how to exit a child process - _exit() vs. exit

Consider this code snippet:

pid_t cpid = fork();

if (cpid == -1) {
    perror("fork");
    exit(EXIT_FAILURE);
}

if (cpid == 0) { // in child
    execvp(argv[1], argv + 1);
    perror("execvp");
    _exit(EXIT_FAILURE);
}

// in parent

How shall I exit the child process if execvp returns? Shall I use exit() or _exit()?