net/mlx5: Let user configure io_eq_size param

Currently, each I/O EQ is taking 128KB of memory. This size
is not needed in all use cases, and is critical with large scale.
Hence, allow user to configure the size of I/O EQs.

For example, to reduce I/O EQ size to 64, execute:
$ devlink resource set pci/0000:00:0b.0 path /io_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

@@ -46,6 +46,18 @@ parameters.
 
 The ``mlx5`` driver supports reloading via ``DEVLINK_CMD_RELOAD``
 
+Resources
+=========
+
+.. list-table:: Driver-specific resources implemented
+   :widths: 5 5 5 85
+
+   * - Name
+     - Description
+   * - ``comp_eq_size``
+     - Control the size of I/O completion EQs.
+       * The default value is 1024, and the range is between 64 and 4096.
+
 Info versions
 =============
 

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -16,7 +16,7 @@ mlx5_core-y :=	main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
 		transobj.o vport.o sriov.o fs_cmd.o fs_core.o pci_irq.o \
 		fs_counters.o fs_ft_pool.o rl.o lag/lag.o dev.o events.o wq.o lib/gid.o \
 		lib/devcom.o lib/pci_vsc.o lib/dm.o lib/fs_ttc.o diag/fs_tracepoint.o \
-		diag/fw_tracer.o diag/crdump.o devlink.o diag/rsc_dump.o \
+		diag/fw_tracer.o diag/crdump.o devlink.o devlink_res.o diag/rsc_dump.o \
 		fw_reset.o qos.o lib/tout.o
 
 #

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

@@ -6,6 +6,13 @@
 
 #include <net/devlink.h>
 
+enum mlx5_devlink_resource_id {
+	MLX5_DL_RES_COMP_EQ = 1,
+
+	__MLX5_ID_RES_MAX,
+	MLX5_ID_RES_MAX = __MLX5_ID_RES_MAX - 1,
+};
+
 enum mlx5_devlink_param_id {
 	MLX5_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
 	MLX5_DEVLINK_PARAM_ID_FLOW_STEERING_MODE,
@@ -31,6 +38,10 @@ int mlx5_devlink_trap_get_num_active(struct mlx5_core_dev *dev);
 int mlx5_devlink_traps_get_action(struct mlx5_core_dev *dev, int trap_id,
 				  enum devlink_trap_action *action);
 
+void mlx5_devlink_res_register(struct mlx5_core_dev *dev);
+void mlx5_devlink_res_unregister(struct mlx5_core_dev *dev);
+size_t mlx5_devlink_res_size(struct mlx5_core_dev *dev, enum mlx5_devlink_resource_id id);
+
 struct devlink *mlx5_devlink_alloc(struct device *dev);
 void mlx5_devlink_free(struct devlink *devlink);
 int mlx5_devlink_register(struct devlink *devlink);

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

+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2021, NVIDIA CORPORATION & AFFILIATES. */
+
+#include "devlink.h"
+#include "mlx5_core.h"
+
+enum {
+	MLX5_EQ_MIN_SIZE = 64,
+	MLX5_EQ_MAX_SIZE = 4096,
+	MLX5_COMP_EQ_SIZE = 1024,
+};
+
+static int comp_eq_res_register(struct mlx5_core_dev *dev)
+{
+	struct devlink_resource_size_params comp_eq_size;
+	struct devlink *devlink = priv_to_devlink(dev);
+
+	devlink_resource_size_params_init(&comp_eq_size, MLX5_EQ_MIN_SIZE,
+					  MLX5_EQ_MAX_SIZE, 1, DEVLINK_RESOURCE_UNIT_ENTRY);
+	return devlink_resource_register(devlink, "io_eq_size", MLX5_COMP_EQ_SIZE,
+					 MLX5_DL_RES_COMP_EQ,
+					 DEVLINK_RESOURCE_ID_PARENT_TOP,
+					 &comp_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);
+}
+
+void mlx5_devlink_res_unregister(struct mlx5_core_dev *dev)
+{
+	devlink_resources_unregister(priv_to_devlink(dev), NULL);
+}
+
+static const size_t default_vals[MLX5_ID_RES_MAX + 1] = {
+	[MLX5_DL_RES_COMP_EQ] = MLX5_COMP_EQ_SIZE,
+};
+
+size_t mlx5_devlink_res_size(struct mlx5_core_dev *dev, enum mlx5_devlink_resource_id id)
+{
+	struct devlink *devlink = priv_to_devlink(dev);
+	u64 size;
+	int err;
+
+	err = devlink_resource_size_get(devlink, id, &size);
+	if (!err)
+		return size;
+	mlx5_core_err(dev, "Failed to get param. using default. err = %d, id = %u\n",
+		      err, id);
+	return default_vals[id];
+}

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

@@ -19,6 +19,7 @@
 #include "lib/clock.h"
 #include "diag/fw_tracer.h"
 #include "mlx5_irq.h"
+#include "devlink.h"
 
 enum {
 	MLX5_EQE_OWNER_INIT_VAL	= 0x1,
@@ -807,7 +808,7 @@ static int create_comp_eqs(struct mlx5_core_dev *dev)
 
 	INIT_LIST_HEAD(&table->comp_eqs_list);
 	ncomp_eqs = table->num_comp_eqs;
-	nent = MLX5_COMP_EQ_SIZE;
+	nent = mlx5_devlink_res_size(dev, MLX5_DL_RES_COMP_EQ);
 	for (i = 0; i < ncomp_eqs; i++) {
 		struct mlx5_eq_param param = {};
 		int vecidx = i;

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

@@ -922,6 +922,8 @@ static int mlx5_init_once(struct mlx5_core_dev *dev)
 	dev->hv_vhca = mlx5_hv_vhca_create(dev);
 	dev->rsc_dump = mlx5_rsc_dump_create(dev);
 
+	mlx5_devlink_res_register(dev);
+
 	return 0;
 
 err_sf_table_cleanup:
@@ -957,6 +959,7 @@ static int mlx5_init_once(struct mlx5_core_dev *dev)
 
 static void mlx5_cleanup_once(struct mlx5_core_dev *dev)
 {
+	mlx5_devlink_res_unregister(dev);
 	mlx5_rsc_dump_destroy(dev);
 	mlx5_hv_vhca_destroy(dev->hv_vhca);
 	mlx5_fw_tracer_destroy(dev->tracer);

include/linux/mlx5/driver.h

@@ -797,10 +797,6 @@ struct mlx5_db {
 	int			index;
 };
 
-enum {
-	MLX5_COMP_EQ_SIZE = 1024,
-};
-
 enum {
 	MLX5_PTYS_IB = 1 << 0,
 	MLX5_PTYS_EN = 1 << 2,