RFR: 8256265: G1: Improve parallelism in regions that failed evacuation [v2]

[Stefan Johansson]

On Mon, 12 Sep 2022 11:39:06 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 12 commits:
>> 
>>  - Merge branch 'master' of gh:tschatzl/jdk into 8256265-parallel-evac-failure
>>  - disable G1EvacuationFailureALot by default again
>>  - Remove unneeded clear metadata phase
>>  - Remove debug code
>>  - More refactoring
>>  - Initial cleanup
>>  - some refactoring, fix clearing of opt index in cset
>>  - fix test
>>  - some cleanup
>>  - Cleanup, phase names, fixes
>>  - ... and 2 more: https://git.openjdk.org/jdk/compare/37df5f56...2628451d
>
> src/hotspot/share/gc/g1/g1CollectedHeap.cpp line 2948:
> 
>> 2946: 
>> 2947: void G1CollectedHeap::clear_bitmap_for_region(HeapRegion* hr, bool update_tams) {
>> 2948:   concurrent_mark()->clear_bitmap_for_region(hr, update_tams);
> 
> Instead of adding one more arg, I wonder if it's clearer to move the operation on `tams` to higher-level caller(s).

I agree with Albert, I think moving `hr->note_end_of_clearing();` out of `G1ConcurrentMark::clear_bitmap_for_region()` and handle it where needed is a cleaner approach.

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PR: https://git.openjdk.org/jdk/pull/9980