On Sat, 24 Aug 2024, Mike Snitzer wrote: > + > +6. Why is having the client perform a server-side file OPEN, without > + using RPC, beneficial? Is the benefit pNFS specific? > + > + Avoiding the use of XDR and RPC for file opens is beneficial to > + performance regardless of whether pNFS is used. However adding a > + requirement to go over the wire to do an open and/or close ends up > + negating any benefit of avoiding the wire for doing the I/O itself > + when we’re dealing with small files. There is no benefit to replacing > + the READ or WRITE with a new open and/or close operation that still > + needs to go over the wire. I don't think the above is correct. The current code still does a normal NFSv4 OPEN or NFSv3 GETATTR when then client opens a file. Only the READ/WRITE/COMMIT operations are avoided. While I'm not advocating for an over-the-wire request to map a filehandle to a struct nfsd_file*, I don't think you can convincingly argue against it without concrete performance measurements. NeilBrown
