Hi Richard,

Unfortunately we have no plan for this activity. I’m not familiar with the 
problem so can’t estimate the time required to implement the functionality. Is 
this blocking you? As workaround I can prepare simple barriers implementation 
enough to run SerialGC.   

With best regards,

Sergey



> On 28 Nov 2022, at 13:03, Reingruber, Richard <richard.reingru...@sap.com> 
> wrote:
> 
> Dear ARM32 Maintainers, Boris, Sergey, [1]
> 
> ARM32 does not implement nmethod entry barriers (see 
> https://bugs.openjdk.org/browse/JDK-8291302).
> 
> This is actually a defect because nmethod entry barriers are a G1 requirement 
> where they are needed during concurrent marking to keep alive nmethod oop 
> constants as they are all weak oops[2].
> 
> I'd like to do a clean-up which removes redundant stackwalks from the G1 
> remark pause[3]. With nmethod entry barriers they are not necessary as they 
> do the same keep alive for oop constants of nmethods found on stack. Without 
> nmethod barriers (ARM32) these stackwalks are not sufficient though as every 
> nmethod that is called during concurrent marking needs to do the keep alive 
> for SATB.
> 
> Could you share your plans regarding the implementation of nmethod entry 
> barriers? How would you like me to handle ARM32 in the intended clean-up?
> 
> Thanks,
> Richard.
> 
> [1] found you on https://wiki.openjdk.org/display/HotSpot/Ports
> [2] https://bugs.openjdk.org/browse/JDK-8288970
> [3] https://github.com/openjdk/jdk/pull/11314

Reply via email to