alloc_free_mem_region(9)

🌸 alloc_free_mem_region(9) — the Kernel API Manual moment 💅

okay so bestie, welcome to the Kernel API Manual entry for alloc_free_mem_region(9) — yes it's a mouthful, yes it's iconic, let's get into it 🎀

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✨ NAME ✨

alloc_free_mem_region — find a free region relative to @base 🦋

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🌈 SYNOPSIS 🌈

struct resource * alloc_free_mem_region (struct resource *base ,
unsigned long size , unsigned long align , const char *name );

like… that's the whole signature, no crumbs left behind 💜

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🫶 ARGUMENTS 🫶

• base — the resource that will parent the new resource 👑 (it's giving main character energy, everything hangs off this one)
• size — size in bytes of memory to allocate from base 📏
• align — the alignment requirements for the allocation 🎯
• name — the resource name 🏷️ (yes you have to name it, it's not nameless)

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💖 DESCRIPTION 💖

so here's the vibe: buses like CXL that can dynamically instantiate new memory regions need a method to allocate physical address space for those regions. periodt. 💫

what this does is allocate and insert a new resource to cover a free range in the span of base — and like, specifically a range that is unclaimed by a descendant of base, no cap 🙅‍♀️ like it's not gonna slide into somebody else's spot, it's finding the free real estate 🔥

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👀 SEE ALSO 👀

the whole friend group, fr fr — Kernel file ./kernel/resource.c plus:

• request_resource_conflict(9)
• request_resource(9)
• release_resource(9)
• find_next_res(9)
• walk_iomem_res_desc(9)
• region_intersects(9)
• find_resource_space(9)
• reallocate_resource(9)
• allocate_resource(9)
• lookup_resource(9)
• insert_resource_conflict(9)
• insert_resource(9)
• insert_resource_expand_to_fit(9)
• remove_resource(9)
• adjust_resource(9)
• resource_alignment(9)
• __request_region(9)
• __release_region(9)
• release_mem_region_adjustable(9)
• merge_system_ram_resource(9)
• devm_request_resource(9)
• devm_release_resource(9)
• devm_request_free_mem_region(9)

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okay but genuinely 💀 read the SEE ALSO list before you go poking at resources, bestie — it's long for a reason 🙈

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and that's the page! 🍓 this lil slice of the Kernel API Manual lives out of ./kernel, dated October 2026, and it's filed under alloc_free_mem_region(9) — mwah, slay, bye bestie 💋🧚‍♀️⭐