net/mlx5: Allocate rate limit table when rate is configured

A device supports 128 rate limiters. A static table allocation consumes
8KB of memory even when rate is not configured.

Instead, allocate the table when at least one rate is configured.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/rl.c b/drivers/net/ethernet/mellanox/mlx5/core/rl.c
index 08792fe701e3a689aa275702933b770f25558d0b..0526e3798c09027394105870cdacf6e2a6a0af56 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/rl.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/rl.c
@@ -117,6 +117,9 @@ static struct mlx5_rl_entry *find_rl_entry(struct mlx5_rl_table *table,
        bool empty_found = false;
        int i;
 
+       lockdep_assert_held(&table->rl_lock);
+       WARN_ON(!table->rl_entry);
+
        for (i = 0; i < table->max_size; i++) {
                if (dedicated) {
                        if (!table->rl_entry[i].refcount)
@@ -172,10 +175,17 @@ bool mlx5_rl_are_equal(struct mlx5_rate_limit *rl_0,
 }
 EXPORT_SYMBOL(mlx5_rl_are_equal);
 
-static int mlx5_rl_table_alloc(struct mlx5_rl_table *table)
+static int mlx5_rl_table_get(struct mlx5_rl_table *table)
 {
        int i;
 
+       lockdep_assert_held(&table->rl_lock);
+
+       if (table->rl_entry) {
+               table->refcount++;
+               return 0;
+       }
+
        table->rl_entry = kcalloc(table->max_size, sizeof(struct mlx5_rl_entry),
                                  GFP_KERNEL);
        if (!table->rl_entry)
@@ -187,13 +197,27 @@ static int mlx5_rl_table_alloc(struct mlx5_rl_table *table)
        for (i = 0; i < table->max_size; i++)
                table->rl_entry[i].index = i + 1;
 
+       table->refcount++;
        return 0;
 }
 
+static void mlx5_rl_table_put(struct mlx5_rl_table *table)
+{
+       lockdep_assert_held(&table->rl_lock);
+       if (--table->refcount)
+               return;
+
+       kfree(table->rl_entry);
+       table->rl_entry = NULL;
+}
+
 static void mlx5_rl_table_free(struct mlx5_core_dev *dev, struct mlx5_rl_table *table)
 {
        int i;
 
+       if (!table->rl_entry)
+               return;
+
        /* Clear all configured rates */
        for (i = 0; i < table->max_size; i++)
                if (table->rl_entry[i].refcount)
@@ -219,8 +243,8 @@ int mlx5_rl_add_rate_raw(struct mlx5_core_dev *dev, void *rl_in, u16 uid,
 {
        struct mlx5_rl_table *table = &dev->priv.rl_table;
        struct mlx5_rl_entry *entry;
-       int err = 0;
        u32 rate;
+       int err;
 
        if (!table->max_size)
                return -EOPNOTSUPP;
@@ -233,13 +257,16 @@ int mlx5_rl_add_rate_raw(struct mlx5_core_dev *dev, void *rl_in, u16 uid,
        }
 
        mutex_lock(&table->rl_lock);
+       err = mlx5_rl_table_get(table);
+       if (err)
+               goto out;
 
        entry = find_rl_entry(table, rl_in, uid, dedicated_entry);
        if (!entry) {
                mlx5_core_err(dev, "Max number of %u rates reached\n",
                              table->max_size);
                err = -ENOSPC;
-               goto out;
+               goto rl_err;
        }
        if (!entry->refcount) {
                /* new rate limit */
@@ -255,14 +282,18 @@ int mlx5_rl_add_rate_raw(struct mlx5_core_dev *dev, void *rl_in, u16 uid,
                                         burst_upper_bound),
                                MLX5_GET(set_pp_rate_limit_context, rl_in,
                                         typical_packet_size));
-                       goto out;
+                       goto rl_err;
                }
 
                entry->dedicated = dedicated_entry;
        }
        mlx5_rl_entry_get(entry);
        *index = entry->index;
+       mutex_unlock(&table->rl_lock);
+       return 0;
 
+rl_err:
+       mlx5_rl_table_put(table);
 out:
        mutex_unlock(&table->rl_lock);
        return err;
@@ -277,6 +308,7 @@ void mlx5_rl_remove_rate_raw(struct mlx5_core_dev *dev, u16 index)
        mutex_lock(&table->rl_lock);
        entry = &table->rl_entry[index - 1];
        mlx5_rl_entry_put(dev, entry);
+       mlx5_rl_table_put(table);
        mutex_unlock(&table->rl_lock);
 }
 EXPORT_SYMBOL(mlx5_rl_remove_rate_raw);
@@ -325,6 +357,7 @@ void mlx5_rl_remove_rate(struct mlx5_core_dev *dev, struct mlx5_rate_limit *rl)
                goto out;
        }
        mlx5_rl_entry_put(dev, entry);
+       mlx5_rl_table_put(table);
 out:
        mutex_unlock(&table->rl_lock);
 }
@@ -333,7 +366,6 @@ EXPORT_SYMBOL(mlx5_rl_remove_rate);
 int mlx5_init_rl_table(struct mlx5_core_dev *dev)
 {
        struct mlx5_rl_table *table = &dev->priv.rl_table;
-       int err;
 
        mutex_init(&table->rl_lock);
        if (!MLX5_CAP_GEN(dev, qos) || !MLX5_CAP_QOS(dev, packet_pacing)) {
@@ -346,10 +378,6 @@ int mlx5_init_rl_table(struct mlx5_core_dev *dev)
        table->max_rate = MLX5_CAP_QOS(dev, packet_pacing_max_rate);
        table->min_rate = MLX5_CAP_QOS(dev, packet_pacing_min_rate);
 
-       err = mlx5_rl_table_alloc(table);
-       if (err)
-               return err;
-
        mlx5_core_info(dev, "Rate limit: %u rates are supported, range: %uMbps to %uMbps\n",
                       table->max_size,
                       table->min_rate >> 10,

diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index a9bd7e3bd554177d765f271f3749d863bee6bdf7..baf38b5a2a8c2e20c97aa7ad1e8fa1dc6f88b020 100644 (file)
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -530,6 +530,7 @@ struct mlx5_rl_table {
        u32                     max_rate;
        u32                     min_rate;
        struct mlx5_rl_entry   *rl_entry;
+       u64 refcount;
 };
 
 struct mlx5_core_roce {