cpumask_any_andnot_but(9)

📦 version 7.3.1, in nixpkgs unstable

💅 cpumask_any_andnot_but(9) — from the Kernel API Manual, bestie 🎀

okay so we're in the Kernel API Manual today and the star of the show is cpumask_any_andnot_but(9). she's a cpu picker. she's got opinions. let's go ✨

🌸 NAME 🌸

cpumask_any_andnot_but — pick an arbitrary cpu from *mask1 & ~*mask2, but not this one. 🚫 like she's literally excluding one specific cpu from the whole situation, no cap.

✨ SYNOPSIS ✨

unsigned int cpumask_any_andnot_but (const struct cpumask *mask1 , const
struct cpumask *mask2 , int cpu );

that's the whole signature, character for character, don't @ me 🫶

🦋 ARGUMENTS 🦋

  • mask1 — the first input cpumask 💖 one half of the equation.
  • mask2 — the second input cpumask 💜 the other half, the one getting andnot-ed out.
  • cpu — the cpu to ignore 🙈 miss girl gets left on read.

🔥 DESCRIPTION 🔥

so the vibe is: you give her two masks and a cpu to skip, and she hands you back a cpu. simple. iconic.

if cpu == -1, the function returns the first matching cpu. periodt. 💅

and she returns >= nr_cpu_ids if no cpus are set — so like, if there's literally nothing matching, you get a value that's out of range, which is your signal that the well was dry 😭 no cpus for you.

ngl, always check that return value against nr_cpu_ids before you go using it as an actual cpu id. that's the whole warning, bestie, don't skip it 💀

👑 SEE ALSO 👑

she did NOT come alone. this is her whole friend group, and they all live in the kernel file ./include/linux/cpumask.h:

like, that's the entire cpumask cinematic universe and she's in it 🍓

okay that's the page!! source is ./include/linux, dated October 2026, and she's filed under cpumask_any_andnot_but(9) in the Kernel API Manual — go pick some cpus responsibly bestie, mwah 🧚‍♀️💜

📦 where this page comes from