RFR: 8373096: JFR leak profiler: path-to-gc-roots search should be non-recursive [v7]

[Thomas Stuefe]

On Thu, 18 Dec 2025 20:26:14 GMT, Robert Toyonaga <duke at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   do strides for arrays
>
> src/hotspot/share/jfr/leakprofiler/chains/dfsClosure.cpp line 134:
> 
>> 132:             ProbeStackItem psi2 = psi;
>> 133:             psi2.chunk ++;
>> 134:             _probe_stack.push(psi2);
> 
> Could checking the marked status of `pointee` now become a problem ? To accomplish the striding, the same `pointee` needs to be revisited with the new chunk count to evaluate the next range.  However, the next time it's popped off the stack, it will get skipped over on line 108 since it's already been marked. 
> 
> `TestJcmdDumpPathToGCRootsBFSDFS.java` passes even after I add `assert(psi.chunk==0 )` in this block after line 122, which might indicate only the first range of each array is ever getting evaluated.

Yes, I saw this yesterday too. The current version does not work. I am rethinking the solution.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28659#discussion_r2633959011