perf_mmap__init
perf_mmap__init(&map[i], prev, overwrite, NULL);
perf_mmap__init(map, NULL, false, NULL);
void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
perf_mmap__init(&map[i].core, prev, overwrite, perf_mmap__unmap_cb);