RDS: IB: Add vector spreading for cqs

Based on available device vectors, allocate cqs accordingly to
get better spread of completion vectors which helps performace
great deal..

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

1 files changed, 37 insertions, 3 deletions

diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 4d1bf04b06b5..33c8584ada1f 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -358,6 +358,28 @@ static void rds_ib_cq_comp_handler_send(struct ib_cq *cq, void *context)
         tasklet_schedule(&ic->i_send_tasklet);
 }
 
+static inline int ibdev_get_unused_vector(struct rds_ib_device *rds_ibdev)
+{
+        int min = rds_ibdev->vector_load[rds_ibdev->dev->num_comp_vectors - 1];
+        int index = rds_ibdev->dev->num_comp_vectors - 1;
+        int i;
+
+        for (i = rds_ibdev->dev->num_comp_vectors - 1; i >= 0; i--) {
+                if (rds_ibdev->vector_load[i] < min) {
+                        index = i;
+                        min = rds_ibdev->vector_load[i];
+                }
+        }
+
+        rds_ibdev->vector_load[index]++;
+        return index;
+}
+
+static inline void ibdev_put_vector(struct rds_ib_device *rds_ibdev, int index)
+{
+        rds_ibdev->vector_load[index]--;
+}
+
 /*
  * This needs to be very careful to not leave IS_ERR pointers around for
  * cleanup to trip over.
@@ -399,25 +421,30 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
         /* Protection domain and memory range */
         ic->i_pd = rds_ibdev->pd;
 
+        ic->i_scq_vector = ibdev_get_unused_vector(rds_ibdev);
         cq_attr.cqe = ic->i_send_ring.w_nr + fr_queue_space + 1;
-
+        cq_attr.comp_vector = ic->i_scq_vector;
         ic->i_send_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_send,
                                      rds_ib_cq_event_handler, conn,
                                      &cq_attr);
         if (IS_ERR(ic->i_send_cq)) {
                 ret = PTR_ERR(ic->i_send_cq);
                 ic->i_send_cq = NULL;
+                ibdev_put_vector(rds_ibdev, ic->i_scq_vector);
                 rdsdebug("ib_create_cq send failed: %d\n", ret);
                 goto out;
         }
 
+        ic->i_rcq_vector = ibdev_get_unused_vector(rds_ibdev);
         cq_attr.cqe = ic->i_recv_ring.w_nr;
+        cq_attr.comp_vector = ic->i_rcq_vector;
         ic->i_recv_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_recv,
                                      rds_ib_cq_event_handler, conn,
                                      &cq_attr);
         if (IS_ERR(ic->i_recv_cq)) {
                 ret = PTR_ERR(ic->i_recv_cq);
                 ic->i_recv_cq = NULL;
+                ibdev_put_vector(rds_ibdev, ic->i_rcq_vector);
                 rdsdebug("ib_create_cq recv failed: %d\n", ret);
                 goto out;
         }
@@ -780,10 +807,17 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp)
                 /* first destroy the ib state that generates callbacks */
                 if (ic->i_cm_id->qp)
                         rdma_destroy_qp(ic->i_cm_id);
-                if (ic->i_send_cq)
+                if (ic->i_send_cq) {
+                        if (ic->rds_ibdev)
+                                ibdev_put_vector(ic->rds_ibdev, ic->i_scq_vector);
                         ib_destroy_cq(ic->i_send_cq);
-                if (ic->i_recv_cq)
+                }
+
+                if (ic->i_recv_cq) {
+                        if (ic->rds_ibdev)
+                                ibdev_put_vector(ic->rds_ibdev, ic->i_rcq_vector);
                         ib_destroy_cq(ic->i_recv_cq);
+                }
 
                 /* then free the resources that ib callbacks use */
                 if (ic->i_send_hdrs)