net/mlx5e: Build SKB with exact frag_size

Build the SKB over the receive packet instead of the
whole page. Getting the SKB's linear data and shared_info
closer improves locality.
In addition, this opens up the possibility to make use of
other parts of the page in the downstream page-reuse patch.

Fixes: 1bfecfca565c ("net/mlx5e: Build RX SKB on demand")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 5d9ace4..6af1fbe 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -72,6 +72,8 @@
 #define MLX5E_PARAMS_MAXIMUM_LOG_RQ_SIZE_MPW            0x6
 
 #define MLX5_RX_HEADROOM NET_SKB_PAD
+#define MLX5_SKB_FRAG_SZ(len)  (SKB_DATA_ALIGN(len) +  \
+                                SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
 #define MLX5_MPWRQ_MIN_LOG_STRIDE_SZ(mdev) \
        (6 + MLX5_CAP_GEN(mdev, cache_line_128byte)) /* HW restriction */

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 167bca5..c991c1e 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -639,11 +639,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
                byte_count = rq->buff.wqe_sz;
 
                /* calc the required page order */
-               frag_sz = rq->rx_headroom +
-                         byte_count /* packet data */ +
-                         SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
-               frag_sz = SKB_DATA_ALIGN(frag_sz);
-
+               frag_sz = MLX5_SKB_FRAG_SZ(rq->rx_headroom + byte_count);
                npages = DIV_ROUND_UP(frag_sz, PAGE_SIZE);
                rq->buff.page_order = order_base_2(npages);
 

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index abf6d2f..2eef4e7 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -740,6 +740,7 @@ struct sk_buff *skb_from_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
        void *va, *data;
        u16 rx_headroom = rq->rx_headroom;
        bool consumed;
+       u32 frag_size;
 
        di             = &rq->dma_info[wqe_counter];
        va             = page_address(di->page);
@@ -764,7 +765,8 @@ struct sk_buff *skb_from_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
        if (consumed)
                return NULL; /* page/packet was consumed by XDP */
 
-       skb = build_skb(va, RQ_PAGE_SIZE(rq));
+       frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + cqe_bcnt);
+       skb = build_skb(va, frag_size);
        if (unlikely(!skb)) {
                rq->stats.buff_alloc_err++;
                mlx5e_page_release(rq, di, true);