[PATCH v2 08/22] xprtrdma: Use smaller buffers for RPC-over-RDMA headers
From: Chuck Lever <hidden>
Date: 2016-08-23 17:53:09
Also in:
linux-nfs
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
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 <redacted>
---
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 --
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