RFR: 8306541: Refactor collection set candidate handling to prepare for JDK-8140326 [v11]

[Thomas Schatzl]

On Thu, 11 May 2023 14:33:44 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Removed assert that is useless for now
>
> src/hotspot/share/gc/g1/g1CollectionSet.hpp line 152:
> 
>> 150:   uint _survivor_region_length;
>> 151: 
>> 152:   G1CollectionSetRegionList _initial_old_regions;
> 
> Why is the whole list saved in the field? I'd expect initial-old-regions is a transient list used to move regions from candidate list to cset (live only inside `G1CollectionSet::finalize_old_part`).
> 
> `_initial_old_regions` and `_optional_old_regions` share some similarity on  the name, but semantically, it's closer to eden/survior regions, so sth like `uint _initial_old_region_length;`.

I do not have a too strong opinion either way, so I'll change it (back).

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PR Review Comment: https://git.openjdk.org/jdk/pull/13666#discussion_r1192025147