On Thu, 22 Feb 2024 01:42:17 GMT, Brent Christian <bchri...@openjdk.org> wrote:
>> Classes in the `java.lang.ref` package would benefit from an update to bring >> the spec in line with how the VM already behaves. The changes would focus on >> _happens-before_ edges at some key points during reference processing. >> >> A couple key things we want to be able to say are: >> - `Reference.reachabilityFence(x)` _happens-before_ reference processing >> occurs for 'x'. >> - `Cleaner.register()` _happens-before_ the Cleaner thread runs the >> registered cleaning action. >> >> This will bring Cleaner in line (or close) with the memory visibility >> guarantees made for finalizers in [JLS >> 17.4.5](https://docs.oracle.com/javase/specs/jls/se18/html/jls-17.html#jls-17.4.5): >> _"There is a happens-before edge from the end of a constructor of an object >> to the start of a finalizer (§12.6) for that object."_ > > Brent Christian has updated the pull request incrementally with one > additional commit since the last revision: > > Cleaner thread dequeue happens-before running cleaning action src/java.base/share/classes/java/lang/ref/Reference.java line 550: > 548: * <a href="package-summary.html#reachability"><em>strongly > reachable</em></a>. > 549: * This reachability is assured regardless of any optimizing > transformations > 550: * the VM may perform that might otherwise allow the object to become since "the virtual machine" is spelt out later in the documentation I think we should do the same here. Suggestion: * the virtual machine may perform that might otherwise allow the object to become ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/16644#discussion_r1498900890
