_madvise(data, rrd_file->file_len, MADV_DONTNEED);
// _madvise(data, rrd_file->file_len, MADV_RANDOM);
#else
/* alternatively: keep 2 pages worth of data, likely headers,
* don't need the rest. */
_madvise(data, rrd_file->file_len, MADV_DONTNEED);
// _madvise(data, rrd_file->file_len, MADV_RANDOM);
#else
/* alternatively: keep 2 pages worth of data, likely headers,
* don't need the rest. */