[$] Large folios, swap, and FS-Cache

David Howells wanted to discuss swap handling in light of multi-page foliosin a combined storage, filesystem, and memory-management session atthe 2024 Linux Storage,Filesystem, Memory Management, and BPF Summit. Swapping has always beendone with a one-to-one mapping of memory pages to swap slots, he said, butswapping multi-page folios breaks that assumption. He wondered if it wouldmake sense to use filesystem techniques to track swapped-out folios.