RFR: 8275226: Shenandoah: Relax memory constraint for worker claiming tasks/ranges

[Aleksey Shipilev]

On Wed, 13 Oct 2021 15:33:23 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> I believe for the cases that there is no plain read on atomic variables, we can relax memory ordering constraints for claiming tasks/ranges by workers.
> 
> Test:
> - [x] hotspot_gc_shenandoah (fastdebug + release) on x86_64 and aarch64 Linux

Yes, all these look like plain atomic-counter CASes. Nothing seems to depend on their memory semantics.

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Marked as reviewed by shade (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5929