title: Clarification of meaning new JVM memory parameters InitialRAMPercentage and MinRAMPercentage
body: <p>Reference: <a href="https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8186315" rel="noreferrer">https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8186315</a></p>
  
  <p>I'm really struggling to find out what MinRAMPercentage does, especially compared to InitialRAMPercentage.</p>
  
  <p>I assumed that InitialRAMPercentage sets the amount of heap at startup, that MinRAMPercentage and MaxRAMPercentage set the bottom and top limit of heap that the JVM is allowed to shrink/grow to.</p>
  
  <p>Apparently that is not the case. When I start a JVM (with UseContainerSupport, having these new memory setting parameters) like so:</p>
  
  <pre><code>java -XX:+UseContainerSupport -XX:InitialRAMPercentage=40.0 -XX:MinRAMPercentage=20.0 -XX:MaxRAMPercentage=80.0 -XX:+PrintFlagsFinal -version | grep Heap
  </code></pre>
  
  <p>InitialHeap and MaxHeap get set, there is no "Minimum Heap Size" value that I can find; Consequently, that MinRAMPercentage never seems to get used.</p>
  
  <p>Super confused, and apparently, I'm not the only one; the OpenJ9 dudes seem to also not fully parse the intent of these options, as I've gathered <a href="https://github.com/eclipse/openj9/issues/1428" rel="noreferrer">here</a> and <a href="https://github.com/eclipse/openj9/pull/1699" rel="noreferrer">here</a>. They seem to have opted to simply not implement MinRAMPercentage afaics.</p>
  
  <p>So: What is the real intended usage and effect of setting MinRAMPercentage?</p>