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Commit 1db0bcc2 authored by Saeed Mahameed's avatar Saeed Mahameed Committed by Greg Kroah-Hartman
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net/mlx5e: Disable rxhash when CQE compress is enabled 



[ Upstream commit c0194e2d0ef0e5ce5e21a35640d23a706827ae28 ]

When CQE compression is enabled (Multi-host systems), compressed CQEs
might arrive to the driver rx, compressed CQEs don't have a valid hash
offload and the driver already reports a hash value of 0 and invalid hash
type on the skb for compressed CQEs, but this is not good enough.

On a congested PCIe, where CQE compression will kick in aggressively,
gro will deliver lots of out of order packets due to the invalid hash
and this might cause a serious performance drop.

The only valid solution, is to disable rxhash offload at all when CQE
compression is favorable (Multi-host systems).

Fixes: 7219ab34 ("net/mlx5e: CQE compression")
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e0d95806

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

+13 −0
Original line number Diff line number Diff line
@@ -3734,6 +3734,12 @@ static netdev_features_t mlx5e_fix_features(struct net_device *netdev, 
			netdev_warn(netdev, "Disabling LRO, not supported in legacy RQ\n");

	}



	if (MLX5E_GET_PFLAG(params, MLX5E_PFLAG_RX_CQE_COMPRESS)) {

		features &= ~NETIF_F_RXHASH;

		if (netdev->features & NETIF_F_RXHASH)

			netdev_warn(netdev, "Disabling rxhash, not supported when CQE compress is active\n");

	}



	mutex_unlock(&priv->state_lock);



	return features;
@@ -3860,6 +3866,9 @@ int mlx5e_hwstamp_set(struct mlx5e_priv *priv, struct ifreq *ifr) 
	memcpy(&priv->tstamp, &config, sizeof(config));

	mutex_unlock(&priv->state_lock);



	/* might need to fix some features */

	netdev_update_features(priv->netdev);



	return copy_to_user(ifr->ifr_data, &config,

			    sizeof(config)) ? -EFAULT : 0;

}
@@ -4702,6 +4711,10 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev) 
	if (!priv->channels.params.scatter_fcs_en)

		netdev->features  &= ~NETIF_F_RXFCS;



	/* prefere CQE compression over rxhash */

	if (MLX5E_GET_PFLAG(&priv->channels.params, MLX5E_PFLAG_RX_CQE_COMPRESS))

		netdev->features &= ~NETIF_F_RXHASH;



#define FT_CAP(f) MLX5_CAP_FLOWTABLE(mdev, flow_table_properties_nic_receive.f)

	if (FT_CAP(flow_modify_en) &&

	    FT_CAP(modify_root) &&