Commit fa691d0c authored by Lama Kayal's avatar Lama Kayal Committed by Saeed Mahameed
Browse files

net/mlx5e: Allocate per-channel stats dynamically at first usage 



Make stats allocation per-channel dynamic on demand, at channel open
operation.

Previously the stats array was pre-allocated for the maximum possible
number of channels. Here we defer the per-channel stats instance allocation
upon its first usage, so that it's allocated only if really needed.

Allocating stats on demand helps maintain a more memory-efficient code,
as we're saving memory when the used number of channels is smaller than
the maximum.

The stats memory instances are still freed in mlx5e_priv_arrays_free(),
so that they are persistent to channels' closure.

Memory size allocated for struct mlx5e_channel_stats is 3648 bytes.
If maximum number of channel stands for 64, the total memory space
allocated for stats is 3648x64 = 228K bytes. In scenarios where the
number of channels in use is significantly smaller than maximum number,
the memory saved can be remarkable.

Signed-off-by: default avatarLama Kayal <lkayal@nvidia.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent be98737a

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

+28 −13
Original line number Diff line number Diff line
@@ -2176,6 +2176,30 @@ static u8 mlx5e_enumerate_lag_port(struct mlx5_core_dev *mdev, int ix) 
	return (ix + port_aff_bias) % mlx5e_get_num_lag_ports(mdev);

}



static int mlx5e_channel_stats_alloc(struct mlx5e_priv *priv, int ix, int cpu)

{

	if (ix > priv->stats_nch)  {

		netdev_warn(priv->netdev, "Unexpected channel stats index %d > %d\n", ix,

			    priv->stats_nch);

		return -EINVAL;

	}



	if (priv->channel_stats[ix])

		return 0;



	/* Asymmetric dynamic memory allocation.

	 * Freed in mlx5e_priv_arrays_free, not on channel closure.

	 */

	mlx5e_dbg(DRV, priv, "Creating channel stats %d\n", ix);

	priv->channel_stats[ix] = kvzalloc_node(sizeof(**priv->channel_stats),

						GFP_KERNEL, cpu_to_node(cpu));

	if (!priv->channel_stats[ix])

		return -ENOMEM;

	priv->stats_nch++;



	return 0;

}



static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,

			      struct mlx5e_params *params,

			      struct mlx5e_channel_param *cparam,
@@ -2193,6 +2217,10 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix, 
	if (err)

		return err;



	err = mlx5e_channel_stats_alloc(priv, ix, cpu);

	if (err)

		return err;



	c = kvzalloc_node(sizeof(*c), GFP_KERNEL, cpu_to_node(cpu));

	if (!c)

		return -ENOMEM;
@@ -5153,7 +5181,6 @@ int mlx5e_priv_init(struct mlx5e_priv *priv, 
	priv->netdev      = netdev;

	priv->msglevel    = MLX5E_MSG_LEVEL;

	priv->max_nch     = nch;

	priv->stats_nch   = nch;

	priv->max_opened_tc = 1;



	if (!alloc_cpumask_var(&priv->scratchpad.cpumask, GFP_KERNEL))
@@ -5196,20 +5223,8 @@ int mlx5e_priv_init(struct mlx5e_priv *priv, 
	if (!priv->channel_stats)

		goto err_free_channel_tc2realtxq;



	for (i = 0; i < priv->stats_nch; i++) {

		priv->channel_stats[i] = kvzalloc_node(sizeof(**priv->channel_stats),

						       GFP_KERNEL, node);

		if (!priv->channel_stats[i])

			goto err_free_channel_stats;

	}



	return 0;



err_free_channel_stats:

	while (--i >= 0)

		kvfree(priv->channel_stats[i]);

	kfree(priv->channel_stats);

	i = nch;

err_free_channel_tc2realtxq:

	while (--i >= 0)

		kfree(priv->channel_tc2realtxq[i]);