STRUCT VMW_BO_DIRTY(9)

💖 struct vmw_bo_dirty 💖

okay so bestie, welcome to the Kernel API Manual, section 9, and today's main character is struct vmw_bo_dirty. yes it's a struct. yes it's about dirty info. no we're not being weird about it, it's literally dirty pages, like memory pages that got written to. put the eyebrow down. 🦋

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✨ NAME ✨

struct vmw_bo_dirty — the Dirty information for buffer objects. that's it, that's the whole vibe. it's the receipts for which pages got touched. 🎀

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📜 SYNOPSIS 📜

struct vmw_bo_dirty {
    struct kref ref_count;
    unsigned long start;
    unsigned long end;
    enum vmw_bo_dirty_method method;
    unsigned int change_count;
    unsigned long bitmap_size;
    unsigned long bitmap[];
 };

look at her. flexible array member at the end, absolute queen behavior. 👑

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🫶 Members 🫶

okay so let's go through the whole cast, no skipping, i would never:

• ref_count — the Reference count for this structure. and bestie listen to me very carefully: Must be first member! like, not "should", not "ideally", MUST. it's giving load-bearing first member energy, do not move her, do not pass go. 💀
• start — the First currently dirty bit. where the mess begins, honestly relatable. 🌸
• end — the Last currently dirty bit + 1. yes, plus one. it's a half-open range, it's exclusive, it's chic, it's math. 🧚
• method — the The currently used dirty method. that's an enum vmw_bo_dirty_method, and it's literally which strategy we're doing rn. slay. 💅
• change_count — the Number of consecutive method change triggers. so we're counting how many times in a row we flipped methods. keeping tabs. 🎀
• bitmap_size — the The size of the bitmap in bits. Typically equal to the nuber of pages in the bo. (yes "nuber" — that's a typo in the original, it lives here now, it's canon, we love her anyway 🙈). anyway: bits, in the bitmap, usually = pages in the bo. 🔥
• bitmap — the A bitmap where each bit represents a page. A set bit means a dirty page. one bit per page, set = dirty. that's the entire mechanic, it's honestly iconic in its simplicity. ⭐

ngl the whole struct is just "who got touched, and by which method" and honestly? same.

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👀 SEE ALSO 👀

• Kernel file ./drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c — go read the source bestie, it's right there
• vmw_bo_dirty_scan_pagetable(9)
• vmw_bo_dirty_scan_mkwrite(9)
• vmw_bo_dirty_scan(9)
• vmw_bo_dirty_pre_unmap(9)
• vmw_bo_dirty_unmap(9)
• vmw_bo_dirty_add(9)
• vmw_bo_dirty_release(9)
• vmw_bo_dirty_transfer_to_res(9)
• vmw_bo_dirty_clear_res(9)

every single one of them, linked, unsummarized, the full friend group. iykyk. 🫶

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and that's the page!! 🌈 shoutout to ./drivers/gpu/drm/vmwgfx for hosting this whole situation, dated October 2026 — yes, the future, she's ahead of her time, we stan a forward-dated manual page. mwah 💜 🎀 ✨