RFR: 8349688: G1: Wrong initial optional region index when selecting candidates from retained regions [v2]

[Ivan Walulya]

On Tue, 18 Feb 2025 10:47:05 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Ivan Walulya 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 two additional commits since the last revision:
>> 
>>  - Merge remote-tracking branch 'upstream/master' into JDK-8349688-OptionalRegions
>>  - set_index_in_opt_cset correctly
>
> src/hotspot/share/gc/g1/g1CollectionSet.cpp line 486:
> 
>> 484: void G1CollectionSet::select_candidates_from_retained(double time_remaining_ms) {
>> 485:   uint num_initial_regions = 0;
>> 486:   uint prev_num_optional_regions = _optional_groups.num_regions();
> 
> It would be great if the code in `G1CollectionSet::select_candidates_from_marking` would check that the number of optional regions is zero as well when initializing its `num_optional_regions`.

Added, running it through testing.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23568#discussion_r1960061849