RFR: 8319797: Recursive lightweight locking: Runtime implementation [v6]

[Coleen Phillimore]

On Thu, 23 Nov 2023 07:38:49 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Update: I didn't see an explicit test case for overflowing the lock stack.
>> Do you plan to add one?
>
> Sure. They are generally tricky, you usually need to tell the compiler not to do stuff like eliding locks, and inline methods. I will attempt to write tests both for -Xint and the compiler that tests both recursive and normal full lock stack. (The recursive tests requires the platform to implement recursive lightweight for it to effectively test anything)

I wrote a little test case just now.  Maybe deciding which object should cause inflation can be tuned with some benchmarking results if we find some degenerate case?  Maybe the top lock should be inflated since that might be the one that causes the stack to overflow?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16606#discussion_r1459807878