RFR: 8265148: StackWatermarkSet being updated during AsyncGetCallTrace

[Leonid Mesnik]

On Thu, 27 May 2021 23:07:02 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> 8265148: StackWatermarkSet being updated during AsyncGetCallTrace
>
> src/hotspot/share/prims/forte.cpp line 326:
> 
>> 324:     int loop_count;
>> 325:     int loop_max = MaxJavaStackTraceDepth * 2;
>> 326:     RegisterMap map(thread, false, false);
> 
> Can we add some comments as to what the false parameters mean please.
> 
> RegisterMap map(thread, false /* no update */, false /*no stackwatermark frame processing */);
> 
> Though it may be that a more elaborate block comment is needed to explain why we don't want stackwatermark frame processing.

Let me check with Erik if it makes sense to put more generic comments about the usage of stackwatermark frame processing in RegisterMap, frames etc.  They can't be updated in an arbitrary thread state. It makes sense describe this info in stackwatermarking.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4217