what's a literary term?? please help me :( like which literary term is indulged in this line: "all i did was smile and smile and smile.."

A literary term refers to a literary device used in literature by an author to achieve some effect for the reader. In Kamala Das’s poem “My Mother at Sixty-six,” Das uses a literary device known as repetition to communicate a specific emotion in the poem about her mother.
 With a closer look at the poem, we see that the poet is realizing that her beloved mother has become frail with age. She sees her mother’s face “ashen like that / Of a corpse,” and this saddens and frightens her. The poet looks out the window in order to “put that thought away” and focuses on other younger, fresher things, such as “young trees” and “merry children.” When the poet leaves her mother, she has that “familiar ache, [her] childhood’s fear,” of losing her mother. Instead of acting on the fear, the poet tries, once again, to think of happier things. Although she fears her mother’s impending death, the poet tells her mother that she will see her soon, and all the poet can do is “smile and smile and smile.” Das uses repetition in this line to communicate to the reader her insistence on not dwelling on her mother’s impending death. The reader gets the sense that she is trying to convince herself to think of other, happier things.