From dbcc53a52df256880c2ffa4ee45661419435998a Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 24 Apr 2019 09:39:53 -0400 Subject: [PATCH] xprtrdma: Clean up sendctx functions Minor clean-ups I've stumbled on since sendctx was merged last year. In particular, making Send completion processing more efficient appears to have a measurable impact on IOPS throughput. Note: test_and_clear_bit() returns a value, thus an explicit memory barrier is not necessary. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/rpc_rdma.c | 27 ++++++++++++--------------- net/sunrpc/xprtrdma/verbs.c | 17 ++++++++--------- net/sunrpc/xprtrdma/xprt_rdma.h | 5 +++-- 3 files changed, 23 insertions(+), 26 deletions(-) diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 45cba06..5cb060c 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -508,30 +508,26 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, } /** - * rpcrdma_unmap_sendctx - DMA-unmap Send buffers + * rpcrdma_sendctx_unmap - DMA-unmap Send buffer * @sc: sendctx containing SGEs to unmap * */ -void -rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc) +void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc) { - struct rpcrdma_ia *ia = &sc->sc_xprt->rx_ia; struct ib_sge *sge; - unsigned int count; /* The first two SGEs contain the transport header and * the inline buffer. These are always left mapped so * they can be cheaply re-used. */ - sge = &sc->sc_sges[2]; - for (count = sc->sc_unmap_count; count; ++sge, --count) - ib_dma_unmap_page(ia->ri_device, - sge->addr, sge->length, DMA_TO_DEVICE); + for (sge = &sc->sc_sges[2]; sc->sc_unmap_count; + ++sge, --sc->sc_unmap_count) + ib_dma_unmap_page(sc->sc_device, sge->addr, sge->length, + DMA_TO_DEVICE); - if (test_and_clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &sc->sc_req->rl_flags)) { - smp_mb__after_atomic(); + if (test_and_clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, + &sc->sc_req->rl_flags)) wake_up_bit(&sc->sc_req->rl_flags, RPCRDMA_REQ_F_TX_RESOURCES); - } } /* Prepare an SGE for the RPC-over-RDMA transport header. @@ -578,6 +574,7 @@ static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt, */ if (!rpcrdma_regbuf_dma_map(r_xprt, rb)) goto out_regbuf; + sc->sc_device = rdmab_device(rb); sge_no = 1; sge[sge_no].addr = rdmab_addr(rb); sge[sge_no].length = xdr->head[0].iov_len; @@ -673,12 +670,12 @@ out_regbuf: return false; out_mapping_overflow: - rpcrdma_unmap_sendctx(sc); + rpcrdma_sendctx_unmap(sc); pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no); return false; out_mapping_err: - rpcrdma_unmap_sendctx(sc); + rpcrdma_sendctx_unmap(sc); trace_xprtrdma_dma_maperr(sge[sge_no].addr); return false; } @@ -698,7 +695,7 @@ rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, u32 hdrlen, struct xdr_buf *xdr, enum rpcrdma_chunktype rtype) { - req->rl_sendctx = rpcrdma_sendctx_get_locked(&r_xprt->rx_buf); + req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt); if (!req->rl_sendctx) return -EAGAIN; req->rl_sendctx->sc_wr.num_sge = 0; diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 81548fc2..1ad2519 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -870,20 +870,20 @@ static unsigned long rpcrdma_sendctx_next(struct rpcrdma_buffer *buf, /** * rpcrdma_sendctx_get_locked - Acquire a send context - * @buf: transport buffers from which to acquire an unused context + * @r_xprt: controlling transport instance * * Returns pointer to a free send completion context; or NULL if * the queue is empty. * * Usage: Called to acquire an SGE array before preparing a Send WR. * - * The caller serializes calls to this function (per rpcrdma_buffer), - * and provides an effective memory barrier that flushes the new value + * The caller serializes calls to this function (per transport), and + * provides an effective memory barrier that flushes the new value * of rb_sc_head. */ -struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf) +struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt) { - struct rpcrdma_xprt *r_xprt; + struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_sendctx *sc; unsigned long next_head; @@ -908,7 +908,6 @@ out_emptyq: * backing up. Cause the caller to pause and try again. */ set_bit(RPCRDMA_BUF_F_EMPTY_SCQ, &buf->rb_flags); - r_xprt = container_of(buf, struct rpcrdma_xprt, rx_buf); r_xprt->rx_stats.empty_sendctx_q++; return NULL; } @@ -920,7 +919,7 @@ out_emptyq: * Usage: Called from Send completion to return a sendctxt * to the queue. * - * The caller serializes calls to this function (per rpcrdma_buffer). + * The caller serializes calls to this function (per transport). */ static void rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc) @@ -928,7 +927,7 @@ rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc) struct rpcrdma_buffer *buf = &sc->sc_xprt->rx_buf; unsigned long next_tail; - /* Unmap SGEs of previously completed by unsignaled + /* Unmap SGEs of previously completed but unsignaled * Sends by walking up the queue until @sc is found. */ next_tail = buf->rb_sc_tail; @@ -936,7 +935,7 @@ rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc) next_tail = rpcrdma_sendctx_next(buf, next_tail); /* ORDER: item must be accessed _before_ tail is updated */ - rpcrdma_unmap_sendctx(buf->rb_sc_ctxs[next_tail]); + rpcrdma_sendctx_unmap(buf->rb_sc_ctxs[next_tail]); } while (buf->rb_sc_ctxs[next_tail] != sc); diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 7621e2d..8afb5fc 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -225,6 +225,7 @@ struct rpcrdma_xprt; struct rpcrdma_sendctx { struct ib_send_wr sc_wr; struct ib_cqe sc_cqe; + struct ib_device *sc_device; struct rpcrdma_xprt *sc_xprt; struct rpcrdma_req *sc_req; unsigned int sc_unmap_count; @@ -536,7 +537,7 @@ struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, void rpcrdma_req_destroy(struct rpcrdma_req *req); int rpcrdma_buffer_create(struct rpcrdma_xprt *); void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); -struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf); +struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); void rpcrdma_mr_put(struct rpcrdma_mr *mr); @@ -625,7 +626,7 @@ int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, u32 hdrlen, struct xdr_buf *xdr, enum rpcrdma_chunktype rtype); -void rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc); +void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc); int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst); void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *); void rpcrdma_complete_rqst(struct rpcrdma_rep *rep); -- 2.7.4