[$] Flexible data placement

At the 2025 Linux Storage, Filesystem, MemoryManagement, and BPF Summit (LSFMM+BPF) Kanchan Joshi and Keith Busch led acombined storage and filesystem session on data placement, which concernshow the data on a storage device is actually written. In a discussionthat hearkened back to previous summits, the idea is to give hints to enterprise-classSSDs to help them make better choices on where the data should go; hintingwas most recently discussed at the summit in 2023. If SSDs cangroup data with similar lifetimes together, it can lead to longer life forthe devices, but there is a need to work out the details.