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Mon, 21 Sep 2026 09:22:40 +0000 X-Mizu-Trace-ID: 311c3a7172cefc8c X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Thomas Gleixner , Peter Zijlstra Cc: Ye Liu , Michal Hocko , SJ Park , Lorenzo Stoakes , Oleg Nesterov , akpm@linux-foundation.org, paulmck@kernel.org, mingo@redhat.com, rostedt@goodmis.org, jpoimboe@kernel.org, mic@digikod.net, david@kernel.org, linmiaohe@huawei.com, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, gourry@gourry.net, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, rientjes@google.com, shakeel.butt@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, will@kernel.org, boqun@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, tony.luck@intel.com, reinette.chatre@intel.com, x86@kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, pavel@kernel.org, lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, longman@redhat.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, mark.rutland@arm.com, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com Subject: [PATCH v4 05/15] cpu/hotplug: convert process iterator to for_each_process_rculock Date: Mon, 21 Sep 2026 17:20:51 +0800 Message-Id: <20260921092101.89285-6-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260921092101.89285-1-ye.liu@linux.dev> References: <20260921092101.89285-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EAC674000A X-Stat-Signature: hispedw93ey9xmmu7oi6excutp5szmmi X-Rspam-User: X-HE-Tag: 1789982561-535278 X-HE-Meta: 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 QtqD6pde 81B++zzPnkBYSLovZiBYiez/9HS7ioi6Uq2hGLtHe3YR4YhCS9swZxSmpprSQ4156oSZbZvabfuiyw4jUpW3mGaV93wVC+bT2mfcqO4RBrIG/dXrM9lljiM9qzjXsvtj9AeSw4q1aFRariq63m8jAcNoLVYZ2yGUqPxgVI8YorAYRGWlyQUiHfJTQmEJHHIcCCfVTz7urMNYHVOgOwNLUHxwbCZ78hSEPNz/rpd2PgWW2rmuzkkPUO1TKduu0+Lg8p6/vtMS4CznGZSF4rE4yq41gZhb366jwL6a7VEQHJox02Z1zhCX40kFNnyvpVSnSfF3Fya/9oNeFgTxSIRhs1sUdQpClyZHRDv5XGNgv9lMhY38fp7qbNSvUXpnGwC34yOn04Ds+SJOo29xZe7bhuPrjTlp6qbuW3jNN4jVTa5dAbQDZ+vwqjP6ZH/OlEkDN2xgqcb2TaIt2bHw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ye Liu Replace the manual rcu_read_lock()/rcu_read_unlock() pair combined with for_each_process() loop in kernel/cpu.c with for_each_process_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu). No functional change. Signed-off-by: Ye Liu Acked-by: Michal Hocko Reviewed-by: SJ Park Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: Oleg Nesterov --- kernel/cpu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index b3c8553d7bd6..00638d2abc0f 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1254,8 +1254,7 @@ void clear_tasks_mm_cpumask(int cpu) * full-fledged tasklist_lock. */ WARN_ON(cpu_online(cpu)); - rcu_read_lock(); - for_each_process(p) { + for_each_process_rculock(p) { struct task_struct *t; /* @@ -1268,7 +1267,6 @@ void clear_tasks_mm_cpumask(int cpu) arch_clear_mm_cpumask_cpu(cpu, t->mm); task_unlock(t); } - rcu_read_unlock(); } /* Take this CPU down. */ -- 2.25.1