alloc_bootmem_cpumask_var(9)

🌸 alloc_bootmem_cpumask_var — a Kernel API Manual moment 💅

okay so bestie, we're in the alloc_bootmem_cpumask_var(9) era and honestly? it's giving "tiny function, huge consequences." buckle up 🎀

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✨ NAME ✨

alloc_bootmem_cpumask_var — grab yourself a struct cpumask straight out of the bootmem arena 🧺✨

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🦋 SYNOPSIS 🦋

void alloc_bootmem_cpumask_var (cpumask_var_t *mask );

that's it. that's the whole signature. no cap 🫶

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💖 ARGUMENTS 💖

• mask — a pointer to a cpumask_var_t, and that's literally where your cpumask comes back to you. hand it the address, it hands you the goods 🎁

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👑 DESCRIPTION 👑

so here's the tea, and it's kind of a big deal 😭 — this whole function is only defined when CONFIG_CPUMASK_OFFSTACK=y. if that config ain't set, it's a nop (it lives in <linux/cpumask.h>, iykyk).

when it does do its thing, it does one of exactly two things, and the range is honestly wild:

• it either returns an allocated (zero-filled) cpumask 💖 — clean, fresh, zeros everywhere, main character energy
• or it causes the system to panic 💀 — yes, fr fr, no in-between, no "sorry bestie, try again"

so like... iconic behavior, but also maybe hold your breath a little 🙈

⚠️ real talk: "panics the system" is not a vibe, it's a hard failure. respect it.

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🔥 SEE ALSO 🔥

• the kernel file ./lib/cpumask.c — that's where the lore lives 📖
• alloc_cpumask_var_node(9)
• free_cpumask_var(9)
• free_bootmem_cpumask_var(9) — the cleanup bestie, don't ghost it 🫶
• cpumask_local_spread(9)
• cpumask_any_and_distribute(9)
• cpumask_any_distribute(9)

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and that's the whole page, slay 💅✨ this one's from ./lib, dated October 2026, and it ate, no crumbs. go allocate something zero-filled and stay hydrated 🍓🌈👑