This small script can be used to identify what is using up swap on any Linux system. An alternative is to use top , press O p [Enter]. Below are a few lines which will give you a breakdown of swap usage. Some processes will have multiple rows if they have multiple memory regions swapped out.

#!/bin/bash
printf "%-25s %-25s %-25s\n" "PID" "Swap (kB)" "Process"
printf "==============================================================================================\n"
for x in $(grep Swap /proc/[1-9]*/smaps 2>/dev/null | grep -v '\W0 kB' | tr -s ' ' | cut -d' ' -f-2 | sort -t' ' -k2 -n | tr -d ' ' | tail -20); do
printf "%-25s %-25s %-25s\n" $(echo $x | cut -d/ -f3) $(echo $x | cut -d: -f3) $(ps -p $(echo $x | cut -d/ -f3) -o comm=)
done