net/mlx4_en: Use minimal rx and tx ring sizes on kdump kernel

When memory is limited (on kdump kernel), reduce size of rx and tx rings.
Also reduce the number of rx rings.
Signed-off-by: Alaa Hleihel <alaa@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -167,8 +167,13 @@ static void mlx4_en_get_profile(struct mlx4_en_dev *mdev)
 		params->prof[i].rx_ppp = pfcrx;
 		params->prof[i].tx_pause = !(pfcrx || pfctx);
 		params->prof[i].tx_ppp = pfctx;
+		if (mlx4_low_memory_profile()) {
+			params->prof[i].tx_ring_size = MLX4_EN_MIN_TX_SIZE;
+			params->prof[i].rx_ring_size = MLX4_EN_MIN_RX_SIZE;
+		} else {
 			params->prof[i].tx_ring_size = MLX4_EN_DEF_TX_RING_SIZE;
 			params->prof[i].rx_ring_size = MLX4_EN_DEF_RX_RING_SIZE;
+		}
 		params->prof[i].num_up = MLX4_EN_NUM_UP_LOW;
 		params->prof[i].num_tx_rings_p_up = params->max_num_tx_rings_p_up;
 		params->prof[i].tx_ring_num[TX] = params->max_num_tx_rings_p_up *

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

@@ -72,7 +72,7 @@
 #define MLX4_EN_PAGE_SIZE	(1 << MLX4_EN_PAGE_SHIFT)
 #define DEF_RX_RINGS		16
 #define MAX_RX_RINGS		128
-#define MIN_RX_RINGS		4
+#define MIN_RX_RINGS		1
 #define LOG_TXBB_SIZE		6
 #define TXBB_SIZE		BIT(LOG_TXBB_SIZE)
 #define HEADROOM		(2048 / TXBB_SIZE + 1)