pt_entry_make_write_clean(9)

📦 version 7.3.1, in nixpkgs unstable

💅 pt_entry_make_write_clean(9) — the kernel API manual, bestie edition 🎀

okay so real talk, this is a page from the Kernel API Manual and it's about one tiny little function that clears the "write dirty" bit on a page-table entry. sit down, hydrate, let's get into it 🧚

✨ NAME ✨

pt_entry_make_write_clean — make the entry write clean 🫧

like, literally the whole job. the name ate and left no crumbs.

🌸 SYNOPSIS 🌸

void pt_entry_make_write_clean (struct pt_state *pts );

that's it. that's the whole signature. no return value (it's void, so it gives you nothing back, king behavior 👑).

🦋 ARGUMENTS 🦋

  • pts — the table entry you want to change 💖 yes bestie, this is the one you're modifying. the entry. the table one.

🔥 DESCRIPTION 🔥

so here's the vibe: you call this and it modifies the entry so that pt_entry_is_write_dirty == false. periodt. that's the assignment.

now the important lore 👀 — the hardware isn't notified of this change immediately. it eventually finds out via a TLB flush, and that TLB flush is the point where the HW has to become synchronized. like, that's the moment. main character energy for the flush fr fr.

⚠️ so any "write dirty" that happens before the TLB flush can be lost — that's not a bug, that's just how it is. but once the TLB flush completes, all writes must make their entries write dirty. no cap. 😭

and there's a whole subtle thing about the format: it should alter the entry in a way that's compatible with any concurrent update from the HW. like it's sharing the entry with hardware and they need to not step on each other ✨ also — the entire contiguous entry is changed. the whole thing. not just a little piece. the entire contiguous entry 🫶

🌈 SEE ALSO 🌈

all the sibling functions, obviously. the whole friend group 💜

and that's the page!! 🍓 this lil baddie lives over in ./drivers/iommu/generic_pt and the version/date on it is October 2026 — so yeah, she's from the future, we respect her 💅✨ go make some entries write clean, bestie, i believe in you 🫶🎀

📦 where this page comes from