On Wed, Jun 12, 2013 at 10:16 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > On Wed, Jun 12, 2013 at 09:51:09PM +0530, Sandeep Joshi wrote: > > Splice can be implemented independent of RDMA. It is supposed to > > transfer > > pages between two file descriptors. I found some postings on lkml from > > 2006 where Linus says it is quite possible to splice from a socket to a > > file. > > > > See the paragraph: > > " For filesystems, splice support tends to be really easy (both read and > > write). For other things, it depends a bit. But unlike sendfile(), it > > really is quite possible to splice _from_ a socket too, not just _to_ a > > socket. But no, that case hasn't been written yet." > > http://yarchive.net/comp/linux/splice.html > > > > Larry McVoy's 1997 proposal for adding splice support to the kernel can > > be > > read at > > ftp.tux.org/pub/sites/ftp.bitmover.com/pub/*splice*.*ps*.gz<http://ftp.tux.org/pub/sites/ftp.bitmover.com/pub/splice.ps.gz> > > > > Perhaps I should have opened this thread on lkml to determine if splice > > from socket to file is still feasible.. > > Right, the thing is, nfsd reads the rpc request from the socket into its > own buffers before it parses it. If you want to move the data directly > out of the network buffers into the page cache, then you have to know at > what point the write data starts in the request--which I believe will > mean doing the xdr parsing (and gss decryption if necessary) as the > request comes in off the wire. > > That sounds like a lot of work and even if you have someone willing to > do the work they'd also need to justify that it's worth it. > > RDMA may have some protocol support that simplifies this, I don't know. > > --b. Hi Bruce, > nfsd reads the rpc request from the socket into its own buffers before it parses it. I am not intimate with the gss code but do you think the svc_rqst->rq_pages[] can be spliced ? -Sandeep -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
