mlx4_en: Moving to Interrupts for TX completions

Moving to interrupts instead of polling fpr TX completions
Avoiding situations where skb can be held in by the driver for
a long time (till timer expires).
The change is also necessary for supporting BQL.

Removing comp_lock that was required because we could handle TX
completions from several contexts: Interrupts, timer, polling.
Now there is only interrupts

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 00b8127..908a460 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -124,11 +124,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
        cq->mcq.comp  = cq->is_tx ? mlx4_en_tx_irq : mlx4_en_rx_irq;
        cq->mcq.event = mlx4_en_cq_event;
 
-       if (cq->is_tx) {
-               init_timer(&cq->timer);
-               cq->timer.function = mlx4_en_poll_tx_cq;
-               cq->timer.data = (unsigned long) cq;
-       } else {
+       if (!cq->is_tx) {
                netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_rx_cq, 64);
                napi_enable(&cq->napi);
        }
@@ -151,16 +147,12 @@ void mlx4_en_destroy_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq)
 
 void mlx4_en_deactivate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq)
 {
-       struct mlx4_en_dev *mdev = priv->mdev;
-
-       if (cq->is_tx)
-               del_timer(&cq->timer);
-       else {
+       if (!cq->is_tx) {
                napi_disable(&cq->napi);
                netif_napi_del(&cq->napi);
        }
 
-       mlx4_cq_free(mdev->dev, &cq->mcq);
+       mlx4_cq_free(priv->mdev->dev, &cq->mcq);
 }
 
 /* Set rx cq moderation parameters */

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index bfcfd8a..35ad097 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -667,6 +667,10 @@ int mlx4_en_start_port(struct net_device *dev)
                        mlx4_en_deactivate_cq(priv, cq);
                        goto tx_err;
                }
+
+               /* Arm CQ for TX completions */
+               mlx4_en_arm_cq(priv, cq);
+
                /* Set initial ownership of all Tx TXBBs to SW (1) */
                for (j = 0; j < tx_ring->buf_size; j += STAMP_STRIDE)
                        *((u32 *) (tx_ring->buf + j)) = 0xffffffff;

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index d9bab53..2d49342 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -67,8 +67,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 
        inline_thold = min(inline_thold, MAX_INLINE);
 
-       spin_lock_init(&ring->comp_lock);
-
        tmp = size * sizeof(struct mlx4_en_tx_info);
        ring->tx_info = vmalloc(tmp);
        if (!ring->tx_info)
@@ -377,41 +375,12 @@ void mlx4_en_tx_irq(struct mlx4_cq *mcq)
 {
        struct mlx4_en_cq *cq = container_of(mcq, struct mlx4_en_cq, mcq);
        struct mlx4_en_priv *priv = netdev_priv(cq->dev);
-       struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
 
-       if (!spin_trylock(&ring->comp_lock))
-               return;
        mlx4_en_process_tx_cq(cq->dev, cq);
-       mod_timer(&cq->timer, jiffies + 1);
-       spin_unlock(&ring->comp_lock);
+       mlx4_en_arm_cq(priv, cq);
 }
 
 
-void mlx4_en_poll_tx_cq(unsigned long data)
-{
-       struct mlx4_en_cq *cq = (struct mlx4_en_cq *) data;
-       struct mlx4_en_priv *priv = netdev_priv(cq->dev);
-       struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
-       u32 inflight;
-
-       INC_PERF_COUNTER(priv->pstats.tx_poll);
-
-       if (!spin_trylock_irq(&ring->comp_lock)) {
-               mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
-               return;
-       }
-       mlx4_en_process_tx_cq(cq->dev, cq);
-       inflight = (u32) (ring->prod - ring->cons - ring->last_nr_txbb);
-
-       /* If there are still packets in flight and the timer has not already
-        * been scheduled by the Tx routine then schedule it here to guarantee
-        * completion processing of these packets */
-       if (inflight && priv->port_up)
-               mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
-
-       spin_unlock_irq(&ring->comp_lock);
-}
-
 static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
                                                      struct mlx4_en_tx_ring *ring,
                                                      u32 index,
@@ -440,25 +409,6 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
        return ring->buf + index * TXBB_SIZE;
 }
 
-static inline void mlx4_en_xmit_poll(struct mlx4_en_priv *priv, int tx_ind)
-{
-       struct mlx4_en_cq *cq = &priv->tx_cq[tx_ind];
-       struct mlx4_en_tx_ring *ring = &priv->tx_ring[tx_ind];
-       unsigned long flags;
-
-       /* If we don't have a pending timer, set one up to catch our recent
-          post in case the interface becomes idle */
-       if (!timer_pending(&cq->timer))
-               mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
-
-       /* Poll the CQ every mlx4_en_TX_MODER_POLL packets */
-       if ((++ring->poll_cnt & (MLX4_EN_TX_POLL_MODER - 1)) == 0)
-               if (spin_trylock_irqsave(&ring->comp_lock, flags)) {
-                       mlx4_en_process_tx_cq(priv->dev, cq);
-                       spin_unlock_irqrestore(&ring->comp_lock, flags);
-               }
-}
-
 static int is_inline(struct sk_buff *skb, void **pfrag)
 {
        void *ptr;
@@ -590,7 +540,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_en_tx_ring *ring;
-       struct mlx4_en_cq *cq;
        struct mlx4_en_tx_desc *tx_desc;
        struct mlx4_wqe_data_seg *data;
        struct skb_frag_struct *frag;
@@ -638,9 +587,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                ring->blocked = 1;
                priv->port_stats.queue_stopped++;
 
-               /* Use interrupts to find out when queue opened */
-               cq = &priv->tx_cq[tx_ind];
-               mlx4_en_arm_cq(priv, cq);
                return NETDEV_TX_BUSY;
        }
 
@@ -788,9 +734,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                iowrite32be(ring->doorbell_qpn, ring->bf.uar->map + MLX4_SEND_DOORBELL);
        }
 
-       /* Poll CQ here */
-       mlx4_en_xmit_poll(priv, tx_ind);
-
        return NETDEV_TX_OK;
 
 tx_drop:

diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 47e1c0f..0feafc5 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -122,7 +122,7 @@ enum {
 #define MLX4_EN_RX_COAL_TARGET 44
 #define MLX4_EN_RX_COAL_TIME   0x10
 
-#define MLX4_EN_TX_COAL_PKTS   5
+#define MLX4_EN_TX_COAL_PKTS   16
 #define MLX4_EN_TX_COAL_TIME   0x80
 
 #define MLX4_EN_RX_RATE_LOW            400000
@@ -255,7 +255,6 @@ struct mlx4_en_tx_ring {
        unsigned long bytes;
        unsigned long packets;
        unsigned long tx_csum;
-       spinlock_t comp_lock;
        struct mlx4_bf bf;
        bool bf_enabled;
 };
@@ -308,8 +307,6 @@ struct mlx4_en_cq {
        spinlock_t              lock;
        struct net_device      *dev;
        struct napi_struct      napi;
-       /* Per-core Tx cq processing support */
-       struct timer_list timer;
        int size;
        int buf_size;
        unsigned vector;
@@ -530,7 +527,6 @@ void mlx4_en_deactivate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq);
 int mlx4_en_set_cq_moder(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq);
 int mlx4_en_arm_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq);
 
-void mlx4_en_poll_tx_cq(unsigned long data);
 void mlx4_en_tx_irq(struct mlx4_cq *mcq);
 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb);
 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev);