[dpdk-dev] [PATCH v2 9/9] net/mlx5: use an RSS drop queue

[Nelio Laranjeiro]

Having a drop queue per drop flow consumes a lot of memory and reduce the
speed capabilities of the NIC to handle such cases.
To avoid this and reduce memory consumption, an RSS drop queue is created
for all drop flows.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
---
 drivers/net/mlx5/mlx5.h      |   1 +
 drivers/net/mlx5/mlx5_flow.c | 218 +++++++++++++++++++++++++++++--------------
 2 files changed, 147 insertions(+), 72 deletions(-)

diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index 7ba2886..870e01f 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -152,6 +152,7 @@ struct priv {
 	unsigned int reta_idx_n; /* RETA index size. */
 	struct fdir_filter_list *fdir_filter_list; /* Flow director rules. */
 	struct fdir_queue *fdir_drop_queue; /* Flow director drop queue. */
+	struct rte_flow_drop *flow_drop_queue; /* Flow drop queue. */
 	LIST_HEAD(mlx5_flows, rte_flow) flows; /* RTE Flow rules. */
 	uint32_t link_speed_capa; /* Link speed capabilities. */
 	struct mlx5_xstats_ctrl xstats_ctrl; /* Extended stats control. */
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 99d0377..e789c4c 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -52,6 +52,9 @@
 #include "mlx5.h"
 #include "mlx5_prm.h"
 
+/* Number of Work Queue necessary for the DROP queue. */
+#define MLX5_DROP_WQ_N 4
+
 static int
 mlx5_flow_create_eth(const struct rte_flow_item *item,
 		     const void *default_mask,
@@ -279,6 +282,14 @@ struct mlx5_flow {
 	uint64_t hash_fields; /**< Fields that participate in the hash. */
 };
 
