Hacker News Reader

I didn't know about fully concurrent root scanning, thank you!

How does root scanning work wrt to Loom? Are stacks of virtual threads treated as roots? I guess there is no other option?

View on HN

No, virtual thread stacks are not roots! This is one of the main design highlights of the current Loom implementation. In fact, at least currently, the VM doesn't maintain any list of virtual threads at all. They are just Java objects, but the GC does treat them specially.

Interesting! In what way are they handled specially?

Unlike any other object, the location of references on a stack can change dynamically, so the GC needs to recognise those objects and walk their references differently. There are other subtleties, too.

Reply on news.ycombinator.com