On Thu, May 02, 2024 at 09:26:25PM +0000, Joe Damato wrote:
> mlx4_en_alloc_frags currently returns -ENOMEM when mlx4_alloc_page
> fails but does not increment a stat field when this occurs.
>
> struct mlx4_en_rx_ring has a dropped field which is tabulated in
> mlx4_en_DUMP_ETH_STATS, but never incremented by the driver.
>
> This change modifies mlx4_en_alloc_frags to increment mlx4_en_rx_ring's
> dropped field for the -ENOMEM case.
>
> Signed-off-by: Joe Damato <jdamato@xxxxxxxxxx>
> Tested-by: Martin Karsten <mkarsten@xxxxxxxxxxxx>
> ---
> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index 8328df8645d5..573ae10300c7 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -82,8 +82,10 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv,
>
> for (i = 0; i < priv->num_frags; i++, frags++) {
> if (!frags->page) {
> - if (mlx4_alloc_page(priv, frags, gfp))
> + if (mlx4_alloc_page(priv, frags, gfp)) {
> + ring->dropped++;
> return -ENOMEM;
> + }
Correct me if I'm wrong, but ring->dropped is added to rx_dropped stats in
mlx4_en_DUMP_ETH_STATS(). You have already established with Jakub that
allocation error does not mean dropped packet, but the counter contributes to
dropped packets stats.
Also, I do not think that using a `dropped` counter for something that does not
neccessarily result in a dropped packet is plain confusing.
> ring->rx_alloc_pages++;
> }
> rx_desc->data[i].addr = cpu_to_be64(frags->dma +
> --
> 2.25.1
>
>
