RFR: 8306833: Change CardTable::_covered to static array [v2]

[Kim Barrett]

On Tue, 25 Apr 2023 14:56:43 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/gc/shared/cardTable.hpp line 60:
>> 
>>> 58: 
>>> 59:   // The covered regions should be in address order.
>>> 60:   MemRegion _covered[max_covered_regions];
>> 
>> The whole concept of covered_regions doesn't seem to belong in this class.  G1CardTable derives from
>> CardTable, but doesn't appear to use this at all.
>
> `_covered` is not really used by G1, so are some other fields, e.g. `_guard_region`.

Yeah, it looks like there are a bunch of hierarchy / abstraction bugs in this area.  OK, I'll agree this is a
step-wise improvement, with hopefully more to come.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/13636#discussion_r1177289723