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

[Patricio Chilano Mateo]

On Mon, 16 Jun 2025 13:03:11 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.

LGTM, thanks.

src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp line 557:

> 555: 
> 556: void MacroAssembler::safepoint_poll(Label& slow_path, bool at_return, bool in_nmethod, Register tmp) {
> 557: 

Nit: extra line not needed.

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Marked as reviewed by pchilanomate (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25829#pullrequestreview-2933828617
PR Review Comment: https://git.openjdk.org/jdk/pull/25829#discussion_r2151104532