removing swap

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

When shutting down, why does removing swap take a long time? (What is it
doing?)

swapctl: removing /dev/wd0b as swap device
  PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
28267 root      94  -20    11M 1120K biowai/0   0:10 11.75% 11.72% swapctl

Cheers,

Patrick