[aarch64-port-dev ] Question about ISB usage in the aarch64 port

[Nick Gasson]

On 28/11/2019 22:02, Andrew Haley wrote:
>> BTW: should we change aarch64 to use this scheme too?
> 
> Not unless we have a reason. I had a look and there seemed to be no advantage.
> 

I don't think it helps on AArch64: that 
OrderAccess::cross_modifying_fence() is only called when a thread is 
about to return from the safepoint handler. But it's possible for a 
safepoint with code patching to happen in the background while a thread 
is in native code, in which case we still need to do an ISB when 
returning to Java.

I'm not sure how other ports that need a serialising instruction handle 
this?


Thanks,
Nick