On Tue, Nov 27, 2018 at 11:11:35AM -0500, Chuck Lever wrote:
> o Select the R_key to invalidate while the CPU cache still contains
> the received RPC Call transport header, rather than waiting until
> we're about to send the RPC Reply.
>
> o Choose Send With Invalidate if there is exactly one distinct R_key
> in the received transport header. If there's more than one, the
> client will have to perform local invalidation after it has
> already waited for remote invalidation.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> Hi-
>
> Please consider this NFS server-side patch for v4.21.
OK, thanks, applying.
(By the way, I appreciate it if patch submissions have
bfields@xxxxxxxxxxxx on the To: line, my filters handle that a little
differently than mailing list traffic.)
--b.
>
>
> include/linux/sunrpc/svc_rdma.h | 1
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 63 +++++++++++++++++++++++++++++++
> net/sunrpc/xprtrdma/svc_rdma_sendto.c | 53 ++++++--------------------
> 3 files changed, 77 insertions(+), 40 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index e6e2691..7e22681 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -135,6 +135,7 @@ struct svc_rdma_recv_ctxt {
> u32 rc_byte_len;
> unsigned int rc_page_count;
> unsigned int rc_hdr_count;
> + u32 rc_inv_rkey;
> struct page *rc_pages[RPCSVC_MAXPAGES];
> };
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index b24d5b8..828b149 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -485,6 +485,68 @@ static __be32 *xdr_check_reply_chunk(__be32 *p, const __be32 *end)
> return p;
> }
>
> +/* RPC-over-RDMA Version One private extension: Remote Invalidation.
> + * Responder's choice: requester signals it can handle Send With
> + * Invalidate, and responder chooses one R_key to invalidate.
> + *
> + * If there is exactly one distinct R_key in the received transport
> + * header, set rc_inv_rkey to that R_key. Otherwise, set it to zero.
> + *
> + * Perform this operation while the received transport header is
> + * still in the CPU cache.
> + */
> +static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
> + struct svc_rdma_recv_ctxt *ctxt)
> +{
> + __be32 inv_rkey, *p;
> + u32 i, segcount;
> +
> + ctxt->rc_inv_rkey = 0;
> +
> + if (!rdma->sc_snd_w_inv)
> + return;
> +
> + inv_rkey = xdr_zero;
> + p = ctxt->rc_recv_buf;
> + p += rpcrdma_fixed_maxsz;
> +
> + /* Read list */
> + while (*p++ != xdr_zero) {
> + p++; /* position */
> + if (inv_rkey == xdr_zero)
> + inv_rkey = *p;
> + else if (inv_rkey != *p)
> + return;
> + p += 4;
> + }
> +
> + /* Write list */
> + while (*p++ != xdr_zero) {
> + segcount = be32_to_cpup(p++);
> + for (i = 0; i < segcount; i++) {
> + if (inv_rkey == xdr_zero)
> + inv_rkey = *p;
> + else if (inv_rkey != *p)
> + return;
> + p += 4;
> + }
> + }
> +
> + /* Reply chunk */
> + if (*p++ != xdr_zero) {
> + segcount = be32_to_cpup(p++);
> + for (i = 0; i < segcount; i++) {
> + if (inv_rkey == xdr_zero)
> + inv_rkey = *p;
> + else if (inv_rkey != *p)
> + return;
> + p += 4;
> + }
> + }
> +
> + ctxt->rc_inv_rkey = be32_to_cpu(inv_rkey);
> +}
> +
> /* On entry, xdr->head[0].iov_base points to first byte in the
> * RPC-over-RDMA header.
> *
> @@ -746,6 +808,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
> svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
> return ret;
> }
> + svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
>
> p += rpcrdma_fixed_maxsz;
> if (*p != xdr_zero)
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index 8602a5f..d48bc6d 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -484,32 +484,6 @@ static void svc_rdma_get_write_arrays(__be32 *rdma_argp,
> *reply = NULL;
> }
>
> -/* RPC-over-RDMA Version One private extension: Remote Invalidation.
