Hi ..
The vswp file is used if the physical host is out of memory, and is basically what makes overcommitment of memory possible.
The .vswp file belongs to a VM. By default these are placed in each home dir. of any VM. This is per default the same size as the memory assigned for the VM unless you do reservations. If you do a 512MB memory reservation on a VM which has 2048MB assigned, the vswp file will then only be 1536MB..
Hope it helps....
/Rubeck