RFR: 8305898: Alternative self-forwarding mechanism

[Stefan Karlsson]

On Thu, 22 Aug 2024 09:44:12 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>>> What happens to successfully-promoted objects? ...
>> 
>> Successfully-forwarded objs are don't live in eden/from spaces, which are the spaces this closure is applied on. One can't have assert here, because as we iterate over eden/from spaces, we will encounter successfully-forwarded objs, but they should just be skipped.
>> 
>>> The else if part is needed when we later turn on UseCompactObjectHeaders...
>> 
>> I believe so, but it should be in the UseCompactObjectHeaders PR, not this one.
>
> Ok, thanks for the explanation!
> 
> I don't think it's needed for the UCOH part - the iterator fetched Klass*/size from forwardee if it encounters forwarded objects.

You didn't change the iterators for the Serial GC, only for Parallel. But, yes, we can deal with this in the UCOH PR.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20603#discussion_r1726744403