vma_mmu_pagesize(9)

📦 version 7.3.1, in nixpkgs unstable

💖 vma_mmu_pagesize 💖

okay so bestie, welcome to section 9 of the Kernel API Manual — we're talking vma_mmu_pagesize(9) today and honestly? she's lowkey iconic. this is the page about the default MMU page size granularity for a VMA, and yes we're gonna get into it 🎀

✨ NAME ✨

vma_mmu_pagesize — Default MMU page size granularity for this VMA.

like literally that's it, that's her whole job 💅

🌸 SYNOPSIS 🌸

unsigned long vma_mmu_pagesize (struct vm_area_struct *vma );

so she takes one (1) pointer and hands you back an unsigned long. no drama. no cap 🫶

🦋 ARGUMENTS 🦋

  • vma — The user mapping. that's the struct vm_area_struct * bestie, the whole reason we're here ✨

💜 DESCRIPTION 💜

okay so here's the vibe check 👑

In the common case (the normal one, the default one, the one that just works 😌), the default page size used by the MMU matches the default page size used by the kernel — and if you wanna peep that one, go look at vma_kernel_pagesize. cute little sibling energy fr fr 🍓

But on architectures where it differs?? that's where it gets spicy 🔥 — an architecture-specific 'strong' version of this symbol is required. like, required required. not optional. the arch has to bring its own, periodt 💀

And here's the important part, the part where nobody's allowed to be confused 🙈: the default MMU page size is not affected by:

  • Transparent Huge Pages being in effect — nope, doesn't touch it, THP can be doing its whole thing and this value stays unbothered 💁‍♀️
  • any usage of larger MMU page sizes — also no, and that includes either architectural huge-page mappings or other explicit/implicit coalescing of virtual ranges performed by the MMU 🧚
bestie please internalise this one: THP and big pages are living their lives and they do NOT change what this function returns. it's giving "unaffected queen" 🌈

⭐ RETURN ⭐

The default MMU page size granularity for this VMA. that's the whole return value, that's what you get, slay 💖

🎀 SEE ALSO 🎀

Kernel file ./mm/vma.c — and the whole friend group 💕

go read them, they're all main character energy in their own way 😭👑

ngl the moral of the story: this is the default MMU page size granularity for a VMA, it matches the kernel's default in the common case, archs that differ must supply a 'strong' version, and bigger pages do not change it. iykyk 🧚✨

and that's the page!! 🎉 sign-off time: this lil beauty came out of the ./mm source tree, dated October 2026, and it lives in the Kernel API Manual. mwah, go touch some page tables 💅🫶🌸

📦 where this page comes from