bpf_cpumask_test_cpu(9)

📦 version 7.3.1, in nixpkgs unstable

✨ bpf_cpumask_test_cpu(9) ✨

okay so bestie, welcome to the Kernel API Manual 💖 — today's main character is bpf_cpumask_test_cpu(9), and she's literally just here to answer one (1) question: is this CPU in this mask or not. no cap.

🌸 NAME 🌸

bpf_cpumask_test_cpu — test whether a CPU is set in a cpumask 🎀

🦋 SYNOPSIS 🦋

__bpf_kfunc bool bpf_cpumask_test_cpu (u32 cpu , const struct cpumask
       *cpumask );

that's the whole vibe. two arguments, one bool, zero drama 💅

💜 ARGUMENTS 💜

  • cpu — the CPU you're querying for. like, the one you're asking about. the subject of the investigation 🔍
  • cpumask — the cpumask you're querying for containing a CPU. she's the guest list, and you're checking if cpu made the cut 🎟️

🔥 RETURN 🔥

  • true — cpu is set in the cpumask. she's on the list, she's invited, slay 👑
  • false — cpu was not set in the cpumask, or cpu is an invalid cpu 💀 (yes, invalid cpu also gets a false, no special treatment, no exceptions, periodt)

🌈 SEE ALSO 🌈

the whole friend group 🫶 — plus the kernel file itself, ./kernel/bpf/cpumask.c, and our queen struct bpf_cpumask(9):

that's it, that's the whole page 💖 go forth and test your CPUs, bestie — and remember, invalid cpu = false, so don't come for her when she's just being honest 🙈

mwah 💋 — signed off from ./kernel/bpf, dated October 2026, your girl bpf_cpumask_test_cpu(9) 🎀✨

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