MMAP_ALLOC_HEADER_SIZE
#define MMAP_ALLOC_CHUNK_SIZE ((32 * 4096) - MMAP_ALLOC_HEADER_SIZE)
size += MMAP_ALLOC_HEADER_SIZE;
return (void*)((uintptr_t)base + MMAP_ALLOC_HEADER_SIZE);
base = (void*)((uintptr_t)ptr - MMAP_ALLOC_HEADER_SIZE);