I have packaged up Igor's change-sets for the finalization fix:

  http://bugs.squeak.org/view.php?id=7525
  http://bugs.squeak.org/view.php?id=7473

into their respective MC packages and uploaded them to the Inbox.

Recall the original discussion:

  http://lists.squeakfoundation.org/pipermail/vm-dev/2010-March/003958.html

I have been running with Igor's enhanced VM and image-side
finalization patches for a few weeks now.  The results are striking.
Squeak applications using large Weak-collections deteriorate to a
point of unusability without this fix because Squeak spends 95% of its
time in the finalization process, leaving no time for application
processing. With this fix installed, CPU utilization is 0% when the
application is idle, providing excellent responsiveness.

This is a big, big, win for any application that uses Weak
collections, and a win for Squeak overall because it's own use of
weak-collections is enhanced.

While it seems to be backward compatible, e.g. I am able to run the
enhanced VM on older images (including 3.9), and I am able to run with
these image changes on an older VM, both are required to take
advantage of the enhanced finalization.

I would like to push this into the trunk, but will need help from the
VMMaker developers for that piece.  David?

For Magma, this wil be the most exciting and important fix since
#becomeForward:copyHash: introduced back in 2004.

 - Chris