Erik wrote: > I'd like to make some changes to Kaffe to make it simpler to do more > precise GC.
Just for reference, so everyone's on the same page, Kaffe already does precise walking of Java objects (see gcFuncs.c:walkObject()). It does not precisely walk stacks. I believe it walks many native objects (like jthreads, etc) conservatively. The big problem with walking the stack isn't the Java stack as much as the native stack. You could walk the Java parts precisely, and the native bits conservatively, but I don't know what you'd win anything by doing this. Getting Kaffe to the point where the native stacks are mapped for precise GC would be a very significant effort. As I understand GC trade-offs, the big win for precise GC is the ability to update pointers and thus implement a compacting collector. Is there something else you're hoping to get out of precise stack walking? Another approach to consider is to implement GC-safe points (e.g., on method calls and backwards branches in Java code). Then you only have to track and update the stack maps at each safe point, this also makes writing GC-safe native code simpler, I think. I'm not sure if GC-safe points would have much of an effect on the stack maps, but it might be something to consider. -Pat ----- ----- ---- --- --- -- - - - - - Pat Tullmann [EMAIL PROTECTED] If Gates got a dime each time Windows crashed... Oh, nevermind...
