STRUCT GPU_BUDDY(9)

🌸 struct gpu_buddy(9) 🌸

okay bestie, welcome to the struct gpu_buddy(9) page from the Kernel API Manual — yes that's the manual name, no I'm not gonna make you read it twice 💅 this is the GPU binary buddy allocator and it's lowkey iconic.

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✨ NAME ✨

struct gpu_buddy — the GPU binary buddy allocator, aka the thing that hands out memory in tidy little power-of-two chunks 🎀

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🦋 SYNOPSIS 🦋

struct gpu_buddy {
    unsigned int n_roots;
    unsigned int max_order;
    u64 chunk_size;
    u64 size;
    u64 avail;
    u64 clear_avail;
  #ifdef CONFIG_LOCKDEP;
    struct lockdep_map *lock_dep_map;
  #endif;
 };

like, that's the whole vibe right there, no notes ✨

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🎀 Members 🎀

• n_roots — how many root blocks live in the roots array. that's it, that's the number 🫶
• max_order — the maximum block order, which is the log2 of (largest block size / chunk_size). math girlie moment 🧮
• chunk_size — the smallest allocation granularity, in bytes. important: it must be at least SZ_4K. no cap, that's a hard requirement 💀
• size — the total size, in bytes, of the address space this allocator is managing 👑
• avail — the total free space currently available for allocation, in bytes. the "how much can I still spend" field 💸
• clear_avail — free space available in the clear tree (that's the zeroed memory), in bytes. key detail: this is a subset of avail, not extra on top 🙈
• lock_dep_map — annotates the gpu_buddy API with a lock provided by the driver. it's giving lockdep realness 🔒

heads up, lock_dep_map only exists when CONFIG_LOCKDEP is defined, per the #ifdef up in the synopsis ⭐

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💖 Description 💖

so the buddy allocator gives you efficient power-of-two memory allocation with fast alloc and free operations — literally the whole point. it's super commonly used for GPU memory management, where allocations can get split into power-of-two block sizes. that's the aesthetic 🦋

Locking is on you, bestie. the user handles it. a simple mutex wrapped around gpu_buddy_alloc_blocks and gpu_buddy_free_block/gpu_buddy_free_list should suffice — that's straight from the page, so don't come for me 😭

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🌈 SEE ALSO 🌈

kernel file ./include/linux/gpu_buddy.h — go read it, it ate 🔥

• GPU_BUDDY_RANGE_ALLOCATION(9)
• GPU_BUDDY_TOPDOWN_ALLOCATION(9)
• GPU_BUDDY_CONTIGUOUS_ALLOCATION(9)
• GPU_BUDDY_CLEAR_ALLOCATION(9)
• GPU_BUDDY_CLEARED(9)
• GPU_BUDDY_TRIM_DISABLE(9)
• struct gpu_buddy_block(9)
• gpu_buddy_driver_set_lock(9)
• gpu_buddy_driver_lock_held(9)

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and that's the page!! sign-off time: this one came out of ./include/linux and it's dated October 2026 ⭐ that's the source and the date, bestie, we're done here 💜 🎀 🫶