gc/shared/oopStorage.hpp contains the class definition for OopStorage, along with a lot of inline function and inner class definitions. It would be better to move the inline definitions to a .inline.hpp file. All of those inline definitions are related to iteration, and many clients don't use iteration. It might even be worthwhile having the following structure:

(1) oopStorage.hpp - contains just class OopStorage.

(2) oopStorage.inline.hpp - contains all the inline definitions
presently in oopStorage.hpp, except for the ParState stuff.

(3) oopStorageParState.inline.hpp - contains the ParState stuff.

Inclusion of the ParState header by non-GC code should be suspect.