On Thu, Jan 09, 2025 at 11:21:02AM +0100, Jan Kara wrote: > Hi! > > On Wed 08-01-25 22:23:16, Lorenzo Stoakes via Lsf-pc wrote: > > A future where we unify anonymous and file-backed memory mappings would be > > one in which a reflinks were implemented at a general level rather than, as > > they are now, implemented individually within file systems. > > > > I'd like to discuss how feasible doing so might be, whether this is a sane > > line of thought at all, and how a roadmap for working towards the > > elimination of anon_vma as it stands might look. > > As you can imagine this has been discussed in the past and some folks are > very interested in saving page cache memory for some heavily reflinked > container setups or for various FUSE filesystems. So if someone manages to > come up with a feasible design, the usecases are there. I think reading > e.g. [1] and comments below it is a good preparation for the session to get > some idea what challenges are there :). Oh I certainly imagined that it had :) Perhaps you are volunteering to assist me from an fs point of view on this Jan? ;) Thanks for the link, I will have a read! I am certainly aware of just how huge a topic this is, as LSF is all about discussion it's really one I wanted to reignite and to see where we stand and how we might move forward. It's a bug bear of mine for various reasons (mostly around the locking, memory consumption and complexity concerns with anon_vma), and something I certainly hope to do something on - but over the very long term I suspect - should work on this be feasible. > > Honza > > [1] https://lwn.net/Articles/717950/ > > > > -- > Jan Kara <jack@xxxxxxxx> > SUSE Labs, CR Thanks!
