zpool_dump_ddt
zpool_dump_ddt(NULL, &ddt->ddt_histogram[type][class]);
zpool_dump_ddt(&dds_total, &ddh_total);
zpool_dump_ddt(&dds_total, &ddh_total);
zpool_dump_ddt(dds, ddh);
extern void zpool_dump_ddt(const ddt_stat_t *, const ddt_histogram_t *);