PTR_MAX_IDX_PER_PG
#define PTR_PG(x) (((x) & ~PTR_MAX_IDX_PER_PG) / PTR_CNT_PER_PG)
#define PTR_IDX(x) ((x) & PTR_MAX_IDX_PER_PG)
#define PTR_PG(x) (((x) & ~PTR_MAX_IDX_PER_PG) / PTR_CNT_PER_PG)
#define PTR_IDX(x) ((x) & PTR_MAX_IDX_PER_PG)