STRUCT DRM_PAGEMAP_ZDD(9)

📦 version 7.3.1, in nixpkgs unstable

💅 STRUCT DRM_PAGEMAP_ZDD — GPU SVM zone device data

Okay bestie, so this is the struct drm_pagemap_zdd(9) page from the Kernel API Manual — yes it's a kernel manual, we're built different here. Sit down, grab a strawberry drink 🍓, and let's get into it.

✨ SYNOPSIS ✨

struct drm_pagemap_zdd {
    struct kref refcount;
    struct drm_pagemap_devmem *devmem_allocation;
    struct drm_pagemap *dpagemap;
 };

That's the whole vibe of the struct right there. Three members, no notes, iconic. 👑

🫶 MEMBERS 🫶

  • refcount — the reference count for the zdd. Literally just keeping track of how many besties are still holding onto it 💖
  • devmem_allocation — the device memory allocation. That's the goods right there ✨
  • dpagemap — a refcounted pointer to the underlying struct drm_pagemap. Not a plain pointer, a refcounted one — do not forget, iykyk 🔥

🌸 DESCRIPTION 🌸

So this structure is doing a lot of main character work, let's talk about it. It serves as a generic wrapper installed in page->zone_device_data — like, that's where it lives, that's its home 🏠

What it gives you is infrastructure for two things:

  1. Looking up a device memory allocation upon a CPU page fault 🔍
  2. Asynchronously releasing device memory once the CPU has no page references left 🦋

And the asynchronous release part? Highkey important. Because CPU page references can get dropped in IRQ contexts, but releasing device memory likely requires sleeping locks 😭 so you literally cannot do it inline. Asynchronous release is the whole slay here. No cap.

💀 Fr fr, don't try to release device memory synchronously from an IRQ context. The asynchronous machinery exists for a reason.

🎀 SEE ALSO 🎀

Grab a snack, this list is long and every single one of these is required reading bestie:

Like I said. Long. But we read all of them. 💅

That's the whole page bestie, and it's sourced from ./drivers/gpu/drm, dated October 2026, and it's literally titled struct drm_pagemap_zdd(9) in case you forgot. Mwah 💋 go read your Overview(9) and hydrate 🧚‍♀️✨

📦 where this page comes from