If you’re short on hard disk space and would like to share the same SWAP partition in Linux and Windows, you can try the following trick:
1. Format the partition as a DOS partition and create the Windows SWAP file on it, but do not boot Windows yet.
2. Boot in Linux and save the partition to a file. Assuming the partition is on /dev/hda5 we’ll do a
dd if=/dev/hda5 of=/etc/dosswap
3. Compress the dosswap file with
gzip -9 /etc/dosswap
4. Add the following in your /etc/rc file to prepare and install the Linux SWAP. XXXX represents the number of blocks of the SWAP partition:
mkswap /dev/hda5 XXXXX
swapon -av
5. Add the newly-created partition to /etc/fstab .