RFR: 8191786: Thread-SMR hash table size should be dynamic

[Daniel D.Daugherty]

On Tue, 25 May 2021 01:10:37 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Small change to switch Thread-SMR's hash table from ResourceHashtable to KVHashtable
>> so that a variable sized hash table is used instead of a fixed size hash table (1031 elements).
>> Also refactor common hash table size calculation code into static hash_table_size()
>> function and call it from both places.
>> 
>> Test with Mach5 Tier[1-7] testing.
>
> Hi Dan,
> 
> What is the motivation behind this? What do we see happen with the current HT if we have too many threads? What will happen with the new HT when it has to resize - will we see a pause while that happens?
> 
> The mechanics of the change seem okay. A couple of queries on ergonomics choices.
> 
> Thanks,
> David

@dholmes-ora and @robehn - Thanks for the reviews!

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PR: https://git.openjdk.java.net/jdk/pull/4168