RFR: JDK-8259372: remove AIX related USE_LIBRARY_BASED_TLS_ONLY and THREAD_LOCAL special handling

[David Holmes]

On 11/01/2021 7:59 pm, Thomas Stuefe wrote:
> On Thu, 7 Jan 2021 22:42:02 GMT, David Holmes <dholmes at openjdk.org> wrote:
> 
>>> AIX 5.3 had buggy __thread support (see JDK-8176442).
>>> That's why we introduced a macro USE_LIBRARY_BASED_TLS_ONLY and set it only to 1 on AIX (different to the other platforms supported by the OpenJDK).
>>> However AIX 5.3 support was removed some time ago (currently we have a minimum requirement of AIX 7.X ) so the whole USE_LIBRARY_BASED_TLS_ONLY related coding could be removed.
>>
>> Hi Matthias,
>> We didn't introduce USE_LIBRARY_BASED_TLS_ONLY just for AIX, it was also added to aid the mobile project:
>> http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-November/020765.html
>> Before removing it we would need to have a broader discussion.
>> Thanks,
>> David
> 
> Hi Matthias,
> 
> Removal looks good. I have a small preference for leaving it in; but OTOS we never really test this coding since all main platforms use __thread. Maybe removal is good then. I'll defer to David for the final decision.

Sorry for the delay, I've emailed mobile-dev to see what their usage 
state is.

Cheers,
David

> Cheers, Thomas
> 
> -------------
> 
> PR: https://git.openjdk.java.net/jdk/pull/1976
>