sparse_index_init 1388 include/linux/mmzone.h #define sparse_index_init(_sec, _nid)  do {} while (0)
sparse_index_init   83 mm/sparse.c    static int __meminit sparse_index_init(unsigned long section_nr, int nid)
sparse_index_init  107 mm/sparse.c    static inline int sparse_index_init(unsigned long section_nr, int nid)