use ramfs instead of tmpfs. ramfs is a ramdisk (no swap) tmpfs can be both
in your /etc/fstab:
none /path/to/location ramfs defaults,size=512M 0 0
size parameter to whatever you like but be careful not to exceed your actual amount of ram.
the use of a ramfs instead of tmpfs is not something i would recommend. you will find yourself experiencing stability issues if something happens and you write a ton of data to your ramdisk. you can NOT unallocate ram from a ramfs. once your ramdisk (all of your ram) is full your system will seize up. ram is volatile memory, meaning once it looses power all data is gone. so if your ramdisk fills up your ram and you crash you will never see what was on your ram disk again. unlike ramfs, tmpfs limits its size.