RFR: Add generations to freeset [v5]

[Kelvin Nilsen]

On Thu, 13 Apr 2023 16:26:25 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove debug instrumentation
>
> src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp line 991:
> 
>> 989:       if ((_old_capacity < to_reserve_old) && (r->is_trash() || (r->affiliation() == ShenandoahAffiliation::FREE))) {
>> 990:         clear_mutator_free(idx);
>> 991:         set_old_collector_free(idx);
> 
> this would read:
> 
> 
>   remove_from_mutator(idx);
>   add_to_old(idx);
> 
> 
> or
> 
> 
>     move_from_mutator_to_old(idx)
> 
> 
> in the suggested set membership nomenclature.
> 
> Also, since we are always dealing with things in `ShenandoahFreeSet`, I'd dispense with the `free` adjective altogether and make the names more compact.

I'll make this change now.  I'd prefer to make more radical refactoring changes later.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/250#discussion_r1170657612