From bb93a1ae2bf4f6eb3cedf05a2ea4a2e6a80712e6 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 24 Apr 2019 09:39:21 -0400 Subject: [PATCH] xprtrdma: Allocate req's regbufs at xprt create time Allocating an rpcrdma_req's regbufs at xprt create time enables a pair of micro-optimizations: First, if these regbufs are always there, we can eliminate two conditional branches from the hot xprt_rdma_allocate path. Second, by allocating a 1KB buffer, it places a lower bound on the size of these buffers, without adding yet another conditional branch. The lower bound reduces the number of hardway re- allocations. In fact, for some workloads it completely eliminates hardway allocations. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/backchannel.c | 18 ++++------------ net/sunrpc/xprtrdma/transport.c | 4 ++-- net/sunrpc/xprtrdma/verbs.c | 34 +++++++++++++++++++++++-------- net/sunrpc/xprtrdma/xprt_rdma.h | 2 +- 4 files changed, 33 insertions(+), 25 deletions(-) diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index 6170ec7ba504..e1a125ad888d 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -28,10 +28,10 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt, unsigned int i; for (i = 0; i < (count << 1); i++) { - struct rpcrdma_regbuf *rb; size_t size; - req = rpcrdma_req_create(r_xprt, GFP_KERNEL); + size = min_t(size_t, r_xprt->rx_data.inline_rsize, PAGE_SIZE); + req = rpcrdma_req_create(r_xprt, size, GFP_KERNEL); if (!req) return -ENOMEM; rqst = &req->rl_slot; @@ -42,20 +42,10 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt, spin_lock(&xprt->bc_pa_lock); list_add(&rqst->rq_bc_pa_list, &xprt->bc_pa_list); spin_unlock(&xprt->bc_pa_lock); - - size = r_xprt->rx_data.inline_rsize; - rb = rpcrdma_alloc_regbuf(size, DMA_TO_DEVICE, GFP_KERNEL); - if (!rb) - goto out_fail; - req->rl_sendbuf = rb; - xdr_buf_init(&rqst->rq_snd_buf, rdmab_data(rb), - min_t(size_t, size, PAGE_SIZE)); + xdr_buf_init(&rqst->rq_snd_buf, rdmab_data(req->rl_sendbuf), + size); } return 0; - -out_fail: - rpcrdma_req_destroy(req); - return -ENOMEM; } /** diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index ced9812940f7..a5da43f3b035 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -591,7 +591,7 @@ rpcrdma_get_sendbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, { struct rpcrdma_regbuf *rb; - if (req->rl_sendbuf && rdmab_length(req->rl_sendbuf) >= size) + if (likely(rdmab_length(req->rl_sendbuf) >= size)) return true; rb = rpcrdma_alloc_regbuf(size, DMA_TO_DEVICE, flags); @@ -621,7 +621,7 @@ rpcrdma_get_recvbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, { struct rpcrdma_regbuf *rb; - if (req->rl_recvbuf && rdmab_length(req->rl_recvbuf) >= size) + if (likely(rdmab_length(req->rl_recvbuf) >= size)) return true; rb = rpcrdma_alloc_regbuf(size, DMA_NONE, flags); diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index f88fd3934f56..77e0f21c9017 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -998,11 +998,13 @@ rpcrdma_mr_refresh_worker(struct work_struct *work) /** * rpcrdma_req_create - Allocate an rpcrdma_req object * @r_xprt: controlling r_xprt + * @size: initial size, in bytes, of send and receive buffers * @flags: GFP flags passed to memory allocators * * Returns an allocated and fully initialized rpcrdma_req or NULL. */ -struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, gfp_t flags) +struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, + gfp_t flags) { struct rpcrdma_buffer *buffer = &r_xprt->rx_buf; struct rpcrdma_regbuf *rb; @@ -1010,22 +1012,37 @@ struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, gfp_t flags) req = kzalloc(sizeof(*req), flags); if (req == NULL) - return NULL; + goto out1; rb = rpcrdma_alloc_regbuf(RPCRDMA_HDRBUF_SIZE, DMA_TO_DEVICE, flags); - if (!rb) { - kfree(req); - return NULL; - } + if (!rb) + goto out2; req->rl_rdmabuf = rb; xdr_buf_init(&req->rl_hdrbuf, rdmab_data(rb), rdmab_length(rb)); + + req->rl_sendbuf = rpcrdma_alloc_regbuf(size, DMA_TO_DEVICE, flags); + if (!req->rl_sendbuf) + goto out3; + + req->rl_recvbuf = rpcrdma_alloc_regbuf(size, DMA_NONE, flags); + if (!req->rl_recvbuf) + goto out4; + req->rl_buffer = buffer; INIT_LIST_HEAD(&req->rl_registered); - spin_lock(&buffer->rb_lock); list_add(&req->rl_all, &buffer->rb_allreqs); spin_unlock(&buffer->rb_lock); return req; + +out4: + kfree(req->rl_sendbuf); +out3: + kfree(req->rl_rdmabuf); +out2: + kfree(req); +out1: + return NULL; } static bool rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt, bool temp) @@ -1090,7 +1107,8 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) for (i = 0; i < buf->rb_max_requests; i++) { struct rpcrdma_req *req; - req = rpcrdma_req_create(r_xprt, GFP_KERNEL); + req = rpcrdma_req_create(r_xprt, RPCRDMA_V1_DEF_INLINE_SIZE, + GFP_KERNEL); if (!req) goto out; list_add(&req->rl_list, &buf->rb_send_bufs); diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 1af9674572bd..03d5ce443bf0 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -529,7 +529,7 @@ int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *, /* * Buffer calls - xprtrdma/verbs.c */ -struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, +struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, gfp_t flags); void rpcrdma_req_destroy(struct rpcrdma_req *req); int rpcrdma_buffer_create(struct rpcrdma_xprt *); -- 2.30.2