[dpdk-dev] [PATCH v2 10/10] net/mlx5: reorganize rte flow structure

[Suanming Mou]

Currently, the rte flow structure is not fully aligned and has some
bits wasted. The members can be optimized and reorganized to save
memory.

1. The drv_type uses only limited bits, change the type to 2 bits what
it needs.

2. Align the hairpin_flow_id, drv_type, fdir, copy_applied to 32 bits.
As hairpin never uses the full 32 bits.

3. __rte_packed helps tight up the structure memory layout.

The optimization totally helps save 14 bytes for the structure.

Signed-off-by: Suanming Mou <suanmingm at mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
---
 drivers/net/mlx5/mlx5.c      |  3 ++-
 drivers/net/mlx5/mlx5_flow.h | 17 ++++++++++-------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
index 9ab4b1f..a83791c 100644
--- a/drivers/net/mlx5/mlx5.c
+++ b/drivers/net/mlx5/mlx5.c
@@ -764,7 +764,8 @@ struct mlx5_flow_id_pool *
 			goto error;
 		}
 	}
-	sh->flow_id_pool = mlx5_flow_id_pool_alloc(UINT32_MAX);
+	sh->flow_id_pool = mlx5_flow_id_pool_alloc
+					((1 << HAIRPIN_FLOW_ID_BITS) - 1);
 	if (!sh->flow_id_pool) {
 		DRV_LOG(ERR, "can't create flow id pool");
 		err = ENOMEM;
diff --git a/drivers/net/mlx5/mlx5_flow.h b/drivers/net/mlx5/mlx5_flow.h
index 35570a9..d697eba 100644
--- a/drivers/net/mlx5/mlx5_flow.h
+++ b/drivers/net/mlx5/mlx5_flow.h
@@ -760,20 +760,23 @@ struct mlx5_fdir_flow {
 	uint32_t rix_flow; /* Index to flow. */
 };
 
+#define HAIRPIN_FLOW_ID_BITS 28
+
 /* Flow structure. */
 struct rte_flow {
 	ILIST_ENTRY(uint32_t)next; /**< Index to the next flow structure. */
-	enum mlx5_flow_drv_type drv_type; /**< Driver type. */
-	uint32_t counter; /**< Holds flow counter. */
-	uint32_t rix_mreg_copy;
-	/**< Index to metadata register copy table resource. */
-	uint16_t meter; /**< Holds flow meter id. */
 	uint32_t dev_handles;
 	/**< Device flow handles that are part of the flow. */
+	uint32_t drv_type:2; /**< Driver type. */
 	uint32_t fdir:1; /**< Identifier of associated FDIR if any. */
-	uint32_t hairpin_flow_id; /**< The flow id used for hairpin. */
+	uint32_t hairpin_flow_id:HAIRPIN_FLOW_ID_BITS;
+	/**< The flow id used for hairpin. */
 	uint32_t copy_applied:1; /**< The MARK copy Flow os applied. */
-};
+	uint32_t rix_mreg_copy;
+	/**< Index to metadata register copy table resource. */
+	uint32_t counter; /**< Holds flow counter. */
+	uint16_t meter; /**< Holds flow meter id. */
+} __rte_packed;
 
 typedef int (*mlx5_flow_validate_t)(struct rte_eth_dev *dev,
 				    const struct rte_flow_attr *attr,
-- 
1.8.3.1