RFR: 8334060: Implementation of Late Barrier Expansion for G1 [v16]

[Kim Barrett]

On Fri, 6 Sep 2024 12:04:52 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

> > I was just thinking whether it is necessary to do these barriers for enums at all. They will most likely always reside in a different region/generation anyways, and will (but that may be wrong) never be collected.
> 
> As far as I understand, from a GC perspective enum instances are handled just like any other class instance, so I do not think there is any special GC barrier optimization opportunity for them. Maybe some GC expert can comment further on this or correct me if I am wrong.

@robcasloz is correct, the GCs don't have any special knowledge about enum instances.  They are ordinary objects,
though probably long-lived so will eventually migrate to the old generation.  Trying to do anything special with them
seems very unlikely to provide a benefit worth the costs involved.

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

PR Comment: https://git.openjdk.org/jdk/pull/19746#issuecomment-2334754544