On 3/29/2014 3:05 AM, Chuck Lever wrote:
On Mar 28, 2014, at 4:06 PM, sagi grimberg <sagig@xxxxxxxxxxxx> wrote:
On 3/29/2014 1:30 AM, Chuck Lever wrote:
On Mar 28, 2014, at 2:42 AM, Senn Klemens <klemens.senn@xxxxxxxxx> wrote:
Hi Chuck,
On 03/27/2014 04:59 PM, Chuck Lever wrote:
Hi-
On Mar 27, 2014, at 12:53 AM, Reiter Rafael <rafael.reiter@xxxxxxxxx> wrote:
On 03/26/2014 07:15 PM, Chuck Lever wrote:
Hi Rafael-
I’ll take a look. Can you report your HCA and how you reproduce this issue?
The HCA is Mellanox Technologies MT26428.
Reproduction:
1) Mount a directory via NFS/RDMA
mount -t nfs -o port=20049,rdma,vers=4.0,timeo=900 172.16.100.2:/ /mnt/
An additional "ls /mnt" is needed here (between step 1 and 2)
2) Pull the Infiniband cable or use ibportstate to disrupt the Infiniband connection
3) ls /mnt
4) wait 5-30 seconds
Thanks for the information.
I have that HCA, but I won’t have access to my test systems for a week (traveling). So can you try this:
# rpcdebug -m rpc -s trans
then reproduce (starting with step 1 above). Some debugging output will appear at the tail of /var/log/messages. Copy it to this thread.
The output of /var/log/messages is:
[ 143.233701] RPC: 1688 xprt_rdma_allocate: size 1112 too large for
buffer[1024]: prog 100003 vers 4 proc 1
[ 143.233708] RPC: 1688 xprt_rdma_allocate: size 1112, request
0xffff88105894c000
[ 143.233715] RPC: 1688 rpcrdma_inline_pullup: pad 0 destp
0xffff88105894d7dc len 124 hdrlen 124
[ 143.233718] RPC: rpcrdma_register_frmr_external: Using frmr
ffff88084e589260 to map 1 segments
[ 143.233722] RPC: 1688 rpcrdma_create_chunks: reply chunk elem
652@0x105894d92c:0xced01 (last)
[ 143.233725] RPC: 1688 rpcrdma_marshal_req: reply chunk: hdrlen 48
rpclen 124 padlen 0 headerp 0xffff88105894d100 base 0xffff88105894d760
lkey 0x8000
[ 143.233785] RPC: rpcrdma_event_process: event rep
ffff88084e589260 status 0 opcode 8 length 0
[ 177.272397] RPC: rpcrdma_event_process: event rep
(null) status C opcode FFFF8808 length 4294967295
[ 177.272649] RPC: rpcrdma_event_process: event rep
ffff880848ed0000 status 5 opcode FFFF8808 length 4294936584
The mlx4 provider is returning a WC completion status of
IB_WC_WR_FLUSH_ERR.
[ 177.272651] RPC: rpcrdma_event_process: WC opcode -30712 status
5, connection lost
-30712 is a bogus WC opcode. So the mlx4 provider is not filling in the
WC opcode. rpcrdma_event_process() thus can’t depend on the contents of
the ib_wc.opcode field when the WC completion status != IB_WC_SUCCESS.
Hey Chuck,
That is correct, the opcode field in the wc is not reliable in FLUSH errors.
A copy of the opcode reachable from the incoming rpcrdma_rep could be
added, initialized in the forward paths. rpcrdma_event_process() could
use the copy in the error case.
How about suppressing completions alltogether for fast_reg and local_inv work requests?
if these shall fail you will get an error completion and the QP will transition to error state
generating FLUSH_ERR completions for all pending WRs. In this case, you can just ignore
flush fast_reg + local_inv errors.
see http://marc.info/?l=linux-rdma&m=139047309831997&w=2
While considering your suggestion, I see that my proposed fix doesn’t work. In the FAST_REG_MR and LOCAL_INV cases, wr_id points to a struct rpcrdma_mw, not a struct rpcrdma_rep. Putting a copy of the opcode in rpcrdma_rep would have no effect. Worse:
158 if (IB_WC_SUCCESS != wc->status) {
159 dprintk("RPC: %s: WC opcode %d status %X, connection lost\n",
160 __func__, wc->opcode, wc->status);
161 rep->rr_len = ~0U;
Suppose this is an IB_WC_FAST_REG_MR completion, so “rep” here is actually a struct rpcrdma_mw, not a struct rpcrdma_rep. Line 161 pokes 32 one-bits at the top of that struct rpcrdma_mw. If wc->opcode was always usable, we’d at least have to fix that.
<nod>
So for error completions one needs to be careful dereferencing wr_id as
the opcode might not reliable. it will be better to first identify that
wr_id is indeed a pointer to rep.
162 if (wc->opcode != IB_WC_FAST_REG_MR && wc->opcode != IB_WC_LOCAL_INV)
163 rpcrdma_schedule_tasklet(rep);
164 return;
165 }
166
167 switch (wc->opcode) {
168 case IB_WC_FAST_REG_MR:
169 frmr = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
170 frmr->r.frmr.state = FRMR_IS_VALID;
171 break;
To make my initial solution work, you’d have to add a field to both struct rpcrdma_mw and struct rpcrdma_rep, and ensure they are at the same offset in both structures. Ewe.
Eliminating completions for FAST_REG_MR and LOCAL_INV might be a preferable way to address this.
Agree, Same applies for MW.
Sagi.
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