Re: [RFC PATCH 0/3] 9p: Further netfslib-related changes

[David Howells]

Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx> wrote:

> >  (1) Enable large folio support for 9p.  This is handled entirely by
> >      netfslib and is already supported in afs.  I wonder if we should limit
> >      the maximum folio size to 1MiB to match the maximum I/O size in the 9p
> >      protocol.
> 
> The limit depends on user's 'msize' 9p client option and on the 9p transport
> implementation. The hard limit with virtio transport for instance is currently
> just 500k (patches for virtio 4MB limit fetching dust unfortunately).

Okay.  Is that 500KiB or 512Kib?

> Would you see an advantage to limit folio size? I mean p9_client_read() etc.
> are automatically limiting the read/write chunk size accordingly.

For reads not so much, but for writes it would mean that a dirty folio is
either entirely written or entirely failed.  I don't know how important this
would be for the 9p usecases.

David