> On Nov 20, 2018, at 1:02 PM, Anna Schumaker <schumaker.anna@xxxxxxxxx> wrote:
>
> Hi Chuck,
>
> On Mon, 2018-11-19 at 10:46 -0500, Chuck Lever wrote:
>> Place the associated RPC transaction's XID in the upper 32 bits of
>> each RDMA segment's rdma_offset field. These bits are currently
>> always zero.
>>
>> There are two reasons to do this:
>>
>> - The R_key only has 8 bits that are different from registration to
>> registration. The XID adds more uniqueness to each RDMA segment to
>> reduce the likelihood of a software bug on the server reading from
>> or writing into memory it's not supposed to.
>>
>> - On-the-wire RDMA Read and Write operations do not otherwise carry
>> any identifier that matches them up to an RPC. The XID in the
>> upper 32 bits will act as an eye-catcher in network captures.
>>
>> Suggested-by: Tom Talpey <ttalpey@xxxxxxxxxxxxx>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> net/sunrpc/xprtrdma/frwr_ops.c | 3 ++-
>> net/sunrpc/xprtrdma/rpc_rdma.c | 6 +++---
>> net/sunrpc/xprtrdma/xprt_rdma.h | 2 +-
>> 3 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
>> index 49b314d..3b260d2 100644
>> --- a/net/sunrpc/xprtrdma/frwr_ops.c
>> +++ b/net/sunrpc/xprtrdma/frwr_ops.c
>> @@ -344,7 +344,7 @@
>> */
>> static struct rpcrdma_mr_seg *
>> frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
>> - int nsegs, bool writing, struct rpcrdma_mr **out)
>> + int nsegs, bool writing, u32 xid, struct rpcrdma_mr **out)
>> {
>> struct rpcrdma_ia *ia = &r_xprt->rx_ia;
>> bool holes_ok = ia->ri_mrtype == IB_MR_TYPE_SG_GAPS;
>> @@ -398,6 +398,7 @@
>> if (unlikely(n != mr->mr_nents))
>> goto out_mapmr_err;
>>
>> + ibmr->iova |= ((u64)cpu_to_be32(xid)) << 32;
>
> My mount command hangs once we make this change (I got bored and killed it after
> about 5 minutes). This is with NFS over soft-RoCE in a kvm virtual machine, and
> I see the behavior with all NFS versions.
>
> I hope this helps!
OK. Can you capture ftrace output to show us where the hang occurs?
I use this on the NFS client:
# trace-cmd record -e sunrpc -e rpcrdma
^C
# trace-cmd report | less (or > /tmp/trace.log)
Thanks!
> Anna
>
>> key = (u8)(ibmr->rkey & 0x000000FF);
>> ib_update_fast_reg_key(ibmr, ++key);
>>
>> diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
>> index 9f53e02..89a2db2 100644
>> --- a/net/sunrpc/xprtrdma/rpc_rdma.c
>> +++ b/net/sunrpc/xprtrdma/rpc_rdma.c
>> @@ -357,7 +357,7 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt
>> *r_xprt,
>>
>> do {
>> seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
>> - false, &mr);
>> + false, rqst->rq_xid, &mr);
>> if (IS_ERR(seg))
>> return PTR_ERR(seg);
>> rpcrdma_mr_push(mr, &req->rl_registered);
>> @@ -415,7 +415,7 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt
>> *r_xprt,
>> nchunks = 0;
>> do {
>> seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
>> - true, &mr);
>> + true, rqst->rq_xid, &mr);
>> if (IS_ERR(seg))
>> return PTR_ERR(seg);
>> rpcrdma_mr_push(mr, &req->rl_registered);
>> @@ -473,7 +473,7 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt
>> *r_xprt,
>> nchunks = 0;
>> do {
>> seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
>> - true, &mr);
>> + true, rqst->rq_xid, &mr);
>> if (IS_ERR(seg))
>> return PTR_ERR(seg);
>> rpcrdma_mr_push(mr, &req->rl_registered);
>> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
>> index a13ccb6..2ae1ee2 100644
>> --- a/net/sunrpc/xprtrdma/xprt_rdma.h
>> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h
>> @@ -472,7 +472,7 @@ struct rpcrdma_memreg_ops {
>> struct rpcrdma_mr_seg *
>> (*ro_map)(struct rpcrdma_xprt *,
>> struct rpcrdma_mr_seg *, int, bool,
>> - struct rpcrdma_mr **);
>> + u32, struct rpcrdma_mr **);
>> int (*ro_send)(struct rpcrdma_ia *ia,
>> struct rpcrdma_req *req);
>> void (*ro_reminv)(struct rpcrdma_rep *rep,
--
Chuck Lever
