RFR: 8252324: Signal related code should be shared among POSIX platforms

[Gerard Ziemski]

On Wed, 23 Sep 2020 21:00:47 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>>> > _Mailing list message from [Doerr, Martin](mailto:martin.doerr at sap.com) on
>>> > [hotspot-runtime-dev](mailto:hotspot-runtime-dev at openjdk.java.net):_ Hi Gerard,
>>> > sorry for the long delay. It took time to get our nightly tests working again on AIX.
>>> > I have seen an issue, but it may be unrelated to your change. We'll retest it.
>>> 
>>> I will take another look at AIX changes to see if I missed something.
>> 
>> I took another look at the changes and I have concerns over the following methods:
>> 
>> PosixSignals::SR_handler
>> PosixSignals::do_suspend
>> PosixSignals::do_resume
>> 
>> They seem to differ substantially in parts from the other POSIX platforms. In my early webrevs I have accounted for
>> those changes using "#if defined(AIX)", but during pre-reviews you asked me to revert to the common POSIX code.
>> Can you please take a look again and tell me if you are OK with the following SA related changes:
>> 
>> - using POSIX semaphores
>> - using the common POSIX code
>> 
>> I will upload, what I think (based only on the code diffs between the platforms as I lack AIX platform understanding)
>> the AIX platform needs here.
>
> I believe the reason for not using POSIX semaphores was that it is not supported on as400 PASE which we don't support
> in OpenJDK. I'm not aware of any problems when using this common POSIX code on AIX 7.2. Is SA supported on AIX? That
> would be new to me. But I'm not an expert for these topics. I hope that Thomas can find some time to take a look.

Reverted the last commit. Thank you for taking a look and testing - please let me know how it goes.

I have already tested this change here at Oracle a while ago, but I will do so once again...

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PR: https://git.openjdk.java.net/jdk/pull/157