> On Mar 16, 2023, at 14:06, David Howells <dhowells@xxxxxxxxxx> wrote: > > Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > >> 1) This is code that is common to the client and the server. Why are we >> adding unused 3 bvec slots to every client RPC call? > > Fair point, but I'm trying to avoid making four+ sendmsg calls in nfsd rather > than one. Add an enum iter_type for ITER_ITER ? :-) Otherwise, please just split these functions into one for knfsd and a separate one for the client. > >> 2) It obfuscates the existence of these bvec slots. > > True, it'd be nice to find a better way to do it. Question is, can the client > make use of MSG_SPLICE_PAGES also? The requirement for O_DIRECT support means we get the stable write issues with added extra spicy sauce. > >> 3) knfsd may use splice_direct_to_actor() in order to avoid copying the page >> cache data into private buffers (it just takes a reference to the >> pages). Using MSG_SPLICE_PAGES will presumably require it to protect those >> pages against further writes while the socket is referencing them. > > Upstream sunrpc is using sendpage with TCP. It already has that issue. > MSG_SPLICE_PAGES is a way of doing sendpage through sendmsg. Fair enough. I do seem to remember a schism with the knfsd developers over that issue. _________________________________ Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
