RFR: 8316959: Improve InlineCacheBuffer pending queue management [v3]

[Dean Long]

On Mon, 9 Oct 2023 08:34:09 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Maybe file an RFE to do this work in parallel threads to reduce safepoint pause time?
>
>> I don't see why atomics are needed here. Any GC threads calling queue_for_release() should be finished, and now we are single-threaded at a safepoint.
> 
> I found the `xchg` more convenient than explicitly nulling out `_pending_release` in a separate statement. The implicit atomic op for `xchg` is just incidental (and won't have any impact on performance).
> 
> Will file an rfe about making this parallel.

OK, a comment explaining that the atomic swap is convenient but not necessary would be helpful.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16059#discussion_r1350902457