[crac] RFR: RCU Lock - RW lock with very lightweight read- and heavyweight write-locking

[Radim Vansa]

On Wed, 12 Apr 2023 08:57:48 GMT, Radim Vansa <duke at openjdk.org> wrote:

> This implementation is suitable for uses where the write-locking happens very rarely (if at all), as in the case of CRaC checkpoint, and we don't want to slow down regular access to the protected resource.

After implementing this I realized that it could be possible to implement the check using `Thread.getAllStackTraces()` and process the stacks in Java; that's even heavier, though.

I will yet explore extending implementation with more dynamic list of methods; such implementation could let us use only one instance of RCULock in the VM.

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PR Comment: https://git.openjdk.org/crac/pull/58#issuecomment-1504920463