Re: RFR: 8314480: Memory ordering spec updates in java.lang.ref [v25]
On Thu, 25 Apr 2024 08:25:39 GMT, Viktor Klang wrote:
>> Brent Christian has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> package spec updates, mostly about reference queues and dequeueing
>
> src/java.base/share/classes/java/lang/ref/package-info.java line 153:
>
>> 151: * The enqueueing of a reference (by the garbage collector, or
>> 152: * by a successful call to {@link Reference#enqueue})
>> happens-before
>> 153: * the reference is removed from the queue (dequeued).
>
> @bchristi-git I wonder if it makes sense to use the same style when referring
> to "dequeue", so either always within quotes or only using em (see
> line 108)
Sure; I'll remove the quotes.
-
PR Review Comment: https://git.openjdk.org/jdk/pull/16644#discussion_r1580238810
Re: RFR: 8314480: Memory ordering spec updates in java.lang.ref [v25]
On Wed, 24 Apr 2024 23:15:45 GMT, Brent Christian 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:
>
> package spec updates, mostly about reference queues and dequeueing
src/java.base/share/classes/java/lang/ref/package-info.java line 153:
> 151: * The enqueueing of a reference (by the garbage collector, or
> 152: * by a successful call to {@link Reference#enqueue})
> happens-before
> 153: * the reference is removed from the queue (dequeued).
@bchristi-git I wonder if it makes sense to use the same style when referring
to "dequeue", so either always within quotes or only using em (see
line 108)
-
PR Review Comment: https://git.openjdk.org/jdk/pull/16644#discussion_r1579082626
Re: RFR: 8314480: Memory ordering spec updates in java.lang.ref [v25]
> 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: package spec updates, mostly about reference queues and dequeueing - Changes: - all: https://git.openjdk.org/jdk/pull/16644/files - new: https://git.openjdk.org/jdk/pull/16644/files/cc21d296..16fcc764 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=16644&range=24 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16644&range=23-24 Stats: 15 lines in 1 file changed: 0 ins; 3 del; 12 mod Patch: https://git.openjdk.org/jdk/pull/16644.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16644/head:pull/16644 PR: https://git.openjdk.org/jdk/pull/16644
