Trond Myklebust wrote:
Hi Tom
On Tue, 2010-08-03 at 11:45 -0500, Tom Tucker wrote:
This patch updates the computation to include the worst case situation
where three FRMR are required to map a single RPC REQ.
Signed-off-by: Tom Tucker <tom@xxxxxx>
---
net/sunrpc/xprtrdma/rpc_rdma.c | 2 ++
net/sunrpc/xprtrdma/verbs.c | 20 ++++++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index e5e28d1..2ac3f6e 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -249,6 +249,8 @@ rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
req->rl_nchunks = nchunks;
BUG_ON(nchunks == 0);
+ BUG_ON((r_xprt->rx_ia.ri_memreg_strategy == RPCRDMA_FRMR)
+ && (nchunks > 3));
Where does the number 3 come from?
The assumption below is based on the premise that there is one chunk for
the header, one for the pagelist, and one for the tail == 3. I guess I
should have a comment -- sorry :-\
/*
* finish off header. If write, marshal discrim and nchunks.
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 3bdbd9f..5f4c7b3 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -650,10 +650,22 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
ep->rep_attr.cap.max_send_wr = cdata->max_requests;
switch (ia->ri_memreg_strategy) {
case RPCRDMA_FRMR:
- /* Add room for frmr register and invalidate WRs */
- ep->rep_attr.cap.max_send_wr *= 3;
- if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr)
- return -EINVAL;
+ /* Add room for frmr register and invalidate WRs.
+ * 1. FRMR reg WR for head
+ * 2. FRMR invalidate WR for head
+ * 3. FRMR reg WR for pagelist
+ * 4. FRMR invalidate WR for pagelist
+ * 5. FRMR reg WR for tail
+ * 6. FRMR invalidate WR for tail
+ * 7. The RDMA_SEND WR
+ */
+ ep->rep_attr.cap.max_send_wr *= 7;
+ if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr) {
+ cdata->max_requests = devattr.max_qp_wr / 7;
+ if (!cdata->max_requests)
+ return -EINVAL;
+ ep->rep_attr.cap.max_send_wr = cdata->max_requests * 7;
+ }
break;
case RPCRDMA_MEMWINDOWS_ASYNC:
case RPCRDMA_MEMWINDOWS:
--
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