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From: Joe Damato <jdamato@fastly.com>
To: linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Cc: nalramli@fastly.com,
	mkarsten@uwaterloo.ca,
	Joe Damato <jdamato@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>,
	linux-rdma@vger.kernel.org (open list:MELLANOX MLX4 core VPI driver)
Subject: [PATCH net-next v6 1/3] net/mlx4: Track RX allocation failures in a stat
Date: Tue, 28 May 2024 18:11:36 +0000
Message-Id: <20240528181139.515070-2-jdamato@fastly.com>
In-Reply-To: <20240528181139.515070-1-jdamato@fastly.com>
References: <20240528181139.515070-1-jdamato@fastly.com>
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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>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 1 +
 drivers/net/ethernet/mellanox/mlx4/en_rx.c     | 4 +++-
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h   | 1 +
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 4c089cfa027a..4d2f8c458346 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2073,6 +2073,7 @@ static void mlx4_en_clear_stats(struct net_device *dev)
 		priv->rx_ring[i]->csum_ok = 0;
 		priv->rx_ring[i]->csum_none = 0;
 		priv->rx_ring[i]->csum_complete = 0;
+		priv->rx_ring[i]->alloc_fail = 0;
 	}
 }
 
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;
-- 
2.25.1