Question regarding Tomcat memory

Hi,

To make our tomcat  heap size memory  to 8 GB we have set the below=20
settings echo $CATALINA_OPTS -Xms8192M -Xmx8192M -Xss1024K=20
-XX:PermSize=3D64m -XX:MaxPermSize=3D256m -Dfile.encoding=3DCp1252 Please=20
suggest is this ok ? as we are observing the maximum heap size memory for=20
tomcat gets a reduced bit to  around 7756736K and it keeps flucatating. Is=
=20
this the normal behaviour?.
The OS we are using is Linux 8.