset must use different APIs: cpuset_cpu_is_isolated(), cpu_is_isolated(), etc... There are many drawbacks to that approach: 1) Most interested subsystems want to know about all isolated CPUs, not just those defined on boot time. 2) cpuset_cpu_is_isolated() / cpu_is_isolated() are not synchronized with concurrent cpuset changes. 3) Further cpuset modifications are not propagated to subsystems Solve 1) and 2) and centralize all isolated CPUs within the HK_TYPE_DOMAIN housekeeping cpumask. Subsystems can rely on RCU to synchronize against concurrent changes. The propagation mentioned in 3) will be handled in further patches. Signed-off-by: Frederic Weisbecker --- include/linux/sched/isolation.h | 7 +++ kernel/cgroup/cpuset.c | 3 ++ kernel/sched/isolation.c | 76 ++++++++++++++++++++++++++++++--- kernel/sched/sched.h | 1 + 4 files changed, 81 insertions(+), 6 deletions(-) diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h index 109a2149e21a..6842a1ba4d13 100644 --- a/include/linux/sched/isolation.h +++ b/include/linux/sched/isolation.h @@ -9,6 +9,11 @@ enum hk_type { /* Revert of boot-time isolcpus= argument */ HK_TYPE_DOMAIN_BOOT, + /* + * Same as HK_TYPE_DOMAIN_BOOT but also includes the + * revert of cpuset isolated partitions. As such it + * is always a subset of HK_TYPE_DOMAIN_BOOT. + */ HK_TYPE_DOMAIN, /* Revert of boot-time isolcpus=managed_irq argument */ HK_TYPE_MANAGED_IRQ, @@ -35,6 +40,7 @@ extern const struct cpumask *housekeeping_cpumask(enum hk_type type); extern bool housekeeping_enabled(enum hk_type type); extern void housekeeping_affine(struct task_struct *t, enum hk_type type); extern bool housekeeping_test_cpu(int cpu, enum hk_type type); +extern int housekeeping_update(struct cpumask *isol_mask, enum hk_type type); extern void __init housekeeping_init(void); #else @@ -62,6 +68,7 @@ static inline bool housekeeping_test_cpu(int cpu, enum hk_type type) return true; } +static inline int housekeeping_update(struct cpumask *isol_mask, enum hk_type type) { return 0; } static inline void housekeeping_init(void) { } #endif /* CONFIG_CPU_ISOLATION */ diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 5e2e3514c22e..e13e32491ebf 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1490,6 +1490,9 @@ static void update_isolation_cpumasks(void) ret = tmigr_isolated_exclude_cpumask(isolated_cpus); WARN_ON_ONCE(ret < 0); + ret = housekeeping_update(isolated_cpus, HK_TYPE_DOMAIN); + WARN_ON_ONCE(ret < 0); + isolated_cpus_updating = false; } diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 83be49ec2b06..a124f1119f2e 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -29,18 +29,48 @@ static struct housekeeping housekeeping; bool housekeeping_enabled(enum hk_type type) { - return !!(housekeeping.flags & BIT(type)); + return !!(READ_ONCE(housekeeping.flags) & BIT(type)); } EXPORT_SYMBOL_GPL(housekeeping_enabled); +static bool housekeeping_dereference_check(enum hk_type type) +{ + if (IS_ENABLED(CONFIG_LOCKDEP) && type == HK_TYPE_DOMAIN) { + /* Cpuset isn't even writable yet? */ + if (system_state <= SYSTEM_SCHEDULING) + return true; + + /* CPU hotplug write locked, so cpuset partition can't be overwritten */ + if (IS_ENABLED(CONFIG_HOTPLUG_CPU) && lockdep_is_cpus_write_held()) + return true; + + /* Cpuset lock held, partitions not writable */ + if (IS_ENABLED(CONFIG_CPUSETS) && lockdep_is_cpuset_held()) + return true; + + return false; + } + + return true; +} + +static inline struct cpumask *housekeeping_cpumask_dereference(enum hk_type type) +{ + return rcu_dereference_all_check(housekeeping.cpumasks[type], + housekeeping_dereference_check(type)); +} + const struct cpumask *housekeeping_cpumask(enum hk_type type) { + const struct cpumask *mask = NULL; + if (static_branch_unlikely(&housekeeping_overridden)) { - if (housekeeping.flags & BIT(type)) { - return rcu_dereference_check(housekeeping.cpumasks[type], 1); - } + if (READ_ONCE(housekeeping.flags) & BIT(type)) + mask = housekeeping_cpumask_dereference(type); } - return cpu_possible_mask; + if (!mask) + mask = cpu_possible_mask; + return mask; } EXPORT_SYMBOL_GPL(housekeeping_cpumask); @@ -80,12 +110,46 @@ EXPORT_SYMBOL_GPL(housekeeping_affine); bool housekeeping_test_cpu(int cpu, enum hk_type type) { - if (static_branch_unlikely(&housekeeping_overridden) && housekeeping.flags & BIT(type)) + if (static_branch_unlikely(&housekeeping_overridden) && + READ_ONCE(housekeeping.flags) & BIT(type)) return cpumask_test_cpu(cpu, housekeeping_cpumask(type)); return true; } EXPORT_SYMBOL_GPL(housekeeping_test_cpu); +int housekeeping_update(struct cpumask *isol_mask, enum hk_type type) +{ + struct cpumask *trial, *old = NULL; + + if (type != HK_TYPE_DOMAIN) + return -ENOTSUPP; + + trial = kmalloc(cpumask_size(), GFP_KERNEL); + if (!trial) + return -ENOMEM; + + cpumask_andnot(trial, housekeeping_cpumask(HK_TYPE_DOMAIN_BOOT), isol_mask); + if (!cpumask_intersects(trial, cpu_online_mask)) { + kfree(trial); + return -EINVAL; + } + + if (!housekeeping.flags) + static_branch_enable(&housekeeping_overridden); + + if (housekeeping.flags & BIT(type)) + old = housekeeping_cpumask_dereference(type); + else + WRITE_ONCE(housekeeping.flags, housekeeping.flags | BIT(type)); + rcu_assign_pointer(housekeeping.cpumasks[type], trial); + + synchronize_rcu(); + + kfree(old); + + return 0; +} + void __init housekeeping_init(void) { enum hk_type type; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 475bdab3b8db..653e898a996a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include -- 2.51.1