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| author | Chuck Lever | 2015-01-21 17:03:02 +0100 |
|---|---|---|
| committer | Anna Schumaker | 2015-01-30 16:47:48 +0100 |
| commit | eba8ff660b2d8b7fcd6669fcab2c025b59f66d26 (patch) | |
| tree | 7a9a00e875d14cad14e389998a0f3cfbdfc94b83 /net/sunrpc/xprtrdma/rpc_rdma.c | |
| parent | xprtrdma: Remove rl_mr field, and the mr_chunk union (diff) | |
| download | kernel-qcow2-linux-eba8ff660b2d8b7fcd6669fcab2c025b59f66d26.tar.gz kernel-qcow2-linux-eba8ff660b2d8b7fcd6669fcab2c025b59f66d26.tar.xz kernel-qcow2-linux-eba8ff660b2d8b7fcd6669fcab2c025b59f66d26.zip | |
xprtrdma: Move credit update to RPC reply handler
Reduce work in the receive CQ handler, which can be run at hardware
interrupt level, by moving the RPC/RDMA credit update logic to the
RPC reply handler.
This has some additional benefits: More header sanity checking is
done before trusting the incoming credit value, and the receive CQ
handler no longer touches the RPC/RDMA header (the CPU stalls while
waiting for the header contents to be brought into the cache).
This further extends work begun by commit e7ce710a8802 ("xprtrdma:
Avoid deadlock when credit window is reset").
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/rpc_rdma.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/rpc_rdma.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index dcf5ebc3d373..d7310109b601 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -736,7 +736,7 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep) struct rpc_xprt *xprt = rep->rr_xprt; struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); __be32 *iptr; - int rdmalen, status; + int credits, rdmalen, status; unsigned long cwnd; /* Check status. If bad, signal disconnect and return rep to pool */ @@ -871,8 +871,14 @@ badheader: break; } + credits = be32_to_cpu(headerp->rm_credit); + if (credits == 0) + credits = 1; /* don't deadlock */ + else if (credits > r_xprt->rx_buf.rb_max_requests) + credits = r_xprt->rx_buf.rb_max_requests; + cwnd = xprt->cwnd; - xprt->cwnd = atomic_read(&r_xprt->rx_buf.rb_credits) << RPC_CWNDSHIFT; + xprt->cwnd = credits << RPC_CWNDSHIFT; if (xprt->cwnd > cwnd) xprt_release_rqst_cong(rqst->rq_task); |