def setup_swapfile(fname, size=None, maxsize=None):
    """
    fname: full path string of filename to setup
    size: the size to create. set to "auto" for recommended
    maxsize: the maximum size
    """
    swap_dir = os.path.dirname(fname)
    if str(size).lower() == "auto":
        try:
            memsize = util.read_meminfo()['total']
        except IOError:
            LOG.debug("Not creating swap: failed to read meminfo")
            return

        util.ensure_dir(swap_dir)
        size = suggested_swapsize(fsys=swap_dir, maxsize=maxsize,
                                  memsize=memsize)

    mibsize = str(int(size / (2 ** 20)))
    if not size:
        LOG.debug("Not creating swap: suggested size was 0")
        return

    util.log_time(LOG.debug, msg="Setting up swap file", func=create_swapfile,
                  args=[fname, mibsize])

    return fname