alloc_pt(9)

🎀 alloc_pt — the Kernel API Manual tea 🎀

okay so bestie, buckle up, because we're diving into alloc_pt(9) from the Kernel API Manual and honestly? she's a whole vibe. this is the custom page table allocator, and she is so important, like main character energy for real. ✨

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🌸 SYNOPSIS 🌸

void * alloc_pt (void *cookie , size_t size , gfp_t gfp );

like, that's the whole signature. cute, right? one function, three args, zero drama. 💅

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🦋 ARGUMENTS 🦋

• cookie — the cookie that got passed in at page table allocation time. yes, it's literally called a cookie and no, you can't eat it 😭 it's just the thing you handed over earlier so she remembers who you are. 🍪
• size — the size of the page table. and listen, this size should be fixed — determined at creation time based on the granule size. so don't be out here changing it later, that's not the move, fr fr. 📏
• gfp — the GFP flags. that's it, that's the description. flags. slay. 🚩

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💖 DESCRIPTION 💖

so why do we even have a custom allocator, you ask? great question bestie, love that for you. 💜

the whole reason is: we want to use a cache for page table allocations, so we can amortize the cost of the over-reservation that's done to allow asynchronous VM operations. like, that's the entire pitch. it's giving efficiency, it's giving resourceful, it's giving "we did the math so you don't have to." 🔥

no cap, that's the description. short and iconic. periodt. 👑

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🧚 RETURN 🧚

• returns non-NULL on success 🎉
• returns NULL if the allocation failed for any reason 💀

that's the whole return contract. if you get a pointer back, yay. if you get NULL, something went sideways and you should probably go check on her. 🙈

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🌈 SEE ALSO 🌈

okay this section is LONG and honestly kind of a flex, so let's get into it. first up, the kernel file herself:

• Kernel file ./drivers/gpu/drm/panthor/panthor_mmu.c

and now the whole friend group, the entire cast, the full roster — not skipping a single one, iykyk:

• struct panthor_as_slot(9)
• struct panthor_mmu(9)
• struct panthor_vm_pool(9)
• struct panthor_vma(9)
• struct panthor_vm_op_ctx(9)
• struct panthor_vm(9)
• struct panthor_vm_bind_job(9)
• free_pt(9)
• panthor_vm_has_unhandled_faults(9)
• panthor_vm_is_unusable(9)
• panthor_vm_active(9)
• panthor_vm_idle(9)
• panthor_vm_as(9)
• panthor_vm_alloc_va(9)
• panthor_vm_free_va(9)
• panthor_vm_get_bo_for_va(9)
• panthor_vm_pool_create_vm(9)
• panthor_vm_pool_destroy_vm(9)
• panthor_vm_pool_get_vm(9)
• panthor_vm_pool_destroy(9)
• panthor_vm_pool_create(9)
• panthor_mmu_suspend(9)
• panthor_mmu_resume(9)
• panthor_mmu_pre_reset(9)
• panthor_mmu_post_reset(9)
• panthor_vm_put(9)
• panthor_vm_get(9)
• panthor_vm_get_heap_pool(9)
• panthor_vm_heaps_sizes(9)
• panthor_vm_resv(9)
• panthor_vm_bind_job_put(9)
• panthor_vm_create(9)
• panthor_vm_bind_job_create(9)
• panthor_vm_bind_job_prepare_resvs(9)
• panthor_vm_bind_job_update_resvs(9)
• panthor_vm_bind_exec_sync_op(9)
• panthor_vm_map_bo_range(9)
• panthor_vm_unmap_range(9)
• panthor_vm_prepare_mapped_bos_resvs(9)
• panthor_mmu_unplug(9)
• panthor_mmu_init(9)
• panthor_mmu_debugfs_init(9)
• panthor_mmu_pt_cache_init(9)
• panthor_mmu_pt_cache_fini(9)

like, that's the whole squad. no one left behind. 🫶

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ok real talk, this page lives under ./drivers/gpu/drm/panthor and it's dated October 2026 — so go read those see-also entries, stay curious, and remember: alloc_pt is out here doing the allocator work so your page tables can thrive. 💅✨ bye bestie, mwah! 🎀🦋⭐