DEFINE_KFIFO(9)

📦 version 7.3.1, in nixpkgs unstable

💅 DEFINE_KFIFO (okay so THIS macro, bestie)

So like, this page lives in the Kernel API Manual section 9, and it's all about a macro named DEFINE_KFIFO — which is literally the macro to define and initialize a fifo. That's the whole vibe. Define it, init it, done. Iconic behavior honestly ✨

📜 SYNOPSIS — the whole thing in one line

DEFINE_KFIFO (fifo , type , size );

Yes bestie that's it, that's the entire call. Three args, no notes. 🎀

🌸 ARGUMENTS — what each lil thing means

  • fifo — the name of the declared fifo datatype. Like, you're naming your fifo here. That's the name it'll go by. 🫶
  • type — the type of the fifo elements. Each slot in this fifo holds this type. Simple as that.
  • size — the number of elements in the fifo, and ⚠️ this must be a power of 2. Not "should be," not "we'd prefer it" — must be. Power of 2 or it's not gonna slay. 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024… you get it, iykyk. 💀

📝 NOTE — the lowkey important part

This macro can be used for global and local fifo data type variables. Both. Global? Sure. Local? Also yes. It's flexible like that, no cap. ✨

🔗 SEE ALSO — the whole friend group, fr fr

First things first: this lives in the kernel file ./include/linux/kfifo.h — that's the main character file for this whole saga. 👑

And then there's the extended fam, in this exact order:

That's the whole crew bestie, every single one, go read them too if you're obsessed with fifos the way I am 🦋

💖 Quick reminder before you go: size must be a power of 2. That's the one rule. Don't be the person who passes 3. 🙈

okay that's the page!! ily, go define some fifos 🧚

This lil cutie came from ./include/linux, dated October 2026, and it's part of the Kernel API Manual — page DEFINE_KFIFO(9) if you're searching for it. byeee 🎀✨

📦 where this page comes from