[RFC net-next v3 2/2] net/mlx5e: Add per queue netdev-genl stats

[Joe Damato]

Add functions to support the netdev-genl per queue stats API.

/cli.py --spec netlink/specs/netdev.yaml \
         --dump qstats-get --json '{"scope": "queue"}'

..snip

 {'ifindex': 7,
  'queue-id': 62,
  'queue-type': 'rx',
  'rx-alloc-fail': 0,
  'rx-bytes': 105965251,
  'rx-packets': 179790},
 {'ifindex': 7,
  'queue-id': 0,
  'queue-type': 'tx',
  'tx-bytes': 9402665,
  'tx-packets': 17551},

..snip

Also tested with the script tools/testing/selftests/drivers/net/stats.py
in several scenarios to ensure stats tallying was correct:

- on boot (default queue counts)
- adjusting queue count up or down (ethtool -L eth0 combined ...)
- adding mqprio TCs

Signed-off-by: Joe Damato <jdamato@xxxxxxxxxx>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 132 ++++++++++++++++++
 1 file changed, 132 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index ce15805ad55a..515c16a88a6c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -39,6 +39,7 @@
 #include <linux/debugfs.h>
 #include <linux/if_bridge.h>
 #include <linux/filter.h>
+#include <net/netdev_queues.h>
 #include <net/page_pool/types.h>
 #include <net/pkt_sched.h>
 #include <net/xdp_sock_drv.h>
@@ -5293,6 +5294,136 @@ static bool mlx5e_tunnel_any_tx_proto_supported(struct mlx5_core_dev *mdev)
 	return (mlx5_vxlan_allowed(mdev->vxlan) || mlx5_geneve_tx_allowed(mdev));
 }
 
+static void mlx5e_get_queue_stats_rx(struct net_device *dev, int i,
+				     struct netdev_queue_stats_rx *stats)
+{
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5e_channel_stats *channel_stats;
+	struct mlx5e_rq_stats *xskrq_stats;
+	struct mlx5e_rq_stats *rq_stats;
+
+	if (mlx5e_is_uplink_rep(priv))
+		return;
+
+	channel_stats = priv->channel_stats[i];
+	xskrq_stats = &channel_stats->xskrq;
+	rq_stats = &channel_stats->rq;
+
+	stats->packets = rq_stats->packets + xskrq_stats->packets;
+	stats->bytes = rq_stats->bytes + xskrq_stats->bytes;
+	stats->alloc_fail = rq_stats->buff_alloc_err +
+			    xskrq_stats->buff_alloc_err;
+}
+
+static void mlx5e_get_queue_stats_tx(struct net_device *dev, int i,
+				     struct netdev_queue_stats_tx *stats)
+{
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5e_channel_stats *channel_stats;
+	struct mlx5e_sq_stats *sq_stats;
+	int ch_ix, tc_ix;
+
+	mutex_lock(&priv->state_lock);
+	txq_ix_to_chtc_ix(&priv->channels.params, i, &ch_ix, &tc_ix);
+	mutex_unlock(&priv->state_lock);
+
+	channel_stats = priv->channel_stats[ch_ix];
+	sq_stats = &channel_stats->sq[tc_ix];
+
+	stats->packets = sq_stats->packets;
+	stats->bytes = sq_stats->bytes;
+}
+
+static void mlx5e_get_base_stats(struct net_device *dev,
+				 struct netdev_queue_stats_rx *rx,
+				 struct netdev_queue_stats_tx *tx)
+{
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	int i, j;
+
+	if (!mlx5e_is_uplink_rep(priv)) {
+		rx->packets = 0;
+		rx->bytes = 0;
+		rx->alloc_fail = 0;
+
+		/* compute stats for deactivated RX queues
+		 *
+		 * if priv->channels.num == 0 the device is down, so compute
+		 * stats for every queue.
+		 *
+		 * otherwise, compute only the queues which have been deactivated.
+		 */
+		mutex_lock(&priv->state_lock);
+		if (priv->channels.num == 0)
+			i = 0;
+		else
+			i = priv->channels.params.num_channels;
+		mutex_unlock(&priv->state_lock);
+
+		for (; i < priv->stats_nch; i++) {
+			struct netdev_queue_stats_rx rx_i = {0};
+
+			mlx5e_get_queue_stats_rx(dev, i, &rx_i);
+
+			rx->packets += rx_i.packets;
+			rx->bytes += rx_i.bytes;
+			rx->alloc_fail += rx_i.alloc_fail;
+		}
+
+		if (priv->rx_ptp_opened) {
+			struct mlx5e_rq_stats *rq_stats = &priv->ptp_stats.rq;
+
+			rx->packets += rq_stats->packets;
+			rx->bytes += rq_stats->bytes;
+		}
+	}
+
+	tx->packets = 0;
+	tx->bytes = 0;
+
+	mutex_lock(&priv->state_lock);
+	for (i = 0; i < priv->stats_nch; i++) {
+		struct mlx5e_channel_stats *channel_stats = priv->channel_stats[i];
+
+		/* while iterating through all channels [0, stats_nch], there
+		 * are two cases to handle:
+		 *
+		 *  1. the channel is available, so sum only the unavailable TCs
+		 *     [mlx5e_get_dcb_num_tc, max_opened_tc).
+		 *
+		 *  2. the channel is unavailable, so sum all TCs [0, max_opened_tc).
+		 */
+		if (i < priv->channels.params.num_channels) {
+			j = mlx5e_get_dcb_num_tc(&priv->channels.params);
+		} else {
+			j = 0;
+		}
+
+		for (; j < priv->max_opened_tc; j++) {
+			struct mlx5e_sq_stats *sq_stats = &channel_stats->sq[j];
+
+			tx->packets += sq_stats->packets;
+			tx->bytes += sq_stats->bytes;
+		}
+	}
+	mutex_unlock(&priv->state_lock);
+
+	if (priv->tx_ptp_opened) {
+		for (j = 0; j < priv->max_opened_tc; j++) {
+			struct mlx5e_sq_stats *sq_stats = &priv->ptp_stats.sq[j];
+
+			tx->packets    += sq_stats->packets;
+			tx->bytes      += sq_stats->bytes;
+		}
+	}
+}
+
+static const struct netdev_stat_ops mlx5e_stat_ops = {
+	.get_queue_stats_rx     = mlx5e_get_queue_stats_rx,
+	.get_queue_stats_tx     = mlx5e_get_queue_stats_tx,
+	.get_base_stats         = mlx5e_get_base_stats,
+};
+
 static void mlx5e_build_nic_netdev(struct net_device *netdev)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
@@ -5310,6 +5441,7 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
 
 	netdev->watchdog_timeo    = 15 * HZ;
 
+	netdev->stat_ops          = &mlx5e_stat_ops;
 	netdev->ethtool_ops	  = &mlx5e_ethtool_ops;
 
 	netdev->vlan_features    |= NETIF_F_SG;
-- 
2.25.1