cpu_device_down(9)

💅 cpu_device_down(9)

okay so bestie, welcome to the cpu_device_down page — that's section 9 of the Kernel API Manual, and yes we're getting into the cpu-hotplug lore 🌸

---

✨ NAME ✨

cpu_device_down — bring down a cpu device 🫶

like... we're taking a cpu offline. that's the whole vibe.

---

✨ SYNOPSIS ✨

int cpu_device_down (struct device *dev );

---

✨ ARGUMENTS ✨

• dev — pointer to the cpu device you wanna offline 💅 this is the one that's catching strays.

---

✨ DESCRIPTION ✨

okay so real talk: this function is meant to be used by the device core cpu subsystem only. like, it's their function, it's giving main character energy, and they're not sharing 🎀

Other subsystems should use remove_cpu instead. no cap — if you're not the device core cpu subsystem, that's your function, go use it, i'm literally begging 🙈

---

✨ RETURN ✨

0 on success 🎉 or a negative errno code 😭 (iykyk, the classic "it worked or it very much didn't" binary).

---

✨ SEE ALSO ✨

Kernel file ./kernel/cpu.c — go read it, it's iconic ⭐

• struct cpuhp_cpu_state(9)
• struct cpuhp_step(9)
• cpuhp_invoke_callback(9)
• cpuhp_ap_update_sync_state(9)
• cpuhp_ap_report_dead(9)
• cpuhp_ap_sync_alive(9)
• clear_tasks_mm_cpumask(9)
• notify_cpu_starting(9)
• cpu_device_up(9)
• bringup_hibernate_cpu(9)
• __cpuhp_setup_state_cpuslocked(9)
• __cpuhp_remove_state_cpuslocked(9)

---

and that's the page!! 🦋 mwah 💖

source: ./kernel — dated October 2026 🎀 signing off, love u bestie, go offline that cpu responsibly 👑