RFR: 8265148: StackWatermarkSet being updated during AsyncGetCallTrace

[David Holmes]

On Thu, 27 May 2021 04:01:17 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

> 8265148: StackWatermarkSet being updated during AsyncGetCallTrace

Hi Leonid,

Someone familiar with Stackwatermarks will need to comment about the validity of doing this, my only comment is to document why it is being turned off.

Thanks,
David

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.

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