RFR: JDK-8262068: Improve G1 Full GC by skipping compaction for regions with high survival ratio [v11]

[Hamlin Li]

On Fri, 26 Mar 2021 20:18:26 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

>> Hamlin Li has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains seven commits:
>> 
>>  - Merge branch 'master' into g1-full-gc-optimization-00
>>  - reuse the "pin" mechanism (G1FullCollector._region_attr_table) to skip region compaction;
>>    deal with last-ditch full gc;
>>  - Merge branch 'master' into g1-full-gc-optimization-00
>>  - fix bot crash.
>>  - fix crash in G1CalculatePointersClosure::prepare_for_skipping_compaction when klass of dead objects is unloaded;
>>    other misc improvements.
>>  - reuse vm option MarkSweepDeadRatio; reuse G1RegionMarkStatsCache class; fix regression in Mark phase by inlining live words collection into mark_object()
>>  - JDK-8262068: Improve G1 Full GC by skipping compaction for regions with high survival ratio
>
> I'm going to approve these changes even if they are not yet done. I will be parental leave the coming two weeks, so I either do it now or not at all. I've discussed the remaining work with Thomas and we agree on how we want this to look in the end so as long as you get Thomas approval I'm on board.

Thanks Stefan, have a great vacation!

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PR: https://git.openjdk.java.net/jdk/pull/2760