+1. We don’t bump this dependency outside of JDK versions so being in tree actually makes it easier for us to support newer JDK versions
> On Dec 10, 2025, at 8:41 AM, Aleksey Yeshchenko <[email protected]> wrote: > > +1 to bringing it in-tree. > >> On 10 Dec 2025, at 13:32, Ekaterina Dimitrova <[email protected]> wrote: >> >> +1 if there are volunteers to do the work, that’s great >> >> On Wed, 10 Dec 2025 at 8:20, Dmitry Konstantinov <[email protected] >> <mailto:[email protected]>> wrote: >>> +1 >>> >>> On Wed, 10 Dec 2025 at 13:12, Brandon Williams <[email protected] >>> <mailto:[email protected]>> wrote: >>>> Sounds good to me, let's bring it in. +1 >>>> >>>> Kind Regards, >>>> Brandon >>>> >>>> On Wed, Dec 10, 2025 at 6:47 AM Josh McKenzie <[email protected] >>>> <mailto:[email protected]>> wrote: >>>> > >>>> > I think we should bring jamm in-tree. >>>> > >>>> > I spoke with Jonathan about this and he's good with either it being a >>>> > single-shot donation to being in-tree on trunk or us going the more >>>> > formal route of an ASF donation as a subproject in the C* ecosystem. I >>>> > prefer the former as it'll make it easier to keep it up to date as we >>>> > add new JDK support, verify CI, and we can still release it separately >>>> > as another build target. >>>> > >>>> > Context: We rely on the jamm library to determine object sizes on heap >>>> > and trigger some operations based on that. >>>> > - jamm: https://github.com/jbellis/jamm >>>> > - ObjectSizes.java in cassandra: >>>> > https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/utils/ObjectSizes.java >>>> > >>>> > The jamm project is in a good place from a hygiene perspective; Benjamin >>>> > did a ton of work getting it up to snuff for JDK17. I have a PR for >>>> > JDK21 support over there (link) but was able to work around even needing >>>> > that by signaling to jamm not to calculate w/compressedOops, though in >>>> > retrospect that documentation needs to be updated to reflect the >>>> > coupling with using genZGC: >>>> > https://github.com/jmckenzie-dev/cassandra/blob/jdk21_support/build.xml#L343-L344 >>>> > >>>> > So. What do we think? >>> >>> >>> >>> -- >>> Dmitry Konstantinov >
