RFR: 8318682: SA decoding of scalar replaced objects is broken [v5]

[Chris Plummer]

On Wed, 17 Jan 2024 19:44:38 GMT, Tom Rodriguez <never at openjdk.org> wrote:

>> test/hotspot/jtreg/ProblemList-generational-zgc.txt line 108:
>> 
>>> 106: serviceability/sa/sadebugd/ClhsdbAttachToDebugServer.java     8307393   generic-all
>>> 107: serviceability/sa/sadebugd/ClhsdbTestConnectArgument.java     8307393   generic-all
>>> 108: serviceability/sa/ClhsdbTestAllocationMerge.java              8307393   generic-all
>> 
>> Do you need to add TestDebugInfoDecode.java?
>
> No.  ClhsdbTestAllocationMerge is using `jstack -v` which doesn't work with ZGC because the `-v` part needs to iterate the heap looking for AbstractQueuedSynchronizers which doesn't work with ZGC and the SA.

It's not -v that is making it do that. It does it without -v also. It can be a very slow operation, and I recently was running into cases where even after 10 minutes it was not done, so I gave up waiting. I'm about to file a CR to make it so it does not do that by default, and add a -l argument to optionally enable it. This will make it consistent with what bin/jstack is doing. I already have the fix ready. Just need to get the CR filed and and publish the PR.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17407#discussion_r1456400105