Set the JVM Max ,Min heap and Perm size of JVM in AEM

Add the below details in start.bat/start.sh file of AEM:

CQ_JVM_OPTS='-server –Xms8192m –Xmx8192m -XX:MaxPermSize=1024M 

where as 

• Xms is Min heap - size can be increased depending on the your instance RAM size
• Xmx is Max heap - size can be increased depending on the your instance RAM size
•  MaxPermSize size can be increased depending on the your instance RAM size

finally restart the instance.