pcpu_free_area(9)

📦 version 7.3.1, in nixpkgs unstable

💅 pcpu_free_area(9) — Kernel API Manual, bestie edition

Okay so this is a page from the Kernel API Manual (section 9, the kernel-internals one, iykyk) and it's about pcpu_free_area — the little function that hands memory back to the percpu allocator. Let's get into it 🫶

✨ NAME ✨

pcpu_free_area — literally just frees the corresponding offset 💀

🌸 SYNOPSIS 🌸

int pcpu_free_area (struct pcpu_chunk *chunk , int off );

🎀 ARGUMENTS 🎀

  • chunk — the chunk of interest, aka the chunk you're obsessed with rn 👑
  • off — addr offset into chunk, the exact spot inside it 🎯

🦋 DESCRIPTION 🦋

So what does it actually do? Bestie, it figures out how big the allocation you're freeing is — using the boundary bitmap, bestie, the boundary bitmap — and then it clears the allocation map. That's it, that's the whole vibe. 🧹✨

⭐ RETURN ⭐

Number of freed bytes. That's the number it hands back to you, no cap 💖

🌈 SEE ALSO 🌈

The kernel file ./mm/percpu.c, plus the whole percpu friend group — here's the full roster, nobody gets left out 🫶:

💡 little note: pcpu_free_area lives in the ./mm source tree, and this page is dated October 2026. That's the tea 🍓

Go free those offsets, bestie — you got this 💅🔥

📦 where this page comes from