[PATCH V3 12/17] xprtrmda: Reduce lock contention in completion handlers

[Chuck Lever]

Skip the ib_poll_cq() after re-arming, if the provider knows there
are no additional items waiting. (Have a look at commit ed23a727 for
more details).

Signed-off-by: Chuck Lever <chuck.le...@oracle.com>
---

 net/sunrpc/xprtrdma/verbs.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index af2d097..c7d5281 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -192,8 +192,11 @@ rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context)
                return;
        }
 
-       rc = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
-       if (rc) {
+       rc = ib_req_notify_cq(cq,
+                       IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
+       if (rc == 0)
+               return;
+       if (rc < 0) {
                dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
                        __func__, rc);
                return;
@@ -272,8 +275,11 @@ rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context)
                return;
        }
 
-       rc = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
-       if (rc) {
+       rc = ib_req_notify_cq(cq,
+                       IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
+       if (rc == 0)
+               return;
+       if (rc < 0) {
                dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
                        __func__, rc);
                return;

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