hi folks,

the memory usage-balancing code that I posted about a while back
is in -current now.  here's the log message:

  add UBC memory-usage balancing.  we track the number of pages in use for
  each of the basic types (anonymous data, executable image, cached files)
  and prevent the pagedaemon from reusing a given page if that would reduce
  the count of that type of page below a sysctl-setable minimum threshold.
  the thresholds are controlled via three new sysctl tunables:
  vm.anonmin, vm.vnodemin, and vm.vtextmin.  these tunables are the
  percentages of pageable memory reserved for each usage, and we do not allow
  the sum of the minimums to be more than 95% so that there's always some
  memory that can be reused.


this should fix a lot of the interactive performance problems that people
have been reporting.  hopefully the default settings for the new sysctl
tunables will be reasonable for everyone, but I'm sure the enterprising
among us will want to experiment.  if anyone finds that things are
much better with different settings, please post about it.

as usual, let me know (or use send-pr) if there are any problems.

-Chuck