title: What's the node.js memory breakdown?
body: <p>We are deploying a Node.js application. This app seems to be consuming way more RSS memory than it should. So we started to dive into things and we found the following, thanks to  <code>process.memoryUsage();</code></p>
  
  <ul>
  <li><p>The RSS memory grows quickly to about 400MB and stays more or less stable in a 400MB-500MB, with small ups and small downs (Garbage collector running?)</p></li>
  <li><p>The heapUsed quickly grows to 50MB and then stays at that level (between 20MB and 100MB).</p></li>
  <li><p>The heaptotal is always about 30MB more MB than the heapUsed.</p></li>
  </ul>
  
  <p>As you see there is a huge difference between the heap and the RSS, which is where I think we should focus. There doesn't seem to be any very significant leak in our heap.</p>
  
  <p>Now, what's in RSS that is not in the heap? I believe C extensions, and Buffers, right? If so, how can we debug that. What else should we look for?</p>