How to enable swap space on xen VPS?

Guys,

I did the following steps :

==========
root@onweb:/# dd if=/dev/zero of=/swap bs=1024 count=1048576
1048576+0 records in
1048576+0 records out
1073741824 bytes (1.1 GB) copied, 8.60256 s, 125 MB/s
root@onweb:/# mkswap /swap
mkswap: /swap: warning: don't erase bootbits sectors
on whole disk. Use -f to force.
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=00d2e2b5-0453-48b7-809b-4e405fadd9e8
root@onweb:/# chmod 0600 /swap
root@onweb:/# vi /etc/fstab //give entry like : /swap swap swap defaults,noatime 0 0
root@onweb:/# swapon -a
root@onweb:/# free -m
total used free shared buffers cached
Mem: 531 524 6 0 5 398
-/+ buffers/cache: 120 410
Swap: 1023 0 1023
root@onweb:/#
==========

Try :)