Hi Leo:
I was reading over you incremental GC posts from about a month ago, and read the referenced paper--quite nice work you've done in implementing the ideas there.
I have one question: What about finalizers? I may have just missed it, but it would seem that calling finalizers would require another sweep over the items newly resident on the free list (the left-over items in the from-space), which would (unfortunately) take time proportional to the number of freed object.
BUT, a nifty thing would be to actually delay finalization until an object is about to be re-used off of the free list. That is, treat ecru items as only-maybe free, and as they are pulled off of the free list for re-use, check to see if a finalizer needed to be called and if so, call it and move on to the next item on the free list (as the first one may now be referenced, and should be marked grey). This would allow finalization to be treated incrementally, at the cost of it happening "later" than it would otherwise (which I think is fine). But maybe this is what you had in mind already. This doesn't give ordered finalization, but that may be okay.
JEff
