RFR: 8356556: AArch64: No need for acquire fence in safepoint poll in FFM [v2]

[David Holmes]

On Tue, 17 Jun 2025 07:31:45 GMT, Anton Artemov <duke at openjdk.org> wrote:

>> Hi, please consider the following changes:
>> 
>> On AArch64, the `acquire` bool argument of the `safepoint_poll()` method is removed, as the load-acquire `ldar` instruction in the `safepoint_poll()` implementation is not needed completely. It was used for observing the disarmed value when VMThread was used to disarm the Java threads, but currently JavaThreads disarm themselves. 
>> 
>> Tested in tiers 1 - 4.
>
> Anton Artemov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8356556: Addressed reviewers' comments.

LGTM. Thanks

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25829#pullrequestreview-2935556664