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([2601:600:947f:f020:85dc:d2b2:c5ee:e3c4]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-88d9680c323sm170712766d6.13.2025.12.26.13.37.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 26 Dec 2025 13:37:35 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: Date: Fri, 26 Dec 2025 16:37:31 -0500 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 24/33] kthread: Refine naming of affinity related fields To: Frederic Weisbecker , LKML Cc: =?UTF-8?Q?Michal_Koutn=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 , 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 References: <20251224134520.33231-1-frederic@kernel.org> <20251224134520.33231-25-frederic@kernel.org> In-Reply-To: <20251224134520.33231-25-frederic@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: GWa8-jVrU7w8FZoHmT41092YWJm0mt06IBW6gwZpJQ4_1766785057 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 491871A000A X-Stat-Signature: cm7wso3fhyamriqambmsetsgi9wq57at X-HE-Tag: 1766785059-512964 X-HE-Meta: U2FsdGVkX18TArfBRYqC+QPdZJa1HwKam8eJ7PgvU15KOebeGAMA5Vd7csyxv7JG0muACJdsqRcd36vPcK58kvqza/x4INe7IKvogue5v7HqQm82TOXYBBvpzTYQx5WP2yAZ61v6dwkSiqTuwwlMP/R8ZDGLM26FHAZqIhNuvSD1/L0OMuP7qgCSevbnYAi9edPNm7Mvoas2idKaony6i0RRHTKG0ga/QaLv9vAqcVnfln5rBtxFyi4C3xuFO7h8FlNaTkiV8GbnIXHYNW5JFp4dyVwrCEMosKXcU3VWoGdJMvnXdPY8cAQB97qP/FTmz8XUb0Oj2xsGnETI0oA85V5ULsfjfzhHV17w4DRsMqttrV5ZbXFve02o+zVA29sVsETrxl1gGArmWH5huENZeKB349BILYMJVTe32xY700QrJdC9iH029LhSANxIWRAkMuFiRB8+MeXDwQ6JW9KaqVgg7Ss+Wn8uL3+3MVgVval3OqMBF/XPQ6ZZO3H7wv9+BizO02q5XjNVeH0nqDND8u2g1U/7vuCILpos9D7Es/B9FNqIF6PvzaoaZHWGu4Y/Stj1G3DUHu8GhIeyvB+codssVimjhfcniqb+Et4Ql1Mlo93YEFPnp4Qq3+9nwuZ6BNgA3Q9J1I2NZ4uDC0CsYFI3BuaG3wxtoNYrFms+fhCS/JUCX0r4ExSYuCCcfqk8DjDl3/m1whEWcpG4eUk1pwW9oc9D5QZMSA4P3kyGOgnMIs2CaiuZ0qZiBQiSfeopA4CMhEnW/8vCOYy6Yt/rsEcd7/SQCoRNKOVuG/0pqRvDhpF5pA6UWFaCkPM3VDnrTWcH54plXUm9EH4THyMVQOwonjnXyOmx3xvVeaz0nz9EXSWNvWFXMQoZ60q9y6ydXpGGw4WP0DDNXN9S+mlLFpKnHHgxGSwxWOBYDme4gCUGgz/NdiqJlfjlAQPRBacVK5Bh7l4gg/qlnkVgASx 7Bb4U6hG kL+bjiwDOpdQ33r0dDeMHSD9jHSLSDQe8MK7B1Xj4dMUZ4bPaiTIb25y1NUYI3I2nC4R60pNrAoAGpVQcc0DM7jtCaGuseVioPKvQTinMu5i28C57sE4elzyW3aFNDP087ylgRKkEmrwSNBzv4jE+rRtFfDZmYSNqAwYhVnVmHEYs0HJESrXZmxDfPxref1TvsIzUhX+X7nV5Kd4NnW5RpO4oUh60ORECbHryLFGaQrdDJdwuhOi4Qgatr/69KCTqYYoHdMD+OjEzAqrlY/2N/Ywgv4pjxiP5cvh6KASauss+Dv36VIIRISFsc3kpQIuF1INDnYHmGal75vV5MBak8XsB2WIukvoMg07k2gRCKTde7sDnZEH8LSufZXq3E60o9bJdecw626oYK96pKbrNsk450l8ujfLNB3QmceTp04Zcc3VTj07PtivN6PI4OcAc0I4SEDba8aJtRXnjFqBJPhXrw8dBpyuRJQIHWeviZ0c4lTFl9Ww9UV+QznIAf4rXG9Wfm9mcn146WP2JvFzQjuQf2g== 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: On 12/24/25 8:45 AM, Frederic Weisbecker wrote: > 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 > --- > kernel/kthread.c | 38 +++++++++++++++++++------------------- > 1 file changed, 19 insertions(+), 19 deletions(-) > > diff --git a/kernel/kthread.c b/kernel/kthread.c > index 99a3808d086f..f1e4f1f35cae 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); > } > @@ -873,16 +873,16 @@ 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); > > scoped_guard (raw_spinlock_irqsave, &p->pi_lock) > set_cpus_allowed_force(p, affinity); > > - mutex_unlock(&kthreads_hotplug_lock); > + mutex_unlock(&kthread_affinity_lock); > out: > free_cpumask_var(affinity); > > @@ -903,9 +903,9 @@ 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)) > @@ -913,7 +913,7 @@ 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; Acked-by: Waiman Long