RFR: 8315503: G1: Code root scan causes long GC pauses due to imbalanced iteration [v4]

[Thomas Schatzl]

On Mon, 25 Sep 2023 17:26:56 GMT, Ivan Walulya <iwalulya 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 four commits:
>> 
>>  - Merge branch 'master' into 8315503-code-root-scan-imbalance
>>  - iwalulya review - more (gtest) cleanup
>>  - iwalulya review
>>  - initial version that seems to work
>>    
>>    Contains kludge to avoid modification of currently scanned code root set.
>>    Ought to be fixed differently.
>>    
>>    Contains debug code in table scanners of CodeRootSet/CardSet to find out problems with table growing
>>    
>>    Hashcode hack for code root set, using copy&paste ZHash
>>    
>>    Shrink table after clean
>>    
>>    Bulk removal of nmethods from code root  sets after class unloading. From Ivan.
>>    
>>    Cleanup, resize after bulk delete, hashcode verification
>
> Still LGTM!

Thanks @walulyai @albertnetymk for your reviews

-------------

PR Comment: https://git.openjdk.org/jdk/pull/15811#issuecomment-1742516392