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Message-ID: <a4efd162-5dc0-4ed1-b875-de12521a6618@gmail.com>
Date: Sun, 12 May 2024 11:17:09 +0300
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Subject: Re: [PATCH net-next v4 1/3] net/mlx4: Track RX allocation failures in
 a stat
To: Joe Damato <jdamato@fastly.com>, linux-kernel@vger.kernel.org,
 netdev@vger.kernel.org
Cc: mkarsten@uwaterloo.ca, nalramli@fastly.com,
 Tariq Toukan <tariqt@nvidia.com>, "David S. Miller" <davem@davemloft.net>,
 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>,
 "open list:MELLANOX MLX4 core VPI driver" <linux-rdma@vger.kernel.org>,
 Tariq Toukan <tariqt@nvidia.com>
References: <20240509205057.246191-1-jdamato@fastly.com>
 <20240509205057.246191-2-jdamato@fastly.com>
Content-Language: en-US
From: Tariq Toukan <ttoukan.linux@gmail.com>
In-Reply-To: <20240509205057.246191-2-jdamato@fastly.com>
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On 09/05/2024 23:50, 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.
> 
> A new field called alloc_fail has been added to struct mlx4_en_rx_ring
> which is now incremented in mlx4_en_rx_ring when -ENOMEM occurs.
> 
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
> ---
>   drivers/net/ethernet/mellanox/mlx4/en_rx.c   | 4 +++-
>   drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 +
>   2 files changed, 4 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..15c57e9517e9 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->alloc_fail++;
>   				return -ENOMEM;
> +			}
>   			ring->rx_alloc_pages++;
>   		}
>   		rx_desc->data[i].addr = cpu_to_be64(frags->dma +
> diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> index efe3f97b874f..cd70df22724b 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> @@ -355,6 +355,7 @@ struct mlx4_en_rx_ring {
>   	unsigned long xdp_tx;
>   	unsigned long xdp_tx_full;
>   	unsigned long dropped;
> +	unsigned long alloc_fail;
>   	int hwtstamp_rx_filter;
>   	cpumask_var_t affinity_mask;
>   	struct xdp_rxq_info xdp_rxq;

Counter should be reset in mlx4_en_clear_stats().

BTW, there are existing counters that are missing there already.
We should add them as well, not related to your series though...