STRUCT TTM_GLOBAL(9)

🌸 struct ttm_global(9) 🌸

okay so bestie, welcome to the Kernel API Manual — yes, that's the manual name, and yes, we're literally reading kernel docs together, this is our thing now 💅

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✨ NAME ✨

struct ttm_global — the buffer object driver's global data, like the group chat settings for the whole driver, no cap 🫶

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🦋 SYNOPSIS 🦋

struct ttm_global {
    struct page *dummy_read_page;
    struct list_head device_list;
    atomic_t bo_count;
};

three members, all iconic in their own way, let's get into it ⭐

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🎀 Members 🎀

• dummy_read_page — a struct page *, i.e. a pointer to a dummy page that gets used when somebody maps requests for pages that are unpopulated (empty, no vibes, nothing home). and here's the key part bestie: it's constant after init — set it once at init and then leave it alone, periodt 🙈
• device_list — a struct list_head holding the list of buffer object devices. it is protected by ttm_global_mutex 🔥 so like, respect the lock or it's giving chaos, fr fr
• bo_count — an atomic_t with the number of buffer objects allocated by devices. literally just a count, but make it atomic 💀

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🌈 SEE ALSO 🌈

• Kernel file ./include/drm/ttm/ttm_device.h
• struct ttm_device(9)

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💖 reminder bestie: dummy_read_page stays constant after init, and device_list lives and dies by ttm_global_mutex. no shortcuts 🫶

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and that's the whole page! this little gem lives in ./include/drm/ttm and the docs are dated October 2026, filed under struct ttm_global(9) — mwah, go read your kernel headers, ily, bye 👑✨🍓