[net-next 16/17] net/mlx5e: Stop NAPI when irq balancer changes affinity
From: Saeed Mahameed <hidden>
Date: 2017-09-03 04:22:15
Subsystem:
mellanox ethernet driver (mlx5e), mellanox mlx5 core vpi driver, networking drivers, the rest · Maintainers:
Saeed Mahameed, Tariq Toukan, Mark Bloch, Leon Romanovsky, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Tariq Toukan <redacted> 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 <redacted> Signed-off-by: Saeed Mahameed <redacted> --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 3 +++ drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 5 +++++ drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 20 ++++++++++++++++++-- 3 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 7c046ae8b18e..1388a1e2f835 100644
--- 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 b2f689ec0d72..20f34131d4e5 100644
--- 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 92d9aa1cddd6..e906b754415c 100644
--- 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;
--
2.13.0