Do people follow GC research at all 'for fun'? Any places/sites/people to pay attention to for the latest and greatest goings-on that may show up in production x years from now?
Beware that you're gonna have to filter a lot! There's patch merging and very low detail implementation conversations. For example, you'd be pleased to know that G1 can now skip a guard in card-table clearing [4]. Don't ask me what is the card table and guards and why do you need to clear it, though.
One thing I'm looking for in GC advances is new hardware support for it in RISC-V J extension. There's gonna be memory tagging (helping security and memory management in GCs), and pointer masking (hardware support for what ZGC does under the hood)[5]. But we're probably a good 5 years away from seeing that in real life, if ever.
[1] https://mail.openjdk.org/pipermail/loom-dev/
[2] https://mail.openjdk.org/pipermail/hotspot-gc-dev/
[3] https://mail.openjdk.org/mailman/listinfo
[4] https://mail.openjdk.org/pipermail/hotspot-gc-dev/2023-March...
[5] https://github.com/riscv/riscv-j-extension/blob/master/point...
Besides the JVM resources linked by others, I found Richard Jones's "Garbage Collection Handbook" to be a decent introduction for background [1]. The Go team has written a bunch about their GC approach [2] - it is really interesting to see how it compares to the various options in the JVM and under which scenario you might prefer one or the other. And occasionally there are interesting articles on arxiv.