net/mlx5e: Stop NAPI when irq balancer changes affinity

NAPI context keeps rescheduling on same CPU as long as it's busy.
This doesn't give the oppurtunity for changes in irq affinities
to take effect.
Fix that by calling napi_complete_done() upon a change in affinity.
This would stop the NAPI and reschedule it on the new CPU.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 7c046ae8b18ee059f327329a5b9161c1f9bc0a44..1388a1e2f835f42bab7b0da1b70580d9fa766f75 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -582,6 +582,9 @@ struct mlx5e_channel {
        __be32                     mkey_be;
        u8                         num_tc;
 
+       /* data path - accessed per napi poll */
+       struct irq_desc *irq_desc;
+
        /* control */
        struct mlx5e_priv         *priv;
        struct mlx5_core_dev      *mdev;

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index b2f689ec0d7296621852f9e14ca75a828c379e62..20f34131d4e55a470e003891b3569001b567aee1 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -1761,7 +1761,9 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
        struct net_device *netdev = priv->netdev;
        int cpu = mlx5e_get_cpu(priv, ix);
        struct mlx5e_channel *c;
+       unsigned int irq;
        int err;
+       int eqn;
 
        c = kzalloc_node(sizeof(*c), GFP_KERNEL, cpu_to_node(cpu));
        if (!c)
@@ -1778,6 +1780,9 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
        c->num_tc   = params->num_tc;
        c->xdp      = !!params->xdp_prog;
 
+       mlx5_vector2eqn(priv->mdev, ix, &eqn, &irq);
+       c->irq_desc = irq_to_desc(irq);
+
        netif_napi_add(netdev, &c->napi, mlx5e_napi_poll, 64);
 
        err = mlx5e_open_cq(c, icocq_moder, &cparam->icosq_cq, &c->icosq.cq);

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
index 92d9aa1cddd648e7a7ba5be45824b93f8de046b5..e906b754415c2877e799c623ee269280be1c6399 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
@@ -30,8 +30,20 @@
  * SOFTWARE.
  */
 
+#include <linux/irq.h>
 #include "en.h"
 
+static inline bool mlx5e_channel_no_affinity_change(struct mlx5e_channel *c)
+{
+       int current_cpu = smp_processor_id();
+       const struct cpumask *aff;
+       struct irq_data *idata;
+
+       idata = irq_desc_get_irq_data(c->irq_desc);
+       aff = irq_data_get_affinity_mask(idata);
+       return cpumask_test_cpu(current_cpu, aff);
+}
+
 int mlx5e_napi_poll(struct napi_struct *napi, int budget)
 {
        struct mlx5e_channel *c = container_of(napi, struct mlx5e_channel,
@@ -51,8 +63,12 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget)
 
        busy |= c->rq.post_wqes(&c->rq);
 
-       if (busy)
-               return budget;
+       if (busy) {
+               if (likely(mlx5e_channel_no_affinity_change(c)))
+                       return budget;
+               if (work_done == budget)
+                       work_done--;
+       }
 
        if (unlikely(!napi_complete_done(napi, work_done)))
                return work_done;