RFR: 8329488: Move OopStorage code from safepoint cleanup and remove safepoint cleanup code [v3]

[David Holmes]

On Tue, 9 Apr 2024 17:32:07 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Here, if needs_cleanup_requested was true and then we set it to false, we still return true so a concurrent thread setting it to true is ok because we still return 'true'.  That is, we need to do some work.   If we return false here, while another thread is setting it to true, we'll get it on the next periodic timeout.
>> The only reason for the store-release is because we use load-acquire and it's consistent. The comment refers to the old behaviour which was more complicated.  I removed the comment to remove the confusion.
>
> Ok, I think I restated what Kim said.

> The only reason for the store-release is because we use load-acquire and it's consistent.

So why do we use load-acquire? That is typically to pair with a store-release. We only need release semantics if someone seeing this store must see previous stores as well.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18375#discussion_r1558740137