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[68.61.232.219]) by smtp.gmail.com with ESMTPSA id e66sm1714343qkd.129.2020.03.19.08.21.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Mar 2020 08:21:12 -0700 (PDT) Received: from klimt.1015granger.net (klimt.1015granger.net [192.168.1.55]) by gateway.1015granger.net (8.14.7/8.14.7) with ESMTP id 02JFLAEH011172; Thu, 19 Mar 2020 15:21:10 GMT Subject: [PATCH RFC 09/11] svcrdma: Support multiple READ payloads when pulling up From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Thu, 19 Mar 2020 11:21:10 -0400 Message-ID: <20200319152110.16298.9209.stgit@klimt.1015granger.net> In-Reply-To: <20200319150136.16298.68813.stgit@klimt.1015granger.net> References: <20200319150136.16298.68813.stgit@klimt.1015granger.net> User-Agent: StGit/0.22 MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org When counting the number of SGEs needed to construct a Send request, do not count READ payloads. And, when copying the Reply message into the pull-up buffer, READ payloads are not to be copied to the Send buffer. Signed-off-by: Chuck Lever --- include/trace/events/rpcrdma.h | 15 ++- net/sunrpc/xprtrdma/svc_rdma_sendto.c | 186 ++++++++++++++++++++------------- 2 files changed, 121 insertions(+), 80 deletions(-) diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h index 9238d233f8cf..ff2d943d1540 100644 --- a/include/trace/events/rpcrdma.h +++ b/include/trace/events/rpcrdma.h @@ -1641,20 +1641,25 @@ TRACE_EVENT(svcrdma_dma_map_rwctx, TRACE_EVENT(svcrdma_send_pullup, TP_PROTO( - unsigned int len + unsigned int hdrlen, + unsigned int msglen ), - TP_ARGS(len), + TP_ARGS(hdrlen, msglen), TP_STRUCT__entry( - __field(unsigned int, len) + __field(unsigned int, hdrlen) + __field(unsigned int, msglen) ), TP_fast_assign( - __entry->len = len; + __entry->hdrlen = hdrlen; + __entry->msglen = msglen; ), - TP_printk("len=%u", __entry->len) + TP_printk("hdr=%u msg=%u (total %u)", + __entry->hdrlen, __entry->msglen, + __entry->hdrlen + __entry->msglen) ); TRACE_EVENT(svcrdma_send_failed, diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index 85c91d0debb4..037be0bdb557 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -622,6 +622,45 @@ static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma, offset_in_page(base), len); } +struct svc_rdma_pullup_data { + u8 *pd_dest; + unsigned int pd_length; + unsigned int pd_num_sges; +}; + +/** + * svc_rdma_xb_count_sges - Count how many SGEs will be needed + * @xdr: xdr_buf containing portion of an RPC message to transmit + * @data: pointer to arguments + * + * Returns: + * Number of SGEs needed to Send the contents of @xdr inline + */ +static int svc_rdma_xb_count_sges(const struct xdr_buf *xdr, + void *data) +{ + struct svc_rdma_pullup_data *args = data; + unsigned int remaining; + unsigned long offset; + + if (xdr->head[0].iov_len) + ++args->pd_num_sges; + + offset = offset_in_page(xdr->page_base); + remaining = xdr->page_len; + while (remaining) { + ++args->pd_num_sges; + remaining -= min_t(u32, PAGE_SIZE - offset, remaining); + offset = 0; + } + + if (xdr->tail[0].iov_len) + ++args->pd_num_sges; + + args->pd_length += xdr->len; + return 0; +} + /** * svc_rdma_pull_up_needed - Determine whether to use pull-up * @rdma: controlling transport @@ -630,50 +669,70 @@ static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma, * @xdr: xdr_buf containing RPC message to transmit * * Returns: - * %true if pull-up must be used - * %false otherwise + * %true if pull-up must be used + * %false otherwise */ -static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma, - struct svc_rdma_send_ctxt *sctxt, +static bool svc_rdma_pull_up_needed(const struct svcxprt_rdma *rdma, + const struct svc_rdma_send_ctxt *sctxt, const struct svc_rdma_recv_ctxt *rctxt, - struct xdr_buf *xdr) + const struct xdr_buf *xdr) { - bool read_payload_present = rctxt && rctxt->rc_cur_payload; - int elements; + /* Resources needed for the transport header */ + struct svc_rdma_pullup_data args = { + .pd_length = sctxt->sc_hdrbuf.len, + .pd_num_sges = 1, + }; + int ret; - /* For small