STATIC_FMT_BUF_SIZE
iter->fmt_size = STATIC_FMT_BUF_SIZE;
static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
iter->fmt_size += STATIC_FMT_BUF_SIZE;