re: unconfiguring swap at shutdown

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

   |    The following patch removes swap devices at shutdown. This is useful for
   |    example when typing reboot and having a raidframe partition... Comments?
   | 
   | 
   | please don't do this by default.
   | 
   | i don't mind moving the stuff to swapoff out of rc.d into the kernel
   | but please don't change the default.  it can be very slow in common
   | cases...
   
   Kernel option? Sysctl? Are you sure it is slow (and do you know
   why it is slow)? Because at that time there are no processes left,
   and from my experience unmounting filesystems with a lot of unwritten
   data is a lot slower, or it appears to be.

i think sysctl.

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.)


.mrg.