On Fri, 24 May 2024 21:39:33 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 (ยง12.6) for that object."_ > > Brent Christian has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 69 commits: > > - Merge branch 'master' into refDocs2 > - add link to Thread.isAlive() > - small review tweaks; shorten MemoryConsistency links > - small grammar fixes > - new section for finalizer memviz > - add memviz bullet for finalization > - remove quotes from dequeue > - package spec updates, mostly about reference queues and dequeueing > - move reachability section before notification; update section header > - add details on use of reference queues; swap reachability/memviz sections > - ... and 59 more: https://git.openjdk.org/jdk/compare/7bf1989f...d7cbf0d3 src/java.base/share/classes/java/lang/ref/Reference.java line 491: > 489: * method is <b><i>unsuccessful</i></b> and returns false. > 490: * > 491: * <p><a href="package-summary.html#MemoryConsistency">Memory > consistency effects</a>: Note the `<a href="package-summary.thml#Foo>` syntax can be replaced with something like `{@link java.lang.ref##Foo}`. src/java.base/share/classes/java/lang/ref/Reference.java line 548: > 546: * This reachability is assured regardless of any optimizing > transformations > 547: * the virtual machine may perform that might otherwise allow the > object to > 548: * become unreachable (see {@jls 12.6.1}). Thus, the given object is > not I recommend replacing `(see {@jls 12.6.1})` with something like ` (see JLS {@jls 12.6.1})`, an idiom used elsewhere in core libs in formatting links into the JLS. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/16644#discussion_r1619921063 PR Review Comment: https://git.openjdk.org/jdk/pull/16644#discussion_r1619923554
