From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: "Frederic Weisbecker" <frederic@kernel.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Gabriele Monaco" <gmonaco@redhat.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Jens Axboe" <axboe@kernel.dk>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Lai Jiangshan" <jiangshanlai@gmail.com>,
	"Marco Crivellari" <marco.crivellari@suse.com>,
	"Michal Hocko" <mhocko@suse.com>,
	"Muchun Song" <muchun.song@linux.dev>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Phil Auld" <pauld@redhat.com>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"Roman Gushchin" <roman.gushchin@linux.dev>,
	"Shakeel Butt" <shakeel.butt@linux.dev>,
	"Simon Horman" <horms@kernel.org>, "Tejun Heo" <tj@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Waiman Long" <longman@redhat.com>,
	"Will Deacon" <will@kernel.org>,
	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 21/33] kthread: Refine naming of affinity related fields
Date: Mon, 13 Oct 2025 22:31:34 +0200	[thread overview]
Message-ID: <20251013203146.10162-22-frederic@kernel.org> (raw)
In-Reply-To: <20251013203146.10162-1-frederic@kernel.org>
The kthreads preferred affinity related fields use "hotplug" as the base
of their naming because the affinity management was initially deemed to
deal with CPU hotplug.
The scope of this role is going to broaden now and also deal with
cpuset isolated partition updates.
Switch the naming accordingly.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/kthread.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 31b072e8d427..c4dd967e9e9c 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -35,8 +35,8 @@ static DEFINE_SPINLOCK(kthread_create_lock);
 static LIST_HEAD(kthread_create_list);
 struct task_struct *kthreadd_task;
 
-static LIST_HEAD(kthreads_hotplug);
-static DEFINE_MUTEX(kthreads_hotplug_lock);
+static LIST_HEAD(kthread_affinity_list);
+static DEFINE_MUTEX(kthread_affinity_lock);
 
 struct kthread_create_info
 {
@@ -69,7 +69,7 @@ struct kthread {
 	/* To store the full name if task comm is truncated. */
 	char *full_name;
 	struct task_struct *task;
-	struct list_head hotplug_node;
+	struct list_head affinity_node;
 	struct cpumask *preferred_affinity;
 };
 
@@ -128,7 +128,7 @@ bool set_kthread_struct(struct task_struct *p)
 
 	init_completion(&kthread->exited);
 	init_completion(&kthread->parked);
-	INIT_LIST_HEAD(&kthread->hotplug_node);
+	INIT_LIST_HEAD(&kthread->affinity_node);
 	p->vfork_done = &kthread->exited;
 
 	kthread->task = p;
@@ -323,10 +323,10 @@ void __noreturn kthread_exit(long result)
 {
 	struct kthread *kthread = to_kthread(current);
 	kthread->result = result;
-	if (!list_empty(&kthread->hotplug_node)) {
-		mutex_lock(&kthreads_hotplug_lock);
-		list_del(&kthread->hotplug_node);
-		mutex_unlock(&kthreads_hotplug_lock);
+	if (!list_empty(&kthread->affinity_node)) {
+		mutex_lock(&kthread_affinity_lock);
+		list_del(&kthread->affinity_node);
+		mutex_unlock(&kthread_affinity_lock);
 
 		if (kthread->preferred_affinity) {
 			kfree(kthread->preferred_affinity);
@@ -390,9 +390,9 @@ static void kthread_affine_node(void)
 			return;
 		}
 
-		mutex_lock(&kthreads_hotplug_lock);
-		WARN_ON_ONCE(!list_empty(&kthread->hotplug_node));
-		list_add_tail(&kthread->hotplug_node, &kthreads_hotplug);
+		mutex_lock(&kthread_affinity_lock);
+		WARN_ON_ONCE(!list_empty(&kthread->affinity_node));
+		list_add_tail(&kthread->affinity_node, &kthread_affinity_list);
 		/*
 		 * The node cpumask is racy when read from kthread() but:
 		 * - a racing CPU going down will either fail on the subsequent
@@ -402,7 +402,7 @@ static void kthread_affine_node(void)
 		 */
 		kthread_fetch_affinity(kthread, affinity);
 		set_cpus_allowed_ptr(current, affinity);
-		mutex_unlock(&kthreads_hotplug_lock);
+		mutex_unlock(&kthread_affinity_lock);
 
 		free_cpumask_var(affinity);
 	}
@@ -876,10 +876,10 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask)
 		goto out;
 	}
 
-	mutex_lock(&kthreads_hotplug_lock);
+	mutex_lock(&kthread_affinity_lock);
 	cpumask_copy(kthread->preferred_affinity, mask);
-	WARN_ON_ONCE(!list_empty(&kthread->hotplug_node));
-	list_add_tail(&kthread->hotplug_node, &kthreads_hotplug);
+	WARN_ON_ONCE(!list_empty(&kthread->affinity_node));
+	list_add_tail(&kthread->affinity_node, &kthread_affinity_list);
 	kthread_fetch_affinity(kthread, affinity);
 
 	/* It's safe because the task is inactive. */
@@ -887,7 +887,7 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask)
 	do_set_cpus_allowed(p, affinity);
 	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
 
