RFC: Move some code from gc/g1 to gc/shared ?

Roman Kennke rkennke at redhat.com
Wed Mar 9 16:54:08 UTC 2016

Hi there,

I'd like to propose to move some code from gc/g1 to gc/shared. We, in
Shenandoah land, are using a couple of things from G1, and I think it
would make sense to put them into gc/shared. I'd be interested in this
because I keep getting merge conflicts in the related files whenever I
pull changes from jdk9 into the Shenandoah tree.

Those would be the things I'd like to move:

- CMBitMap and related
- SATBQueue/PtrQueue and related
- ParallelCleaning and related
- StringDedup and related

For the most part, they can be moved as they are. Some of them need
renaming to avoid G1*. Some tiny pieces need some refactoring to
separate G1 concerns from the rest. The end result is that all the
relevant classes of the above list are in gc/shared, with no reference
to G1 left. None of the changes affect performance.

We already made the refactorings in Shenandoah tree. If there's
interest on your side to move things to gc/shared before even starting
to think about Shenandoah, I'd put together a patch & webrev for you to

What do you think?


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