wp profile extra field

add_action( 'edit_user_profile', 'show_extra_profile_fields', 10 );

function show_extra_profile_fields( $user ) { ?>
    <table class="form-table">
        <tr>
            <th><label for="roll"><?php _e('Roll No.', 'frontendprofile'); ?></label></th>
            <td>
                <input type="text" name="roll" id="roll" value="<?php echo esc_attr( get_the_author_meta( 'roll', $user->ID ) ); ?>" class="regular-text" /><br />
                <span class="description"><?php _e('Please enter Roll No.', 'frontendprofile'); ?></span>
            </td>
        </tr>
    </table>
<?php }

add_action( 'personal_options_update', 'save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'save_extra_profile_fields' );

function save_extra_profile_fields( $user_id ) {
    if ( !current_user_can( 'edit_user', $user_id ) )
        return false;
    update_usermeta( $user_id, 'roll', $_POST['roll'] );
}