Re: [PATCH RFC v2 16/33] mlx4: add XDP frame size and adjust max XDP MTU

Tariq Toukan
2020-04-08T12:57:07Z

On 4/8/2020 2:51 PM, Jesper Dangaard Brouer wrote:
> The mlx4 drivers size of memory backing the RX packet is stored in
> frag_stride. For XDP mode this will be PAGE_SIZE (normally 4096).
> For normal mode frag_stride is 2048.
>
> Also adjust MLX4_EN_MAX_XDP_MTU to take tailroom into account.
>
> Cc: Tariq Toukan <tariqt@mellanox.com>
> Cc: Saeed Mahameed <saeedm@mellanox.com>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 3 ++-
> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> index 43dcbd8214c6..5bd3cd37d50f 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> @@ -51,7 +51,8 @@
> #include "en_port.h"
>
> #define MLX4_EN_MAX_XDP_MTU ((int)(PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN) - \
> - XDP_PACKET_HEADROOM))
> + XDP_PACKET_HEADROOM - \
> + SKB_DATA_ALIGN(sizeof(struct skb_shared_info))))
>
> int mlx4_en_setup_tc(struct net_device *dev, u8 up)
> {
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index db3552f2d087..231f08c0276c 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -683,6 +683,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
> rcu_read_lock();
> xdp_prog = rcu_dereference(ring->xdp_prog);
> xdp.rxq = &ring->xdp_rxq;
> + xdp.frame_sz = priv->frag_info[0].frag_stride;
> doorbell_pending = 0;
>
> /* We assume a 1:1 mapping between CQEs and Rx descriptors, so Rx
>
>

Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Thanks.