Hi Chuck,
On 01/23/2017 03:52 PM, Chuck Lever wrote:
> Pad optimization is changed by echoing into
> /proc/sys/sunrpc/rdma_pad_optimize. This is a global setting,
> affecting all RPC-over-RDMA connections to all servers.
>
> The marshaling code picks up that value and uses it for decisions
> about how to construct each RPC-over-RDMA frame. Having it change
> suddenly in mid-operation can result in unexpected failures. And
> some servers a client mounts might need chunk round-up, while
> others don't.
>
> So instead, copy the pad_optimize setting into each connection's
> rpcrdma_ia when the transport is created, and use the copy, which
> can't change during the life of the connection, instead.
Does the rdma_pad_optimize option have documentation somewhere that needs to be updated to describe the new behavior?
Anna
>
> This also removes a hack: rpcrdma_convert_iovs was using
> the remote-invalidation-expected flag to predict when it could leave
> out Write chunk padding. This is because the Linux server handles
> implicit XDR padding on Write chunks correctly, and only Linux
> servers can set the connection's remote-invalidation-expected flag.
>
> It's more sensible to use the pad optimization setting instead.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> net/sunrpc/xprtrdma/rpc_rdma.c | 28 ++++++++++++++--------------
> net/sunrpc/xprtrdma/verbs.c | 1 +
> net/sunrpc/xprtrdma/xprt_rdma.h | 1 +
> 3 files changed, 16 insertions(+), 14 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
> index a524d3c..c634f0f 100644
> --- a/net/sunrpc/xprtrdma/rpc_rdma.c
> +++ b/net/sunrpc/xprtrdma/rpc_rdma.c
> @@ -186,9 +186,9 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
> */
>
> static int
> -rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos,
> - enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg,
> - bool reminv_expected)
> +rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
> + unsigned int pos, enum rpcrdma_chunktype type,
> + struct rpcrdma_mr_seg *seg)
> {
> int len, n, p, page_base;
> struct page **ppages;
> @@ -229,14 +229,15 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
> /* When encoding a Read chunk, the tail iovec contains an
> * XDR pad and may be omitted.
> */
> - if (type == rpcrdma_readch && xprt_rdma_pad_optimize)
> + if (type == rpcrdma_readch && r_xprt->rx_ia.ri_implicit_roundup)
> return n;
>
> - /* When encoding the Write list, some servers need to see an extra
> - * segment for odd-length Write chunks. The upper layer provides
> - * space in the tail iovec for this purpose.
> + /* When encoding a Write chunk, some servers need to see an
> + * extra segment for non-XDR-aligned Write chunks. The upper
> + * layer provides space in the tail iovec that may be used
> + * for this purpose.
> */
> - if (type == rpcrdma_writech && reminv_expected)
> + if (type == rpcrdma_writech && r_xprt->rx_ia.ri_implicit_roundup)
> return n;
>
> if (xdrbuf->tail[0].iov_len) {
> @@ -291,7 +292,8 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
> if (rtype == rpcrdma_areadch)
> pos = 0;
> seg = req->rl_segments;
> - nsegs = rpcrdma_convert_iovs(&rqst->rq_snd_buf, pos, rtype, seg, false);
> + nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
> + rtype, seg);
> if (nsegs < 0)
> return ERR_PTR(nsegs);
>
> @@ -353,10 +355,9 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
> }
>
> seg = req->rl_segments;
> - nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf,
> + nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
> rqst->rq_rcv_buf.head[0].iov_len,
> - wtype, seg,
> - r_xprt->rx_ia.ri_reminv_expected);
> + wtype, seg);
> if (nsegs < 0)
> return ERR_PTR(nsegs);
>
> @@ -421,8 +422,7 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
> }
>
> seg = req->rl_segments;
> - nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf, 0, wtype, seg,
> - r_xprt->rx_ia.ri_reminv_expected);
> + nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
> if (nsegs < 0)
> return ERR_PTR(nsegs);
>
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 11d0774..2a6a367 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -208,6 +208,7 @@
>
> /* Default settings for RPC-over-RDMA Version One */
> r_xprt->rx_ia.ri_reminv_expected = false;
> + r_xprt->rx_ia.ri_implicit_roundup = xprt_rdma_pad_optimize;
> rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
> wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
>
> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
> index e35efd4..c137154 100644
> --- a/net/sunrpc/xprtrdma/xprt_rdma.h
> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h
> @@ -75,6 +75,7 @@ struct rpcrdma_ia {
> unsigned int ri_max_inline_write;
> unsigned int ri_max_inline_read;
> bool ri_reminv_expected;
> + bool ri_implicit_roundup;
> enum ib_mr_type ri_mrtype;
> struct ib_qp_attr ri_qp_attr;
> struct ib_qp_init_attr ri_qp_init_attr;
>
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