Add Swap Partition in Linux/Ubuntu

  Create a 512MB swap file
  #dd if=/dev/zero of=/mnt/new.swap bs=1M count=512
  Change Permission to new.swap
  #chmod 600 /mnt/new.swap
  Formatting that file to create a swapping device:
  #mkswap /mnt/512Mb.swap
  Adding the swap to the running system:
  #swapon /mnt/512Mb.swap
  To check swap info
  #cat /proc/meminfo.
 Making the change permanent, open fstab 
 #  vi /etc/fstab
Add below line at the end of the file and save.
/mnt/new.swap none swap sw 0 0