mlx5en: Allow binding channels to CPUs when RSS is not enabled.

Submitted by:	Netflix
Reviewed by:	kib
Sponsored by:	Mellanox Technologies // NVIDIA Networking

(cherry picked from commit c8d16d1e084dc14191491e95ce226d3ce8b39275)

3 files changed, 40 insertions, 3 deletions

diff --git a/sys/dev/mlx5/mlx5_en/en.h b/sys/dev/mlx5/mlx5_en/en.h
index c84e2af237b2..8556a4364ddd 100644
--- a/sys/dev/mlx5/mlx5_en/en.h
+++ b/sys/dev/mlx5/mlx5_en/en.h
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2015-2019 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2015-2021 Mellanox Technologies. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -710,7 +710,9 @@ struct mlx5e_params {
   m(+1, u64, diag_general_enable, "diag_general_enable", "0: Disabled 1: Enabled") \
   m(+1, u64, hw_mtu, "hw_mtu", "Current hardware MTU value") \
   m(+1, u64, mc_local_lb, "mc_local_lb", "0: Local multicast loopback enabled 1: Disabled") \
-  m(+1, u64, uc_local_lb, "uc_local_lb", "0: Local unicast loopback enabled 1: Disabled")
+  m(+1, u64, uc_local_lb, "uc_local_lb", "0: Local unicast loopback enabled 1: Disabled") \
+  m(+1, s64, irq_cpu_base, "irq_cpu_base", "-1: Don't bind IRQ 0..NCPU-1: select this base CPU when binding IRQs") \
+  m(+1, s64, irq_cpu_stride, "irq_cpu_stride", "0..NCPU-1: Distance between IRQ vectors when binding them")
 
 #define	MLX5E_PARAMS_NUM (0 MLX5E_PARAMS(MLX5E_STATS_COUNT))
 
diff --git a/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c b/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c
index 4070fe4331a1..f7228989ee04 100644
--- a/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c
+++ b/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2015-2019 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2015-2021 Mellanox Technologies. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -1250,6 +1250,15 @@ mlx5e_ethtool_handler(SYSCTL_HANDLER_ARGS)
 		}
 		break;
 
+	case MLX5_PARAM_OFFSET(irq_cpu_base):
+	case MLX5_PARAM_OFFSET(irq_cpu_stride):
+		if (was_opened) {
+			/* network interface must toggled */
+			mlx5e_close_locked(priv->ifp);
+			mlx5e_open_locked(priv->ifp);
+		}
+		break;
+
 	default:
 		break;
 	}
@@ -1413,6 +1422,8 @@ mlx5e_create_ethtool(struct mlx5e_priv *priv)
 	int i;
 
 	/* set some defaults */
+	priv->params_ethtool.irq_cpu_base = -1;	/* disabled */
+	priv->params_ethtool.irq_cpu_stride = 1;
 	priv->params_ethtool.tx_queue_size_max = 1 << MLX5E_PARAMS_MAXIMUM_LOG_SQ_SIZE;
 	priv->params_ethtool.rx_queue_size_max = 1 << MLX5E_PARAMS_MAXIMUM_LOG_RQ_SIZE;
 	priv->params_ethtool.tx_queue_size = 1 << priv->params.log_sq_size;
diff --git a/sys/dev/mlx5/mlx5_en/mlx5_en_main.c b/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
index b67f382522e7..9345798006f2 100644
--- a/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
+++ b/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
@@ -2446,6 +2446,30 @@ mlx5e_open_channels(struct mlx5e_priv *priv)
 		err = mlx5e_open_channel(priv, cparam, &priv->channel[i]);
 		if (err)
 			goto err_close_channels;
+
+		/* Bind interrupt vectors, if any. */
+		if (priv->params_ethtool.irq_cpu_base > -1) {
+			cpuset_t cpuset;
+			int cpu;
+			int irq;
+			int eqn;
+			int nirq;
+
+			err = mlx5_vector2eqn(priv->mdev, i,
+			    &eqn, &nirq);
+
+			/* error here is non-fatal */
+			if (err != 0)
+				continue;
+
+			irq = priv->mdev->priv.msix_arr[nirq].vector;
+			cpu = (unsigned)(priv->params_ethtool.irq_cpu_base +
+			    i * priv->params_ethtool.irq_cpu_stride) % (unsigned)mp_ncpus;
+
+			CPU_ZERO(&cpuset);
+			CPU_SET(cpu, &cpuset);
+			intr_setaffinity(irq, CPU_WHICH_INTRHANDLER, &cpuset);
+		}
 	}
 
 	for (j = 0; j < priv->params.num_channels; j++) {