RFR: JDK-8322943: runtime/CompressedOops/CompressedClassPointers.java fails on AIX [v2]

[Joachim Kern]

On Wed, 6 Mar 2024 13:31:00 GMT, Joachim Kern <jkern at openjdk.org> wrote:

>> Even after recent fixes like
>> https://bugs.openjdk.org/browse/JDK-8305765
>> the test runtime/CompressedOops/CompressedClassPointers.java fails on AIX.
>> 
>> This error results from the fact, that on AIX the shmat() allocation granularity is 256MB instead of the standard Pagesize (4KB or 64KB).
>> 
>> Because my first proposal (PR 17708) of introducing a new method os::vm_shm_allocation_granularity() in the shared hotspot code was rejected I now encapsulate the difference in ifdef AIX brackets.
>
> Joachim Kern has updated the pull request incrementally with one additional commit since the last revision:
> 
>   being less verbose

With my new commit I tried to be less verbose.
And indeed `os::attempt_reserve_memory_between()` is not in jdk21, but introduced by you, Thomas some months ago.

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PR Comment: https://git.openjdk.org/jdk/pull/18105#issuecomment-1980912042