Swap space has two forms: one is the swap partition and the other is the swap file. In short, it reads and writes all disk operations.
Linux memory manages the entire memory through virtual memory, which manages physical memory and also manages swap swap space.
The role of swap partitions, or swap spaces, can be simply described as: when the physical memory of the system is not enough, it is necessary to release some of the space in physical memory for use by the currently running program. The freed space may come from programs that have not been manipulated for a long time, and the freed space is temporarily saved in the swap space until those programs run, recovering the saved data from the swap into memory. In this way, the system always does swap swap when physical memory is not enough. In fact, swap adjustments are critical to the performance of Linux servers, especially Web servers. By adjusting swap, you can sometimes bypass system performance bottlenecks and save on system upgrade costs.
Linux Swap Space