percpu_ref_kill_and_confirm(9)

💖 percpu_ref_kill_and_confirm(9) 💖

omg hi bestie, welcome to the Kernel API Manual — today’s main character is percpu_ref_kill_and_confirm, and she is here to drop the initial ref and schedule confirmation 💅✨

✨ NAME ✨

percpu_ref_kill_and_confirm — drop the initial ref and schedule confirmation 🎀

🌸 SYNOPSIS 🌸

void percpu_ref_kill_and_confirm (struct percpu_ref *ref , percpu_ref_func_t *confirm_kill );

🎀 ARGUMENTS 🎀

• ref — the percpu_ref to kill. yes, we’re ending it 💀
• confirm_kill — optional confirmation callback. if it’s not NULL, the kill confirmation gets scheduled; if it is NULL, there’s no confirmation callback to schedule. lowkey simple 🫶

🔥 DESCRIPTION 🔥

okay so this is equivalent to percpu_ref_kill, but it also schedules kill confirmation if confirm_kill is not NULL. confirm_kill, which may not block, will be called after ref is seen as dead from all CPUs — at which point all further invocations of percpu_ref_tryget_live will fail. see percpu_ref_tryget_live for details 👑

this function normally doesn’t block and can be called from any context, but bestie… it may block if confirm_kill is specified and ref is in the process of switching to atomic mode by percpu_ref_switch_to_atomic. so like, usually no blocking, but that specific situation? blocking. noted 💅

🚨 important vibe check: there are no implied RCU grace periods between kill and release. no cap.

🌈 SEE ALSO 🌈

kernel file ./lib/percpu-refcount.c has the whole friend group:

• percpu_ref_init(9)
• percpu_ref_exit(9)
• percpu_ref_switch_to_atomic(9)
• percpu_ref_switch_to_atomic_sync(9)
• percpu_ref_switch_to_percpu(9)
• percpu_ref_is_zero(9)
• percpu_ref_reinit(9)
• percpu_ref_resurrect(9)

stay slay, bestie 💜 this one comes from the ./lib source, dated October 2026 — percpu_ref_kill_and_confirm(9), out 💋✨