Return-Path: Received: from mail-it0-f68.google.com ([209.85.214.68]:36057 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752444AbcHWSGA (ORCPT ); Tue, 23 Aug 2016 14:06:00 -0400 Subject: [PATCH v2 08/22] xprtrdma: Use smaller buffers for RPC-over-RDMA headers From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 23 Aug 2016 13:53:09 -0400 Message-ID: <20160823175309.13038.64696.stgit@manet.1015granger.net> In-Reply-To: <20160823174402.13038.84561.stgit@manet.1015granger.net> References: <20160823174402.13038.84561.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Commit 949317464bc2 ("xprtrdma: Limit number of RDMA segments in RPC-over-RDMA headers") capped the number of chunks that may appear in RPC-over-RDMA headers. The maximum header size can be estimated and fixed to avoid allocating buffer space that is never used. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/backchannel.c | 5 ++--- net/sunrpc/xprtrdma/transport.c | 2 +- net/sunrpc/xprtrdma/xprt_rdma.h | 5 ++++- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index c4904f8..60fc991 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -45,13 +45,12 @@ static int rpcrdma_bc_setup_rqst(struct rpcrdma_xprt *r_xprt, return PTR_ERR(req); req->rl_backchannel = true; - size = r_xprt->rx_data.inline_wsize; - rb = rpcrdma_alloc_regbuf(ia, size, GFP_KERNEL); + rb = rpcrdma_alloc_regbuf(ia, RPCRDMA_HDRBUF_SIZE, GFP_KERNEL); if (IS_ERR(rb)) goto out_fail; req->rl_rdmabuf = rb; - size += r_xprt->rx_data.inline_rsize; + size = r_xprt->rx_data.inline_rsize; rb = rpcrdma_alloc_regbuf(ia, size, GFP_KERNEL); if (IS_ERR(rb)) goto out_fail; diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index ecdc3ad..94dbfd3 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -484,7 +484,7 @@ static bool rpcrdma_get_rdmabuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, gfp_t flags) { - size_t size = r_xprt->rx_data.inline_wsize; + size_t size = RPCRDMA_HDRBUF_SIZE; struct rpcrdma_regbuf *rb; if (req->rl_rdmabuf) diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 73f915f..c5137f0 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -160,7 +160,10 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb) * The smallest inline threshold is 1024 bytes, ensuring that * at least 750 bytes are available for RPC messages. */ -#define RPCRDMA_MAX_HDR_SEGS (8) +enum { + RPCRDMA_MAX_HDR_SEGS = 8, + RPCRDMA_HDRBUF_SIZE = 256, +}; /* * struct rpcrdma_rep -- this structure encapsulates state required to recv