On Wed, 19 Mar 2025 21:35:53 GMT, Chen Liang <li...@openjdk.org> wrote:

>> The recent patch #23866 makes calling `ClassValue::remove()` from 
>> `ClassValue::computeValue()` end up in infinite loops while fixing the stale 
>> value risk from the method.
>> 
>> The proposed fix is to preserve the stale value risk fix, and update the 
>> remove-from-compute behavior from the original designated no-op behavior to 
>> throwing an exception, as the original behavior conflicts with the stale 
>> value fix.
>> 
>> The implementation track the owner thread in promises (accessed in locked 
>> section); as a result, we can fail-fast on recursive removals from 
>> `computeValue`. I did not choose to use `ThreadTracker` as it is designed 
>> for single tracker and multiple threads, while this case here sees often 
>> just one thread, and the threads outlive the promise objects.
>> 
>> Also updated the API specs for `remove` to more concisely describe the 
>> memory effects. Please review the associated CSR as well.
>
> Chen Liang has updated the pull request with a new target base due to a merge 
> or a rebase. The incremental webrev excludes the unrelated changes brought in 
> by the merge/rebase. The pull request contains four additional commits since 
> the last revision:
> 
>  - Use identity of thread, some optimizations for single thread case
>  - Merge branch 'master' of https://github.com/openjdk/jdk into 
> fix/classvalue-compute-remove
>  - Track threads on the promise for cheap reentrancy checks
>  - 8351996: Alternative way to ensure no stale values for ClassValue::remove

I noticed this one about `CV_InjectedInvoker`, just have not throughoutly 
investigated its usage pattern yet.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/24043#issuecomment-2743522606

Reply via email to