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| author | Chuck Lever <chuck.lever@oracle.com> | 2020-12-22 21:22:20 +0300 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2021-03-31 22:57:39 +0300 |
| commit | 7d81ee8722d69f753c88e7d594790fa10a384f1a (patch) | |
| tree | be43bbe533a2c8f3a333286256199bd1df536b06 /net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | |
| parent | 82011c80b3ec0e05940a2ee2c76c1df9fd2b1ce8 (diff) | |
| download | linux-7d81ee8722d69f753c88e7d594790fa10a384f1a.tar.xz | |
svcrdma: Single-stage RDMA Read
Currently the generic RPC server layer calls svc_rdma_recvfrom()
twice to retrieve an RPC message that uses Read chunks. I'm not
exactly sure why this design was chosen originally.
Instead, let's wait for the Read chunk completion inline in the
first call to svc_rdma_recvfrom().
The goal is to eliminate some page allocator churn.
rdma_read_complete() replaces pages in the second svc_rqst by
calling put_page() repeatedly while the upper layer waits for the
request to be constructed, which adds unnecessary NFS WRITE round-
trip latency.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Tom Talpey <tom@talpey.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 9cb5a09c4a01..ae932435e1d3 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -853,6 +853,9 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) spin_unlock(&rdma_xprt->sc_rq_dto_lock); percpu_counter_inc(&svcrdma_stat_recv); + /* Unblock the transport for the next receive */ + svc_xprt_received(xprt); + ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device, ctxt->rc_recv_sge.addr, ctxt->rc_byte_len, DMA_FROM_DEVICE); @@ -884,33 +887,28 @@ complete: rqstp->rq_xprt_ctxt = ctxt; rqstp->rq_prot = IPPROTO_MAX; svc_xprt_copy_addrs(rqstp, xprt); - svc_xprt_received(xprt); return rqstp->rq_arg.len; out_readlist: ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt); if (ret < 0) goto out_readfail; - svc_xprt_received(xprt); - return 0; + goto complete; out_err: svc_rdma_send_error(rdma_xprt, ctxt, ret); svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); - svc_xprt_received(xprt); return 0; out_readfail: if (ret == -EINVAL) svc_rdma_send_error(rdma_xprt, ctxt, ret); svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); - svc_xprt_received(xprt); return ret; out_backchannel: svc_rdma_handle_bc_reply(rqstp, ctxt); out_drop: svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); - svc_xprt_received(xprt); return 0; } |