RFR: 8283710: JVMTI: Use BitSet for object marking

[Kim Barrett]

On Mon, 4 Apr 2022 21:53:28 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> > One open question is which MEMFLAGS to use. mtTracing doesn't seem to be exactly right. Should I templatize BitSet and make JVMTI use mtServiceability and JRF use mtTracing as it did before?
> 
> Yes, I think templatizing for MEMFLAGS makes sense (concurrentHashTable.hpp is too).

I haven't had time to look at the code, but I don't know about this.  Slapping a template parameter on everything isn't necessarily a good idea.  We recently (JDK-8283368) undid exactly this sort of thing in the cardset code, instead making the MEMFLAGS value a runtime parameter provided at construction time.  This avoids a bunch of generated code duplication, additional template syntax, and allows more implementation be put in .cpp files because it isn't a template.

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PR: https://git.openjdk.java.net/jdk/pull/7964