Comment # 3 on bug 1188277 from Ruediger Oertel

please request a worker with more memory via a _constraints file, example:

cat _constraints
<constraints>
  <hardware>
    <physicalmemory>
      <size unit="G">4</size>
    </physicalmemory>
  </hardware>
  <overwrite>
    <conditions>
      <arch>s390x</arch>
    <hardware>
      <memory>
        <size unit="G">8</size>
      </memory>
    </hardware>
  </overwrite>
</constraints>