title: How Linux kernel decide to which memory zone to use?
body: <p>When I check pagetypeinfo</p>
  
  <blockquote>
    <p>cat /proc/pagetypeinfo</p>
  </blockquote>
  
  <p>I see three types of memory zones; </p>
  
  <ul>
  <li>DMA </li>
  <li>DMA32 </li>
  <li>Normal</li>
  </ul>
  
  <p>How Linux choose a memory zone to allocate a new page?</p>