title: What is remembered set in G1 algorithms used for?
body: <p>I just read some blogs about G1 algorithm.</p>
  
  <p>The usage of remembered-set is confused to me.</p>
  
  <p>Here is what I think:</p>
  
  <p>Since we can use DFS to walk through every reference from GC-Roots, why do we need remembered-set?</p>
  
  <p>Cause all the blogs to say the reason why we use remembered-set is we don't need to check every region to see if there is an object that is referenced by GC-Roots</p>