kho_reserve_scratch(9)

📦 version 7.3.1, in nixpkgs unstable

💖 kho_reserve_scratch(9) 💖

okay so bestie, welcome to another episode of Kernel API Manual — the section 9 girlies know what's up ✨. Today's main character is kho_reserve_scratch, and honestly? She's lowkey doing a lot of behind-the-scenes work so your kexec handover doesn't fall apart. Let's get into it 🎀

🌸 NAME 🌸

kho_reserve_scratch — reserve a contiguous chunk of memory for kexec 🫶

✨ SYNOPSIS ✨

void kho_reserve_scratch (void );

💅 ARGUMENTS 💅

  • void — no arguments. not a single one. she takes nothing and she still slays 💀

🦋 DESCRIPTION 🦋

okay so picture this: with KHO we can preserve arbitrary pages in the system — like, the whole vibe is keep whatever pages you want 💖. But here's the thing, bestie: when we go searching through the physical address space for target memory, we really need to still have a large contiguous region of memory available. So to make sure that happens, let's make sure we always have a large CMA region active. periodt ✨

and like, don't worry about that CMA region being "wasted" — it's only ever used for movable pages, which are literally not a problem for us during KHO, because we can just move them somewhere else. iconic behaviour, no cap 👑

🔥 SEE ALSO 🔥

Kernel file:

./kernel/liveupdate/kexec_handover.c

and the whole friend group 💜:

and that's the whole page, bestie 🌈 this one came to you from <pink>./kernel/liveupdate</pink> and it's dated <purple>October 2026</purple> — go forth and reserve that scratch memory, iykyk 💅💖

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