title: PassengerMaxInstancesPerApp doesn't seem to work
body: <p>I have my rails applications on DreamHost VPS.
  By default, it has the following setting.</p>
  
  <pre><code>&lt;IfModule mod_passenger.c&gt;
  RailsAutoDetect off
  RackAutoDetect off
  PassengerMaxPoolSize 4
  PassengerPoolIdleTime 1200
  RailsAppSpawnerIdleTime 3600
  PassengerMaxInstancesPerApp 2
  PassengerRoot /dh/passenger
  PassengerRuby /usr/bin/ruby1.8
  &lt;/IfModule&gt;
  </code></pre>
  
  <p>As you can see, PassengerMaxInstancesPerApp is 2, which means that when multiple requests arrive, 2 rails instances will respond.</p>
  
  <p>However, my test shows different result.</p>
  
  <p>I created the following 2 test pages.</p>
  
  <ol>
  <li><a href="http://mis.digitalpowr.com/sandbox/door/hello" rel="nofollow">http://mis.digitalpowr.com/sandbox/door/hello</a> #=> outputs text 'Hello'   </li>
  <li><a href="http://mis.digitalpowr.com/sandbox/door/long_process" rel="nofollow">http://mis.digitalpowr.com/sandbox/door/long_process</a> #=> sleeps 30 seconds and outputs 'Done'</li>
  </ol>
  
  <p>If I call [1], it responds right away. If I call [2] and [1] immediately, [1] waits until [2] ends. This is against my expectation. If 2 requests are made at the same time, 2 instances should run. Why does it wait until another response ends?</p>
  
  <p>Thanks.</p>
  
  <p>Sam</p>