RFR: 8296875: Generational ZGC: Refactor loom code

[Erik Österlund]

On Tue, 15 Nov 2022 09:39:27 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> PS: I see JVM crashes when running Skynet with extra VM option: -XX:+VerifyContinuations on linux-aarch64 platform.
>> 
>> $java  --enable-preview -XX:+VerifyContinuations Skynet
>> 
>> 
>> # A fatal error has been detected by the Java Runtime Environment:
>> 
>> # after -XX: or in .hotspotrc:  SuppressErrorAt=#
>> #  Internal Error/stackChunkOop.cpp (/home/realfyang/openjdk-jdk/src/hotspot/share/oops/stackChunkOop.cpp:433), pid=1904185:433, tid=1904206
>> 
>> [thread 1904216 also had an error]#  assert(_chunk->bitmap().at(index)) failed: Bit not set at index 208 corresponding to 0x0000000637c512d0
>> 
>> #
>> # JRE version: OpenJDK Runtime Environment (20.0) (fastdebug build 20-internal-adhoc.realfyang.openjdk-jdk)
>> # Java VM: OpenJDK 64-Bit Server VM (fastdebug 20-internal-adhoc.realfyang.openjdk-jdk, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-aarch64)
>
>> @RealFYang did you have a chance to see if my RISC-V changes worked out for you?
> 
> Hi, I have performed tier1-3 tests on my linux-riscv64 HiFive Unmatched boards. Results looks good.
> Thanks for handling riscv at the same time :-)
> 
> PS: Also passed Skynet test with all GCs plus extra VM options: -XX:+VerifyStack -XX:+VerifyContinuations

Thanks @RealFYang!

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PR: https://git.openjdk.org/jdk/pull/11111