title: Memory usages high - Slow application response : Used memory value not decreasing + Free memory value not increasing
body: <p>When application is in use for few minutes then it slowly increases the <strong>Used</strong> memory value and decreases <strong>Free</strong> memory value. Application get very slow after few minutes. Why isn't it releasing the memory.</p>
  
  <p>System configuration :</p>
  
  <ul>
  <li>CPU : Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz (No. of processors : 4 / No. of cpu cores : 8)</li>
  <li>RAM : 30 GB</li>
  <li>OS : CentOS-7</li>
  </ul>
  
  <p>Application configuration :</p>
  
  <ul>
  <li>java version "1.8.0_171" -- build 1.8.0_171-b11</li>
  <li>apache-tomcat-7.0.55 </li>
  </ul>
  
  <p>Tomcat setting</p>
  
  <p><a href="https://i.stack.imgur.com/nyXV0.png" rel="noreferrer"><img src="https://i.stack.imgur.com/nyXV0.png" alt="enter image description here"></a></p>
  
  <p>Free -h command</p>
  
  <p><a href="https://i.stack.imgur.com/Uqvgz.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Uqvgz.png" alt="enter image description here"></a></p>
  
  <p>Top command</p>
  
  <p><a href="https://i.stack.imgur.com/jnWWL.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jnWWL.png" alt="enter image description here"></a></p>
  
  <p>.
  .</p>
  
  <p><strong>Used</strong> memory value showing 12 GB occupied and <strong>Free</strong> memory value showing 600 MB free. I have performed multiple concurrent user searches and run <strong>jcmd</strong> command to generate heapdump.hprof to analyze the memory usage and observed that heapdump file size is not more than 600 MB.</p>
  
  <p>Used memory is 12 GB and heapdump is of 600 MB - I don't know why memory is not releasing or getting free.</p>
  
  <p>Could any one please advise any read-up on how to setup/configure to improve memory usage for a particular h/w config.</p>