> - * Responder's choice: requester signals it can handle Send With
> - * Invalidate, and responder chooses one rkey to invalidate.
> - *
> - * Find a candidate rkey to invalidate when sending a reply. Picks the
> - * first R_key it finds in the chunk lists.
> - *
> - * Returns zero if RPC's chunk lists are empty.
> - */
> -static u32 svc_rdma_get_inv_rkey(__be32 *rdma_argp,
> - __be32 *wr_lst, __be32 *rp_ch)
> -{
> - __be32 *p;
> -
> - p = rdma_argp + rpcrdma_fixed_maxsz;
> - if (*p != xdr_zero)
> - p += 2;
> - else if (wr_lst && be32_to_cpup(wr_lst + 1))
> - p = wr_lst + 2;
> - else if (rp_ch && be32_to_cpup(rp_ch + 1))
> - p = rp_ch + 2;
> - else
> - return 0;
> - return be32_to_cpup(p);
> -}
> -
> static int svc_rdma_dma_map_page(struct svcxprt_rdma *rdma,
> struct svc_rdma_send_ctxt *ctxt,
> struct page *page,
> @@ -672,7 +646,7 @@ static void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
> *
> * RDMA Send is the last step of transmitting an RPC reply. Pages
> * involved in the earlier RDMA Writes are here transferred out
> - * of the rqstp and into the ctxt's page array. These pages are
> + * of the rqstp and into the sctxt's page array. These pages are
> * DMA unmapped by each Write completion, but the subsequent Send
> * completion finally releases these pages.
> *
> @@ -680,32 +654,31 @@ static void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
> * - The Reply's transport header will never be larger than a page.
> */
> static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
> - struct svc_rdma_send_ctxt *ctxt,
> - __be32 *rdma_argp,
> + struct svc_rdma_send_ctxt *sctxt,
> + struct svc_rdma_recv_ctxt *rctxt,
> struct svc_rqst *rqstp,
> __be32 *wr_lst, __be32 *rp_ch)
> {
> int ret;
>
> if (!rp_ch) {
> - ret = svc_rdma_map_reply_msg(rdma, ctxt,
> + ret = svc_rdma_map_reply_msg(rdma, sctxt,
> &rqstp->rq_res, wr_lst);
> if (ret < 0)
> return ret;
> }
>
> - svc_rdma_save_io_pages(rqstp, ctxt);
> + svc_rdma_save_io_pages(rqstp, sctxt);
>
> - ctxt->sc_send_wr.opcode = IB_WR_SEND;
> - if (rdma->sc_snd_w_inv) {
> - ctxt->sc_send_wr.ex.invalidate_rkey =
> - svc_rdma_get_inv_rkey(rdma_argp, wr_lst, rp_ch);
> - if (ctxt->sc_send_wr.ex.invalidate_rkey)
> - ctxt->sc_send_wr.opcode = IB_WR_SEND_WITH_INV;
> + if (rctxt->rc_inv_rkey) {
> + sctxt->sc_send_wr.opcode = IB_WR_SEND_WITH_INV;
> + sctxt->sc_send_wr.ex.invalidate_rkey = rctxt->rc_inv_rkey;
> + } else {
> + sctxt->sc_send_wr.opcode = IB_WR_SEND;
> }
> dprintk("svcrdma: posting Send WR with %u sge(s)\n",
> - ctxt->sc_send_wr.num_sge);
> - return svc_rdma_send(rdma, &ctxt->sc_send_wr);
> + sctxt->sc_send_wr.num_sge);
> + return svc_rdma_send(rdma, &sctxt->sc_send_wr);
> }
>
> /* Given the client-provided Write and Reply chunks, the server was not
> @@ -809,7 +782,7 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
> }
>
> svc_rdma_sync_reply_hdr(rdma, sctxt, svc_rdma_reply_hdr_len(rdma_resp));
> - ret = svc_rdma_send_reply_msg(rdma, sctxt, rdma_argp, rqstp,
> + ret = svc_rdma_send_reply_msg(rdma, sctxt, rctxt, rqstp,
> wr_lst, rp_ch);
> if (ret < 0)
> goto err1;
