net/mlx4_en: Reduce memory consumption on kdump kernel

When memory is limited, reduce number of rx and tx rings.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_main.c

@@ -129,8 +129,10 @@ static int mlx4_en_get_profile(struct mlx4_en_dev *mdev)
 	int i;
 
 	params->udp_rss = udp_rss;
-	params->num_tx_rings_p_up = min_t(int, num_online_cpus(),
-			MLX4_EN_MAX_TX_RING_P_UP);
+	params->num_tx_rings_p_up = mlx4_low_memory_profile() ?
+		MLX4_EN_MIN_TX_RING_P_UP :
+		min_t(int, num_online_cpus(), MLX4_EN_MAX_TX_RING_P_UP);
+
 	if (params->udp_rss && !(mdev->dev->caps.flags
 					& MLX4_DEV_CAP_FLAG_UDP_RSS)) {
 		mlx4_warn(mdev, "UDP RSS is not supported on this device\n");

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -335,8 +335,9 @@ void mlx4_en_set_num_rx_rings(struct mlx4_en_dev *mdev)
 					   dev->caps.comp_pool/
 					   dev->caps.num_ports) - 1;
 
-		num_rx_rings = min_t(int, num_of_eqs,
-				     netif_get_num_default_rss_queues());
+		num_rx_rings = mlx4_low_memory_profile() ? MIN_RX_RINGS :
+			min_t(int, num_of_eqs,
+			      netif_get_num_default_rss_queues());
 		mdev->profile.prof[i].rx_ring_num =
 			rounddown_pow_of_two(num_rx_rings);
 	}

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -121,6 +121,7 @@ enum {
 #define MLX4_EN_MIN_TX_SIZE	(4096 / TXBB_SIZE)
 
 #define MLX4_EN_SMALL_PKT_SIZE		64
+#define MLX4_EN_MIN_TX_RING_P_UP	1
 #define MLX4_EN_MAX_TX_RING_P_UP	32
 #define MLX4_EN_NUM_UP			8
 #define MLX4_EN_DEF_TX_RING_SIZE	512