messages, copying bytes is cheaper than DMA mapping. - */ - if (!read_payload_present && - sctxt->sc_hdrbuf.len + xdr->len < RPCRDMA_PULLUP_THRESH) + ret = svc_rdma_skip_payloads(xdr, rctxt, svc_rdma_xb_count_sges, + &args); + if (ret < 0) + return false; + + if (args.pd_length < RPCRDMA_PULLUP_THRESH) return true; + return args.pd_num_sges >= rdma->sc_max_send_sges; +} - /* Check whether the xdr_buf has more elements than can - * fit in a single RDMA Send. - */ - /* xdr->head */ - elements = 1; - - /* xdr->pages */ - if (!read_payload_present) { - unsigned int remaining; - unsigned long pageoff; - - pageoff = xdr->page_base & ~PAGE_MASK; - remaining = xdr->page_len; - while (remaining) { - ++elements; - remaining -= min_t(u32, PAGE_SIZE - pageoff, - remaining); - pageoff = 0; - } +/** + * svc_rdma_xb_linearize - Copy region of xdr_buf to flat buffer + * @xdr: xdr_buf containing portion of an RPC message to copy + * @data: pointer to arguments + * + * Returns: + * Always zero. + */ +static int svc_rdma_xb_linearize(const struct xdr_buf *xdr, + void *data) +{ + struct svc_rdma_pullup_data *args = data; + unsigned int len, remaining; + unsigned long pageoff; + struct page **ppages; + + if (xdr->head[0].iov_len) { + memcpy(args->pd_dest, xdr->head[0].iov_base, xdr->head[0].iov_len); + args->pd_dest += xdr->head[0].iov_len; } - /* xdr->tail */ - if (xdr->tail[0].iov_len) - ++elements; + ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT); + pageoff = offset_in_page(xdr->page_base); + remaining = xdr->page_len; + while (remaining) { + len = min_t(u32, PAGE_SIZE - pageoff, remaining); + memcpy(args->pd_dest, page_address(*ppages), len); + remaining -= len; + args->pd_dest += len; + pageoff = 0; + } + + if (xdr->tail[0].iov_len) { + memcpy(args->pd_dest, xdr->tail[0].iov_base, xdr->tail[0].iov_len); + args->pd_dest += xdr->tail[0].iov_len; + } - /* assume 1 SGE is needed for the transport header */ - return elements >= rdma->sc_max_send_sges; + args->pd_length += xdr->len; + return 0; } /** @@ -686,53 +745,30 @@ static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma, * The device is not capable of sending the reply directly. * Assemble the elements of @xdr into the transport header buffer. * - * Returns zero on success, or a negative errno on failure. + * Assumptions: + * pull_up_needed has determined that @xdr will fit in the buffer. + * + * Returns: + * %0 if pull-up was successful + * %-EMSGSIZE if a buffer manipulation problem occurred */ -static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma, +static int svc_rdma_pull_up_reply_msg(const struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *sctxt, const struct svc_rdma_recv_ctxt *rctxt, const struct xdr_buf *xdr) { - unsigned char *dst, *tailbase; - unsigned int taillen; - - dst = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len; - memcpy(dst, xdr->head[0].iov_base, xdr->head[0].iov_len); - dst += xdr->head[0].iov_len; - - tailbase = xdr->tail[0].iov_base; - taillen = xdr->tail[0].iov_len; - if (rctxt && rctxt->rc_cur_payload) { - u32 xdrpad; - - xdrpad = xdr_pad_size(xdr->page_len); - if (taillen && xdrpad) { - tailbase += xdrpad; - taillen -= xdrpad; - } - } else { - unsigned int len, remaining; - unsigned long pageoff; - struct page **ppages; - - ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT); - pageoff = xdr->page_base & ~PAGE_MASK; - remaining = xdr->page_len; - while (remaining) { - len = min_t(u32, PAGE_SIZE - pageoff, remaining); - - memcpy(dst, page_address(*ppages), len); - remaining -= len; - dst += len; - pageoff = 0; - } - } + struct svc_rdma_pullup_data args = { + .pd_dest = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len, + }; + int ret; - if (taillen) - memcpy(dst, tailbase, taillen); + ret = svc_rdma_skip_payloads(xdr, rctxt, svc_rdma_xb_linearize, + &args); + if (ret < 0) + return ret; - sctxt->sc_sges[0].length += xdr->len; - trace_svcrdma_send_pullup(sctxt->sc_sges[0].length); + sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len + args.pd_length; + trace_svcrdma_send_pullup(sctxt->sc_hdrbuf.len, args.pd_length); return 0; }