RFR: 8315559: Delay TempSymbol cleanup to avoid symbol table churn [v3]

[Oli Gillespie]

On Mon, 30 Oct 2023 21:20:28 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Oli Gillespie has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix failing tests
>>   
>>   TempNewSymbol now increments refcount again, messing with the
>>   expectations. This is not a complete fix, I will have to read the
>>   individual cases and make sure they are correct.
>
> test/hotspot/gtest/classfile/test_symbolTable.cpp line 40:
> 
>> 38:   int abccount = abc->refcount();
>> 39:   TempNewSymbol ss = abc;
>> 40:   // TODO: properly account for Symbol cleanup delay queue
> 
> I wonder if you can programmatically change the queue length to zero and keep these counts.
> 
> Then add a test with some loop of n being the queue length, and create n symbols and check that the first has been reclaimed?

Good idea. I have implemented this in the next commit, but I'm not sure what the idiomatic way to expose this value for testing is - I have just done it naively so far.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16398#discussion_r1377504954