RFR: 8307058: Implementation of Generational ZGC [v6]

[Stefan Karlsson]

On Fri, 5 May 2023 06:28:59 GMT, Yadong Wang <yadongwang at openjdk.org> wrote:

>> Thanks for reporting. It would be interesting to see what address you get and compare it to the range [ZAddressHeapBase, ZAddressHeapBase+ZAddressOffsetMax).
>
> We emailed to erik to discuss this issue two months ago, and maybe he missed it.
> ZForwardingTest does not guarantee a successful invoke of os::commit_memory for ZAddressHeapBase, and we saw some conflicts between ZAddressHeapBase and the metadata address space on the RISC-V hardware of 39-bits virtual address. There is no failure in the normal initialization phase of JVM, because the commit order of them is guaranteed.

Could you provide the values for `reserved`, `ZAddressHeapBase`, and `ZAddressOffsetMax, when this test is failing. I'd like to know if we can make a workaround for you, or if we have to turn off the test for riscv.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13771#discussion_r1185751935