We have observed a sudden spike in rx/tx_packets and rx/tx_bytes
reported under /proc/net/dev. It seems there is a race in
mlx5e_update_stats() and some of the get-stats functions (the
one that we hit is the mlx5e_get_stats() which is called
by ndo_get_stats64()).
In particular, the very first thing mlx5e_update_sw_counters()
does is 'memset(s, 0, sizeof(*s))'. For example, if mlx5e_get_stats()
is unlucky at one point, rx_bytes and rx_packets could be 0. One second
later, a normal (and much bigger than 0) value will be reported.
This patch is not meant to be a proper fix. It merely tries
to show what I have suspected and start the discussion.
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
Cc: Saeed Mahameed <sae...@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c | 7 +++++--
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 3 +++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index a004a5a1a4c2..d24916f720bb 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -313,7 +313,6 @@ static void mlx5e_get_ethtool_stats(struct net_device *dev,
mutex_lock(&priv->state_lock);
if (test_bit(MLX5E_STATE_OPENED, &priv->state))
mlx5e_update_stats(priv);
- mutex_unlock(&priv->state_lock);
for (i = 0; i < NUM_SW_COUNTERS; i++)
data[idx++] = MLX5E_READ_CTR64_CPU(&priv->stats.sw,
@@ -378,8 +377,10 @@ static void mlx5e_get_ethtool_stats(struct net_device *dev,
data[idx++] =
MLX5E_READ_CTR64_CPU(mlx5_priv->pme_stats.error_counters,
mlx5e_pme_error_desc, i);
- if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
+ if (!test_bit(MLX5E_STATE_OPENED, &priv->state)) {
+ mutex_unlock(&priv->state_lock);
return;
+ }
/* per channel counters */
for (i = 0; i < priv->params.num_channels; i++)
@@ -393,6 +394,8 @@ static void mlx5e_get_ethtool_stats(struct net_device *dev,
for (j = 0; j < NUM_SQ_STATS; j++)
data[idx++] =
MLX5E_READ_CTR64_CPU(&priv->channel[i]->sq[tc].stats,
sq_stats_desc, j);
+
+ mutex_unlock(&priv->state_lock);
}
static u32 mlx5e_rx_wqes_to_packets(struct mlx5e_priv *priv, int rq_wq_type,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 66c133757a5e..a4c100bea541 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -2748,6 +2748,8 @@ mlx5e_get_stats(struct net_device *dev, struct
rtnl_link_stats64 *stats)
struct mlx5e_vport_stats *vstats = &priv->stats.vport;
struct mlx5e_pport_stats *pstats = &priv->stats.pport;
+ mutex_lock(&priv->state_lock);
+
if (mlx5e_is_uplink_rep(priv)) {
stats->rx_packets = PPORT_802_3_GET(pstats,
a_frames_received_ok);
stats->rx_bytes = PPORT_802_3_GET(pstats,
a_octets_received_ok);
@@ -2783,6 +2785,7 @@ mlx5e_get_stats(struct net_device *dev, struct
rtnl_link_stats64 *stats)
stats->multicast =
VPORT_COUNTER_GET(vstats, received_eth_multicast.packets);
+ mutex_unlock(&priv->state_lock);
}
static void mlx5e_set_rx_mode(struct net_device *dev)
--
2.9.3
