[15] RFR 8244420: Shenandoah: Ensure _disarmed_value offset < 128

[Roman Kennke]

Looks good.

Thanks,
Roman

> Please review this small patch that ensures per-thread's disarmed_value
> offset is under 126 bytes. The offset is encoded in nmethod entry
> barrier code stream as a disp8 on x86_64.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8244420
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8244420/webrev.00/
> 
> Test:
>   hotspot_gc_shenandoah
> 
> 
> Thanks,
> 
> -Zhengyu
>