[PATCH net-next 3/3] net/mlx5: add debugfs stats for doorbell dma pools

From: Tariq Toukan

Date: Thu Jul 23 2026 - 03:28:58 EST


From: Nimrod Oren <noren@xxxxxxxxxx>

Add a debugfs file exposing per-node DMA pool usage for doorbell
allocations.

# cat /sys/kernel/debug/mlx5/<dev>/db_dma_pools
node block_size used_blocks allocated_blocks
0 64 0 0
1 64 0 0

Signed-off-by: Nimrod Oren <noren@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
.../net/ethernet/mellanox/mlx5/core/alloc.c | 30 +++++++++++++++++++
include/linux/mlx5/driver.h | 1 +
2 files changed, 31 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/alloc.c b/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
index 3975c726d35c..60ff413999f7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
@@ -437,11 +437,37 @@ void mlx5_frag_buf_free(struct mlx5_core_dev *dev, struct mlx5_frag_buf *buf)
}
EXPORT_SYMBOL_GPL(mlx5_frag_buf_free);

+static int mlx5_db_dma_pools_debugfs_show(struct seq_file *file, void *priv)
+{
+ struct mlx5_core_dev *dev = file->private;
+ int node;
+
+ mlx5_dma_pools_debugfs_print_header(file);
+
+ if (!dev->priv.db_node_pools)
+ return 0;
+
+ for_each_node_state(node, N_POSSIBLE) {
+ struct mlx5_dma_pool *pool = dev->priv.db_node_pools[node];
+
+ if (!pool)
+ continue;
+
+ mlx5_dma_pool_debugfs_stats_print(file, pool);
+ }
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(mlx5_db_dma_pools_debugfs);
+
void mlx5_db_pools_cleanup(struct mlx5_core_dev *dev)
{
struct mlx5_priv *priv = &dev->priv;
int node;

+ debugfs_remove(priv->dbg.db_dma_pools_debugfs);
+ priv->dbg.db_dma_pools_debugfs = NULL;
+
for_each_node_state(node, N_POSSIBLE)
if (priv->db_node_pools[node])
mlx5_dma_pool_destroy(priv->db_node_pools[node]);
@@ -471,6 +497,10 @@ int mlx5_db_pools_init(struct mlx5_core_dev *dev)
priv->db_node_pools[node] = pool;
}

+ priv->dbg.db_dma_pools_debugfs =
+ debugfs_create_file("db_dma_pools", 0444, priv->dbg.dbg_root,
+ dev, &mlx5_db_dma_pools_debugfs_fops);
+
return 0;
}

diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index 2c56bb1d676d..83d0a83bbfbc 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -548,6 +548,7 @@ struct mlx5_debugfs_entries {
struct dentry *cq_debugfs;
struct dentry *cmdif_debugfs;
struct dentry *frag_buf_dma_pools_debugfs;
+ struct dentry *db_dma_pools_debugfs;
struct dentry *pages_debugfs;
struct dentry *lag_debugfs;
};
--
2.44.0