re: unconfiguring swap at shutdown

[matthew green <mrg%eterna.com.au@localhost>]

   | it's slow when you have a lot of swap in use and swapoff means bringing
   | them all back into memory.  and those transfer happen at PAGE_SIZE at
   | a time, which is a lot slower than 64KB at a time (which is what pageout
   | can manage.)
   
   How can you have a lot of swap in use when there are no processes left?

who said that there are no processes left?  most espcially when
the system has hung and you've dropped to ddb and reboot :-)
even reboot might not really kill programs...

   Or it does not matter, and swapoff means that it has to fetch each page
   of swap configured? Why does it have to do this anyway?

swapoff == removing a swap device from use, which means, in the
current code, brining all those pages back into ram.

i think there are probably better ways to do this, but i'm not
sure which would be the best one..


.mrg.