-	mutex_unlock(&kthreads_hotplug_lock);
+	mutex_unlock(&kthread_affinity_lock);
 out:
 	free_cpumask_var(affinity);
 
@@ -908,9 +908,9 @@ static int kthreads_online_cpu(unsigned int cpu)
 	struct kthread *k;
 	int ret;
 
-	guard(mutex)(&kthreads_hotplug_lock);
+	guard(mutex)(&kthread_affinity_lock);
 
-	if (list_empty(&kthreads_hotplug))
+	if (list_empty(&kthread_affinity_list))
 		return 0;
 
 	if (!zalloc_cpumask_var(&affinity, GFP_KERNEL))
@@ -918,7 +918,7 @@ static int kthreads_online_cpu(unsigned int cpu)
 
 	ret = 0;
 
-	list_for_each_entry(k, &kthreads_hotplug, hotplug_node) {
+	list_for_each_entry(k, &kthread_affinity_list, affinity_node) {
 		if (WARN_ON_ONCE((k->task->flags & PF_NO_SETAFFINITY) ||
 				 kthread_is_per_cpu(k->task))) {
 			ret = -EINVAL;
-- 
2.51.0
next prev parent reply	other threads:[~2025-10-13 20:34 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-13 20:31 [PATCH 00/33 v3] cpuset/isolation: Honour kthreads preferred affinity Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 01/33] PCI: Prepare to protect against concurrent isolated cpuset change Frederic Weisbecker
2025-10-14 20:53   ` Bjorn Helgaas
2025-10-13 20:31 ` [PATCH 02/33] cpu: Revert "cpu/hotplug: Prevent self deadlock on CPU hot-unplug" Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 03/33] memcg: Prepare to protect against concurrent isolated cpuset change Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 04/33] mm: vmstat: " Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 05/33] sched/isolation: Save boot defined domain flags Frederic Weisbecker
2025-10-23 15:45   ` Valentin Schneider
2025-10-13 20:31 ` [PATCH 06/33] cpuset: Convert boot_hk_cpus to use HK_TYPE_DOMAIN_BOOT Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 07/33] driver core: cpu: Convert /sys/devices/system/cpu/isolated " Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 08/33] net: Keep ignoring isolated cpuset change Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 09/33] block: Protect against concurrent " Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 10/33] cpu: Provide lockdep check for CPU hotplug lock write-held Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 11/33] cpuset: Provide lockdep check for cpuset lock held Frederic Weisbecker
2025-10-14 13:29   ` Chen Ridong
2025-10-13 20:31 ` [PATCH 12/33] sched/isolation: Convert housekeeping cpumasks to rcu pointers Frederic Weisbecker
2025-10-21  1:46   ` Chen Ridong
2025-10-21  1:57     ` Chen Ridong
2025-10-21  4:03     ` Waiman Long
2025-10-21  3:49   ` Waiman Long
2025-10-13 20:31 ` [PATCH 13/33] cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset Frederic Weisbecker
2025-10-21  4:10   ` Waiman Long
2025-10-22  1:36     ` Chen Ridong
2025-10-21 13:39   ` Waiman Long
2025-10-13 20:31 ` [PATCH 14/33] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Frederic Weisbecker
2025-10-21 19:16   ` Waiman Long
2025-10-21 19:28     ` Waiman Long
2025-10-13 20:31 ` [PATCH 15/33] sched/isolation: Flush vmstat " Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 16/33] PCI: Flush PCI probe workqueue " Frederic Weisbecker
2025-10-14 20:50   ` Bjorn Helgaas
2025-10-13 20:31 ` [PATCH 17/33] cpuset: Propagate cpuset isolation update to workqueue through housekeeping Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 18/33] cpuset: Remove cpuset_cpu_is_isolated() Frederic Weisbecker
2025-10-29 18:05   ` Waiman Long
2025-10-13 20:31 ` [PATCH 19/33] sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated() Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 20/33] PCI: Remove superfluous HK_TYPE_WQ check Frederic Weisbecker
2025-10-13 20:31 ` Frederic Weisbecker [this message]
2025-10-13 20:31 ` [PATCH 22/33] kthread: Include unbound kthreads in the managed affinity list Frederic Weisbecker
2025-10-21 22:42   ` Waiman Long
2025-10-13 20:31 ` [PATCH 23/33] kthread: Include kthreadd to " Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 24/33] kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 25/33] sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 26/33] cgroup/cpuset: Fail if isolated and nohz_full don't leave any housekeeping Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 27/33] sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 28/33] kthread: Honour kthreads preferred affinity after cpuset changes Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 29/33] kthread: Comment on the purpose and placement of kthread_affine_node() call Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 30/33] kthread: Add API to update preferred affinity on kthread runtime Frederic Weisbecker
2025-10-14 12:35   ` Simon Horman
2025-10-13 20:31 ` [PATCH 31/33] kthread: Document kthread_affine_preferred() Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 32/33] genirq: Correctly handle preferred kthreads affinity Frederic Weisbecker
2025-10-13 20:31 ` [PATCH 33/33] doc: Add housekeeping documentation Frederic Weisbecker
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