Swapd is a dynamic swapping manager for linux. it provides the system with as much swap space (virtual memory) as is required at a particular time by dynamically creating swap files. this is more convenient than using fixed swap files and/or partitions because they (a) are unused most of the time and are just taking up disk space; and (b) provide a limited amount of virtual memory.

on systems that have constant need for virtual memory it would still be wise to use a swap partition in parallel with dynamic swapping, since swap partitions provide much faster access than swap files.