[PATCH net-next v4 0/3] mlx4: Add support for netdev-genl API

[PATCH net-next v4 0/3] mlx4: Add support for netdev-genl API

[Joe Damato]

Greetings:

Welcome to v4.

This series adds support to mlx4 for the netdev-genl API which makes it
much easier for users and user programs to map NAPI IDs back to
ifindexes, queues, and IRQs. This is extremely useful for a number of
use cases, including epoll-based busy poll.

In addition, this series includes a patch to generate per-queue
statistics using the netlink API, as well.

To facilitate the stats, patch 1/3 adds a field "alloc_fail" to the ring
structure.  incremented by the driver in an appropriate place and used
in patch 3/3 as alloc_fail.

Please note: I do not have access to mlx4 hardware, but I've been
working closely with Martin Karsten from University of Waterloo (CC'd)
who has very graciously tested my patches on their mlx4 hardware (hence
his Tested-by attribution in each commit). His latest research work is
particularly interesting [1] and this series helps to support that (and
future) work.

Martin re-test v4 using Jakub's suggested tool [2] and the
stats.pkt_byte_sum and stats.qstat_by_ifindex tests passed. He also
adjusted the queue count and re-ran test to confirm it still passed even
if the queue count was modified.

[1]: https://dl.acm.org/doi/pdf/10.1145/3626780
[2]: https://lore.kernel.org/lkml/20240423175718.4ad4dc5a@kernel.org/

Thanks,
Joe

v3 -> v4:
 - Patch 1/3: adds alloc_fail field to struct mlx4_en_rx_ring.
   Increments this new field (instead of dropped as in the last version)
   on ENOMEM in mlx4_en_alloc_frags.
 - Patch 2/3: No changes.
 - Patch 3/3:
   - Removed Jakub's Reviewed-by since some number of changes were made.
   - Removed checking the validity of 'i' from both
     mlx4_get_queue_stats_[rt]x as the core code will ensure i is valid
     for us.
   - stats->alloc_fail now uses the new field added in patch 1/3
     instead of dropped.

v2 -> v3:
 - Patch 1/3 no longer sets rx_missed_errors. dropped is still
   incremented on -ENOMEM, though, and reported as alloc_fail in the
   stats API introduced in patch 3/3.
 - Patch 2/3: Added Jakub's Acked-by to the commit message, no
   functional changes.
 - Patch 3/3: Added Jakub's Reviewed-by to the commit message, no
   functional changes.

v1 -> v2:
 - Patch 1/3 now initializes dropped to 0.
 - Patch 2/3 fix use of uninitialized qtype warning.
 - Patch 3/3 includes several changes:
   - mlx4_get_queue_stats_rx and mlx4_get_queue_stats_tx check if i is
     valid before proceeding.
   - All initialization to 0xff for stats fields has been omit. The
     network stack does this before calling into the driver functions, so
     I've adjusted the driver functions to only set values if there is
     data to set, leaving the network stack's 0xff in place if not.
   - mlx4_get_base_stats set all stat fields to 0 individually if there
     are RX and TX queues.


Joe Damato (3):
  net/mlx4: Track RX allocation failures in a stat
  net/mlx4: link NAPI instances to queues and IRQs
  net/mlx4: support per-queue statistics via netlink

 drivers/net/ethernet/mellanox/mlx4/en_cq.c    | 14 ++++
 .../net/ethernet/mellanox/mlx4/en_netdev.c    | 73 +++++++++++++++++++
 drivers/net/ethernet/mellanox/mlx4/en_rx.c    |  4 +-
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h  |  2 +
 4 files changed, 92 insertions(+), 1 deletion(-)

-- 
2.25.1

[PATCH net-next v4 1/3] net/mlx4: Track RX allocation failures in a stat

[Joe Damato]

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;
-- 
2.25.1

Re: [PATCH net-next v4 1/3] net/mlx4: Track RX allocation failures in a stat

[Tariq Toukan]

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...

Re: [PATCH net-next v4 1/3] net/mlx4: Track RX allocation failures in a stat

[Joe Damato]

On Sun, May 12, 2024 at 11:17:09AM +0300, Tariq Toukan wrote:
> 
> 
> 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().

OK, thanks. I'll add that to the v5, alongside any other feedback that
comes in within the next ~24 hours or so.

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

Yea, I see what you mean about the other counters. I think those can
potentially be sent as a 'Fixes' later?

[PATCH net-next v4 2/3] net/mlx4: link NAPI instances to queues and IRQs

[Joe Damato]

Make mlx4 compatible with the newly added netlink queue GET APIs.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/mellanox/mlx4/en_cq.c   | 14 ++++++++++++++
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 1184ac5751e1..461cc2c79c71 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -126,6 +126,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
 		cq_idx = cq_idx % priv->rx_ring_num;
 		rx_cq = priv->rx_cq[cq_idx];
 		cq->vector = rx_cq->vector;
+		irq = mlx4_eq_get_irq(mdev->dev, cq->vector);
 	}
 
 	if (cq->type == RX)
@@ -142,18 +143,23 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
 	if (err)
 		goto free_eq;
 
