RFR: 8367993: G1: Speed up ConcurrentMark initialization [v8]

[Leo Korinth]

On Wed, 28 Jan 2026 11:03:32 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

>> Leo Korinth has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 21 commits:
>> 
>>  - Revert "Stefan J 4"
>>    
>>    This reverts commit 203d11979524126add9ee5d04174bde07a5a3f5a.
>>  - Revert "remove commented out code"
>>    
>>    This reverts commit 9d9df671574be7a15a30ef0af452629330cb4fd1.
>>  - Merge branch 'master' into _8367993
>>  - Merge branch '_master_jdk' into _8367993
>>  - Merge branch '_8373253' into _8367993
>>  - rename of method
>>  - Proposal by Stefan J
>>  - wip
>>  - Revert "8373253: Re-work InjectGCWorkerCreationFailure for future changes"
>>    
>>    This reverts commit d45ea8817ab2303b2decd8cbb2cd1bf5280aa181.
>>  - Revert "Fixup after comment from Ivan."
>>    
>>    This reverts commit 2aa8aa4b68027b62a8d4be1b86720fadfa48dda5.
>>  - ... and 11 more: https://git.openjdk.org/jdk/compare/90b54692...c5a7e2bb
>
> src/hotspot/share/gc/g1/g1YoungCollector.cpp line 1128:
> 
>> 1126: 
>> 1127: void G1YoungCollector::collect() {
>> 1128:   _g1h->_cm->fully_initialize();
> 
> Why did you revert the call to this location? Instead of having it in G1CollectedHeap::do_collection_pause_at_safepoint()?

I have now reapplied the patch. It seems we are all okay with the current position of `_g1h->_cm->fully_initialize();`, and that it can be moved after [JDK-8371720](https://bugs.openjdk.org/browse/JDK-8371720) has been fixed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28723#discussion_r2742035071