[$] A discussion on folios

A few weeks ago, Matthew Wilcox might have guessed that his session
at the 2021 Linux
Plumbers Conference would be focused rather differently. But, as we reported earlier in September, his folio patch set ran into some, perhaps
unexpected, opposition and, ultimately, did not land in the mainline for
5.15. Instead of discussing how to use folios as part
of the File
Systems microconference, he led a discussion that was, at least in part, on the
path forward for them.