+	cq->cq_idx = cq_idx;
 	cq->mcq.event = mlx4_en_cq_event;
 
 	switch (cq->type) {
 	case TX:
 		cq->mcq.comp = mlx4_en_tx_irq;
 		netif_napi_add_tx(cq->dev, &cq->napi, mlx4_en_poll_tx_cq);
+		netif_napi_set_irq(&cq->napi, irq);
 		napi_enable(&cq->napi);
+		netif_queue_set_napi(cq->dev, cq_idx, NETDEV_QUEUE_TYPE_TX, &cq->napi);
 		break;
 	case RX:
 		cq->mcq.comp = mlx4_en_rx_irq;
 		netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_rx_cq);
+		netif_napi_set_irq(&cq->napi, irq);
 		napi_enable(&cq->napi);
+		netif_queue_set_napi(cq->dev, cq_idx, NETDEV_QUEUE_TYPE_RX, &cq->napi);
 		break;
 	case TX_XDP:
 		/* nothing regarding napi, it's shared with rx ring */
@@ -189,6 +195,14 @@ void mlx4_en_destroy_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq **pcq)
 void mlx4_en_deactivate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq)
 {
 	if (cq->type != TX_XDP) {
+		enum netdev_queue_type qtype;
+
+		if (cq->type == RX)
+			qtype = NETDEV_QUEUE_TYPE_RX;
+		else
+			qtype = NETDEV_QUEUE_TYPE_TX;
+
+		netif_queue_set_napi(cq->dev, cq->cq_idx, qtype, NULL);
 		napi_disable(&cq->napi);
 		netif_napi_del(&cq->napi);
 	}
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index cd70df22724b..28b70dcc652e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -380,6 +380,7 @@ struct mlx4_en_cq {
 #define MLX4_EN_OPCODE_ERROR	0x1e
 
 	const struct cpumask *aff_mask;
+	int cq_idx;
 };
 
 struct mlx4_en_port_profile {
-- 
2.25.1

[PATCH net-next v4 3/3] net/mlx4: support per-queue statistics via netlink

[Joe Damato]

Make mlx4 compatible with the newly added netlink queue stats API.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
---
 .../net/ethernet/mellanox/mlx4/en_netdev.c    | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 4c089cfa027a..fd79e957b5d8 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -43,6 +43,7 @@
 #include <net/vxlan.h>
 #include <net/devlink.h>
 #include <net/rps.h>
+#include <net/netdev_queues.h>
 
 #include <linux/mlx4/driver.h>
 #include <linux/mlx4/device.h>
@@ -3099,6 +3100,77 @@ void mlx4_en_set_stats_bitmap(struct mlx4_dev *dev,
 	last_i += NUM_PHY_STATS;
 }
 
+static void mlx4_get_queue_stats_rx(struct net_device *dev, int i,
+				    struct netdev_queue_stats_rx *stats)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+	const struct mlx4_en_rx_ring *ring;
+
+	spin_lock_bh(&priv->stats_lock);
+
+	if (!priv->port_up || mlx4_is_master(priv->mdev->dev))
+		goto out_unlock;
+
+	ring = priv->rx_ring[i];
+	stats->packets = READ_ONCE(ring->packets);
+	stats->bytes   = READ_ONCE(ring->bytes);
+	stats->alloc_fail = READ_ONCE(ring->alloc_fail);
+
+out_unlock:
+	spin_unlock_bh(&priv->stats_lock);
+}
+
+static void mlx4_get_queue_stats_tx(struct net_device *dev, int i,
+				    struct netdev_queue_stats_tx *stats)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+	const struct mlx4_en_tx_ring *ring;
+
+	spin_lock_bh(&priv->stats_lock);
+
+	if (!priv->port_up || mlx4_is_master(priv->mdev->dev))
+		goto out_unlock;
+
+	ring = priv->tx_ring[TX][i];
+	stats->packets = READ_ONCE(ring->packets);
+	stats->bytes   = READ_ONCE(ring->bytes);
+
+out_unlock:
+	spin_unlock_bh(&priv->stats_lock);
+}
+
+static void mlx4_get_base_stats(struct net_device *dev,
+				struct netdev_queue_stats_rx *rx,
+				struct netdev_queue_stats_tx *tx)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+
+	spin_lock_bh(&priv->stats_lock);
+
+	if (!priv->port_up || mlx4_is_master(priv->mdev->dev))
+		goto out_unlock;
+
+	if (priv->rx_ring_num) {
+		rx->packets = 0;
+		rx->bytes = 0;
+		rx->alloc_fail = 0;
+	}
+
+	if (priv->tx_ring_num[TX]) {
+		tx->packets = 0;
+		tx->bytes = 0;
+	}
+
+out_unlock:
+	spin_unlock_bh(&priv->stats_lock);
+}
+
+static const struct netdev_stat_ops mlx4_stat_ops = {
+	.get_queue_stats_rx     = mlx4_get_queue_stats_rx,
+	.get_queue_stats_tx     = mlx4_get_queue_stats_tx,
+	.get_base_stats         = mlx4_get_base_stats,
+};
+
 int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 			struct mlx4_en_port_profile *prof)
 {
@@ -3262,6 +3334,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	netif_set_real_num_tx_queues(dev, priv->tx_ring_num[TX]);
 	netif_set_real_num_rx_queues(dev, priv->rx_ring_num);
 
+	dev->stat_ops = &mlx4_stat_ops;
 	dev->ethtool_ops = &mlx4_en_ethtool_ops;
 
 	/*
-- 
2.25.1