mc_get
if (__predict_false(mc_get(&mc, len, how, type, flags) != 0))
error = mc_get(mc, total + lspace, how, MT_DATA, flags);
error = mc_get(&mc, NLA_DATA_LEN(attrs.data), M_WAITOK, MT_DATA, 0);
int mc_get(struct mchain *, u_int, int, short, int);