I should clarify.

The meta-info in my buddy allocator is only intrinsic if the size of ram, and offset are constant. Additionally, there is a bitmap of constant size in .data[1].

Of course, in userspace, there would need to be 1 void*, 1 size_t, and a bitmap per PoT chunk of memory to manage.

For a 4096-byte page, on a 32-bit system, that would be 4 + 4 + 256 = 304 bytes of overhead.

C

[1]

The size of the bitmap (in bits) is given directly by the geometric series:

F(n) = sum(k, n-1) r^k = (1-r^n)/(1-r)

r is 2.

If 2^U is the memory size, and 2^L is the smallest granularity of allocation, then n = U - L + 1, and the number of bits in the bitmap is F( n ).

E.g. 64 bytes of memory, min 8-byte allocation, then F( 4 ) = 15 bits (2 bytes) are needed for the bitmap.