+/** Structure for Drop queue. */
+struct rte_flow_drop {
+	struct ibv_exp_rwq_ind_table *ind_table; /**< Indirection table. */
+	struct ibv_qp *qp; /**< Verbs queue pair. */
+	struct ibv_exp_wq *wqs[MLX5_DROP_WQ_N]; /**< Verbs work queue. */
+	struct ibv_cq *cq; /**< Verbs completion queue. */
+};
+
 struct mlx5_flow_action {
 	uint32_t queue:1; /**< Target is a receive queue. */
 	uint32_t drop:1; /**< Target is a drop queue. */
@@ -948,70 +959,9 @@ priv_flow_create_action_queue_drop(struct priv *priv,
 				   NULL, "cannot allocate flow memory");
 		return NULL;
 	}
-	rte_flow->cq =
-		ibv_exp_create_cq(priv->ctx, 1, NULL, NULL, 0,
-				  &(struct ibv_exp_cq_init_attr){
-					  .comp_mask = 0,
-				  });
-	if (!rte_flow->cq) {
-		rte_flow_error_set(error, ENOMEM,
-				   RTE_FLOW_ERROR_TYPE_HANDLE,
-				   NULL, "cannot allocate CQ");
-		goto error;
-	}
-	rte_flow->wq = ibv_exp_create_wq(priv->ctx,
-					 &(struct ibv_exp_wq_init_attr){
-					 .wq_type = IBV_EXP_WQT_RQ,
-					 .max_recv_wr = 1,
-					 .max_recv_sge = 1,
-					 .pd = priv->pd,
-					 .cq = rte_flow->cq,
-					 });
-	if (!rte_flow->wq) {
-		rte_flow_error_set(error, ENOMEM,
-				   RTE_FLOW_ERROR_TYPE_HANDLE,
-				   NULL, "cannot allocate WQ");
-		goto error;
-	}
 	rte_flow->drop = 1;
 	rte_flow->ibv_attr = flow->ibv_attr;
-	rte_flow->ind_table = ibv_exp_create_rwq_ind_table(
-		priv->ctx,
-		&(struct ibv_exp_rwq_ind_table_init_attr){
-			.pd = priv->pd,
-			.log_ind_tbl_size = 0,
-			.ind_tbl = &rte_flow->wq,
-			.comp_mask = 0,
-		});
-	if (!rte_flow->ind_table) {
-		rte_flow_error_set(error, ENOMEM, RTE_FLOW_ERROR_TYPE_HANDLE,
-				   NULL, "cannot allocate indirection table");
-		goto error;
-	}
-	rte_flow->qp = ibv_exp_create_qp(
-		priv->ctx,
-		&(struct ibv_exp_qp_init_attr){
-			.qp_type = IBV_QPT_RAW_PACKET,
-			.comp_mask =
-				IBV_EXP_QP_INIT_ATTR_PD |
-				IBV_EXP_QP_INIT_ATTR_PORT |
-				IBV_EXP_QP_INIT_ATTR_RX_HASH,
-			.pd = priv->pd,
-			.rx_hash_conf = &(struct ibv_exp_rx_hash_conf){
-				.rx_hash_function =
-					IBV_EXP_RX_HASH_FUNC_TOEPLITZ,
-				.rx_hash_key_len = rss_hash_default_key_len,
-				.rx_hash_key = rss_hash_default_key,
-				.rx_hash_fields_mask = 0,
-				.rwq_ind_tbl = rte_flow->ind_table,
-			},
-			.port_num = priv->port,
-		});
-	if (!rte_flow->qp) {
-		rte_flow_error_set(error, ENOMEM, RTE_FLOW_ERROR_TYPE_HANDLE,
-				   NULL, "cannot allocate QP");
-		goto error;
-	}
+	rte_flow->qp = priv->flow_drop_queue->qp;
 	if (!priv->started)
 		return rte_flow;
 	rte_flow->ibv_flow = ibv_exp_create_flow(rte_flow->qp,
@@ -1024,14 +974,6 @@ priv_flow_create_action_queue_drop(struct priv *priv,
 	return rte_flow;
 error:
 	assert(rte_flow);
-	if (rte_flow->qp)
-		ibv_destroy_qp(rte_flow->qp);
-	if (rte_flow->ind_table)
-		ibv_exp_destroy_rwq_ind_table(rte_flow->ind_table);
-	if (rte_flow->wq)
-		ibv_exp_destroy_wq(rte_flow->wq);
-	if (rte_flow->cq)
-		ibv_destroy_cq(rte_flow->cq);
 	rte_free(rte_flow);
 	return NULL;
 }
@@ -1309,6 +1251,8 @@ priv_flow_destroy(struct priv *priv,
 	LIST_REMOVE(flow, next);
 	if (flow->ibv_flow)
 		claim_zero(ibv_exp_destroy_flow(flow->ibv_flow));
+	if (flow->drop)
+		goto free;
 	if (flow->qp)
 		claim_zero(ibv_destroy_qp(flow->qp));
 	if (flow->ind_table)
@@ -1349,6 +1293,7 @@ priv_flow_destroy(struct priv *priv,
 			rxq->mark = !!mark_n;
 		}
 	}
+free:
 	rte_free(flow->ibv_attr);
 	DEBUG("Flow destroyed %p", (void *)flow);
 	rte_free(flow);
@@ -1411,6 +1356,125 @@ mlx5_flow_flush(struct rte_eth_dev *dev,
 }
 
