RFR: 8313574: GenShen: Completing a global mark should also complete an old mark [v2]

[William Kemper]

On Mon, 14 Aug 2023 22:30:54 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> William Kemper has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
>> 
>>  - Merge branch 'shenandoah-master' into global-completes-old-mark
>>  - Fix assertions and update comments
>>  - Prepare for mixed collections after global cycle
>>  - Merge branch upstream into global-completes-old-mark
>>  - Have global mark also complete young and old marks
>>    
>>    This will have the remembered set scan use the mark bitmap following a global mark and eliminates the need to coalesce and fill during a global collection.
>
> src/hotspot/share/gc/shenandoah/heuristics/shenandoahOldHeuristics.hpp line 149:
> 
>> 147:   unsigned int get_coalesce_and_fill_candidates(ShenandoahHeapRegion** buffer);
>> 148:   bool has_coalesce_and_fill_candidates() const { return _last_old_region > 0; }
>> 149:   size_t coalesce_and_fill_candidates() const { return _last_old_region; }
> 
> The return value from `coalesce_and_fill_candidates()` (which by the way could be confused for an imperative action verb) lready available in `last_old_region_index()` although might be a good idea to rename appropriately? Also fine to leave as is, but it sounds to me like one name might work for both uses.

I agree, one (good) name for both is best.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/304#discussion_r1294849669