linux - iotop shows kswapd0 at 99.99% with 0% DISK READ and DISK WRITE

I have a heavy postgres query. It takes over ten minutes to run. I'd like to upgrade my hardware to get it run faster. I think more RAM will help, but my motherboard is full so I'll need a whole new motherboard. I don't want to invest unless I know I'll get better results. Here's what I see in iotop:

Total DISK READ:      46.81 M/s | Total DISK WRITE:       0.00 B/s
  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                                                                                                                                               

   27 be/4 root        0.00 B/s    0.00 B/s  0.00 % 99.99 % [kswapd0]
 2514 be/4 postgres   46.81 M/s    2.45 M/s  0.00 % 18.36 % postgres: postgres db1 127.0.0.1(55328) SELECT
    1 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % init
    2 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kthreadd]
    3 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [ksoftirqd/0]
    4 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/0:0]
    5 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/u:0]
    6 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/0]
    7 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [watchdog/0]
    8 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/1]

    9 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/1:0]
   10 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [ksoftirqd/1]

Notice how the kswapd0 is hitting the hard drive the most (99.99% IO). However, the DISK READ and DISK WRITE and SWAPIN of kswap0 are all zero. What is kswap0 doing? Is it really hitting my hard drive? Would adding more RAM to this system help at all?