 /**
+ * Create drop queue.
+ *
+ * @param priv
+ *   Pointer to private structure.
+ *
+ * @return
+ *   0 on success.
+ */
+static int
+priv_flow_create_drop_queue(struct priv *priv)
+{
+	struct rte_flow_drop *fdq = NULL;
+	unsigned int i;
+
+	assert(priv->pd);
+	assert(priv->ctx);
+	fdq = rte_calloc(__func__, 1, sizeof(*fdq), 0);
+	if (!fdq) {
+		WARN("cannot allocate memory for drop queue");
+		goto error;
+	}
+	fdq->cq = ibv_exp_create_cq(priv->ctx, 1, NULL, NULL, 0,
+			&(struct ibv_exp_cq_init_attr){
+			.comp_mask = 0,
+			});
+	if (!fdq->cq) {
+		WARN("cannot allocate CQ for drop queue");
+		goto error;
+	}
+	for (i = 0; i != MLX5_DROP_WQ_N; ++i) {
+		fdq->wqs[i] = ibv_exp_create_wq(priv->ctx,
+				&(struct ibv_exp_wq_init_attr){
+				.wq_type = IBV_EXP_WQT_RQ,
+				.max_recv_wr = 1,
+				.max_recv_sge = 1,
+				.pd = priv->pd,
+				.cq = fdq->cq,
+				});
+		if (!fdq->wqs[i]) {
+			WARN("cannot allocate WQ for drop queue");
+			goto error;
+		}
+	}
+	fdq->ind_table = ibv_exp_create_rwq_ind_table(priv->ctx,
+			&(struct ibv_exp_rwq_ind_table_init_attr){
+			.pd = priv->pd,
+			.log_ind_tbl_size = 0,
+			.ind_tbl = fdq->wqs,
+			.comp_mask = 0,
+			});
+	if (!fdq->ind_table) {
+		WARN("cannot allocate indirection table for drop queue");
+		goto error;
+	}
+	fdq->qp = ibv_exp_create_qp(priv->ctx,
+		&(struct ibv_exp_qp_init_attr){
+			.qp_type = IBV_QPT_RAW_PACKET,
+			.comp_mask =
+				IBV_EXP_QP_INIT_ATTR_PD |
+				IBV_EXP_QP_INIT_ATTR_PORT |
+				IBV_EXP_QP_INIT_ATTR_RX_HASH,
+			.pd = priv->pd,
+			.rx_hash_conf = &(struct ibv_exp_rx_hash_conf){
+				.rx_hash_function =
+					IBV_EXP_RX_HASH_FUNC_TOEPLITZ,
+				.rx_hash_key_len = rss_hash_default_key_len,
+				.rx_hash_key = rss_hash_default_key,
+				.rx_hash_fields_mask = 0,
+				.rwq_ind_tbl = fdq->ind_table,
+				},
+			.port_num = priv->port,
+			});
+	if (!fdq->qp) {
+		WARN("cannot allocate QP for drop queue");
+		goto error;
+	}
+	priv->flow_drop_queue = fdq;
+	return 0;
+error:
+	if (fdq->qp)
+		claim_zero(ibv_destroy_qp(fdq->qp));
+	if (fdq->ind_table)
+		claim_zero(ibv_exp_destroy_rwq_ind_table(fdq->ind_table));
+	for (i = 0; i != MLX5_DROP_WQ_N; ++i) {
+		if (fdq->wqs[i])
+			claim_zero(ibv_exp_destroy_wq(fdq->wqs[i]));
+	}
+	if (fdq->cq)
+		claim_zero(ibv_destroy_cq(fdq->cq));
+	if (fdq)
+		rte_free(fdq);
+	priv->flow_drop_queue = NULL;
+	return -1;
+}
+
+/**
+ * Delete drop queue.
+ *
+ * @param priv
+ *   Pointer to private structure.
+ */
+static void
+priv_flow_delete_drop_queue(struct priv *priv)
+{
+	struct rte_flow_drop *fdq = priv->flow_drop_queue;
+	unsigned int i;
+
+	claim_zero(ibv_destroy_qp(fdq->qp));
+	claim_zero(ibv_exp_destroy_rwq_ind_table(fdq->ind_table));
+	for (i = 0; i != MLX5_DROP_WQ_N; ++i) {
+		assert(fdq->wqs[i]);
+		claim_zero(ibv_exp_destroy_wq(fdq->wqs[i]));
+	}
+	claim_zero(ibv_destroy_cq(fdq->cq));
+	rte_free(fdq);
+	priv->flow_drop_queue = NULL;
+}
+
+/**
  * Remove all flows.
  *
  * Called by dev_stop() to remove all flows.
@@ -1436,6 +1500,7 @@ priv_flow_stop(struct priv *priv)
 		}
 		DEBUG("Flow %p removed", (void *)flow);
 	}
+	priv_flow_delete_drop_queue(priv);
 }
 
 /**
@@ -1450,13 +1515,22 @@ priv_flow_stop(struct priv *priv)
 int
 priv_flow_start(struct priv *priv)
 {
+	int ret;
 	struct rte_flow *flow;
 
+	ret = priv_flow_create_drop_queue(priv);
+	if (ret)
+		return -1;
 	for (flow = LIST_FIRST(&priv->flows);
 	     flow;
 	     flow = LIST_NEXT(flow, next)) {
-		flow->ibv_flow = ibv_exp_create_flow(flow->qp,
-						     flow->ibv_attr);
+		struct ibv_qp *qp;
+
+		if (flow->drop)
+			qp = priv->flow_drop_queue->qp;
+		else
+			qp = flow->qp;
+		flow->ibv_flow = ibv_exp_create_flow(qp, flow->ibv_attr);
 		if (!flow->ibv_flow) {
 			DEBUG("Flow %p cannot be applied", (void *)flow);
 			rte_errno = EINVAL;
-- 
2.1.4