Hi Bruce-
Here is part of what we discussed recently about trying to align
pages in NFS WRITE requests so that splice can be used. This
series updates server-side RPC and svcrdma to ensure that an
aligned xdr_buf::pages array is presented to NFSD, which is then
converted into an aligned rq_vec for the VFS layer.
The next step would be to look at how to make the best use of the
aligned rq_vec. My naive thought is that where there is a PAGE_SIZE
entry in rq_vec and there is no page in the file's page cache at
that offset, the transport-provided page can be flipped into place.
Might work for replacing whole pages as well, but baby steps first.
This series has been exercised a bit with both TCP and RDMA, but no
guarantees that it is completely bug-free. NFSv4 compounds with
multiple WRITE payloads on RDMA are treated like TCP: the RPC
message is contained in an unstructured stream of unaligned pages.
Comments encouraged.
---
Chuck Lever (6):
SUNRPC: Capture value of xdr_buf::page_base
SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
SUNRPC: svc_fill_write_vector() must handle non-zero page_bases
NFSD: Add a transport hook for pulling argument payloads
svcrdma: Pull Read chunks in ->xpo_argument_payload
fs/nfsd/nfs3proc.c | 3 +-
fs/nfsd/nfs3xdr.c | 16 +--
fs/nfsd/nfs4proc.c | 3 +-
fs/nfsd/nfs4xdr.c | 6 +
fs/nfsd/nfsproc.c | 3 +-
fs/nfsd/nfsxdr.c | 13 +--
fs/nfsd/xdr.h | 2 +-
fs/nfsd/xdr3.h | 2 +-
include/linux/sunrpc/svc.h | 6 +-
include/linux/sunrpc/svc_rdma.h | 8 ++
include/linux/sunrpc/svc_xprt.h | 3 +
include/trace/events/rpcrdma.h | 26 +++++
include/trace/events/sunrpc.h | 20 +++-
net/sunrpc/svc.c | 38 +++++--
net/sunrpc/svcsock.c | 8 ++
net/sunrpc/xdr.c | 32 +++---
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 37 +++++-
net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++---
net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 +
19 files changed, 292 insertions(+), 74 deletions(-)
--
Chuck Lever
