On Fri, 17 Jun 2022 21:39:16 GMT, Maurizio Cimadamore <[email protected]>
wrote:
> This is a dependent PR containing a cleanup of the so called *heap sessions*.
> Heap sessions are used in two cases:
>
> * when a buffer segment is created, to keep the original buffer instance
> reachable
> * when a loader symbol lookup is created, to keep the classloader instance
> reachable
>
> Spinning new sessions in these cases seems unnecessary, and inconsistent with
> what we do for segments backed by on-heap arrays, whose session is set to the
> global session. In that case, it's up to the segment to keep the underlying
> array reachable. I think that's a better model.
>
> This patch adds the ability to attach Object references to native and mapped
> memory segments, so that we can attach loader/byte buffer instances to these
> segments, keeping them alive. This means that, in these cases we can go back
> to just use the global memory session, like we do for array segments.
>
> This simplifies the implementation, makes the documentation more consistent,
> and also simplifies the user model, as it removes a concept (of heap session)
> that is not really documented anywhere. In fact, the javadoc for
> MemorySegment::ofBuffer claims, (wrongly!) that the session of the resulting
> segment is the global session - but that's not the case.
src/java.base/share/classes/java/lang/foreign/SymbolLookup.java line 148:
> 146: * <p>
> 147: * The symbols obtained from the returned loader lookup are backed
> by the {@linkplain MemorySession#global() global session}.
> 148: * <p>
Does the spec update mean this should have a CSR?
-------------
PR: https://git.openjdk.org/jdk19/pull/39
