net/mlx5: Let user configure event_eq_size param

Event EQ is an EQ which received the notification of almost all the
events generated by the NIC.
Currently, each event EQ is taking 512KB of memory. This size is not
needed in most use cases, and is critical with large scale. Hence,
allow user to configure the size of the event EQ.

For example to reduce event EQ size to 64, execute::
$ devlink resource set pci/0000:00:0b.0 path /event_eq_size/ size 64
$ devlink dev reload pci/0000:00:0b.0

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Documentation/networking/devlink/mlx5.rst

@@ -57,6 +57,10 @@ Resources
    * - ``comp_eq_size``
      - Control the size of I/O completion EQs.
        * The default value is 1024, and the range is between 64 and 4096.
+   * - ``event_eq_size``
+     - Control the size of the asynchronous control events EQ.
+       * The default value is 4096, and the range is between 64 and 4096.
+
 
 Info versions
 =============

drivers/net/ethernet/mellanox/mlx5/core/devlink.h

@@ -8,6 +8,7 @@
 
 enum mlx5_devlink_resource_id {
 	MLX5_DL_RES_COMP_EQ = 1,
+	MLX5_DL_RES_ASYNC_EQ,
 
 	__MLX5_ID_RES_MAX,
 	MLX5_ID_RES_MAX = __MLX5_ID_RES_MAX - 1,

drivers/net/ethernet/mellanox/mlx5/core/devlink_res.c

@@ -7,6 +7,7 @@
 enum {
 	MLX5_EQ_MIN_SIZE = 64,
 	MLX5_EQ_MAX_SIZE = 4096,
+	MLX5_NUM_ASYNC_EQE = 4096,
 	MLX5_COMP_EQ_SIZE = 1024,
 };
 
@@ -23,13 +24,35 @@ static int comp_eq_res_register(struct mlx5_core_dev *dev)
 					 &comp_eq_size);
 }
 
+static int async_eq_resource_register(struct mlx5_core_dev *dev)
+{
+	struct devlink_resource_size_params async_eq_size;
+	struct devlink *devlink = priv_to_devlink(dev);
+
+	devlink_resource_size_params_init(&async_eq_size, MLX5_EQ_MIN_SIZE,
+					  MLX5_EQ_MAX_SIZE, 1, DEVLINK_RESOURCE_UNIT_ENTRY);
+	return devlink_resource_register(devlink, "event_eq_size",
+					 MLX5_NUM_ASYNC_EQE, MLX5_DL_RES_ASYNC_EQ,
+					 DEVLINK_RESOURCE_ID_PARENT_TOP,
+					 &async_eq_size);
+}
+
 void mlx5_devlink_res_register(struct mlx5_core_dev *dev)
 {
 	int err;
 
 	err = comp_eq_res_register(dev);
 	if (err)
-		mlx5_core_err(dev, "Failed to register resources, err = %d\n", err);
+		goto err_msg;
+
+	err = async_eq_resource_register(dev);
+	if (err)
+		goto err;
+	return;
+err:
+	devlink_resources_unregister(priv_to_devlink(dev), NULL);
+err_msg:
+	mlx5_core_err(dev, "Failed to register resources, err = %d\n", err);
 }
 
 void mlx5_devlink_res_unregister(struct mlx5_core_dev *dev)
@@ -39,6 +62,7 @@ void mlx5_devlink_res_unregister(struct mlx5_core_dev *dev)
 
 static const size_t default_vals[MLX5_ID_RES_MAX + 1] = {
 	[MLX5_DL_RES_COMP_EQ] = MLX5_COMP_EQ_SIZE,
+	[MLX5_DL_RES_ASYNC_EQ] = MLX5_NUM_ASYNC_EQE,
 };
 
 size_t mlx5_devlink_res_size(struct mlx5_core_dev *dev, enum mlx5_devlink_resource_id id)

drivers/net/ethernet/mellanox/mlx5/core/eq.c

@@ -647,7 +647,7 @@ static int create_async_eqs(struct mlx5_core_dev *dev)
 
 	param = (struct mlx5_eq_param) {
 		.irq_index = MLX5_IRQ_EQ_CTRL,
-		.nent = MLX5_NUM_ASYNC_EQE,
+		.nent = mlx5_devlink_res_size(dev, MLX5_DL_RES_ASYNC_EQ),
 	};
 
 	gather_async_events_mask(dev, param.mask);

include/linux/mlx5/eq.h

@@ -5,7 +5,6 @@
 #define MLX5_CORE_EQ_H
 
 #define MLX5_NUM_CMD_EQE   (32)
-#define MLX5_NUM_ASYNC_EQE (0x1000)
 #define MLX5_NUM_SPARE_EQE (0x80)
 
 struct mlx5_eq;