net: add netdev_txq_bql_{enqueue, complete}_prefetchw() helpers
Add two helpers so that drivers do not have to care of BQL being
available or not.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jim Davis <jim.epost@gmail.com>
Fixes: 29d40c903247 ("net/mlx4_en: Use prefetch in tx path")
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 8726a4a..34c1378 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -392,7 +392,8 @@
if (!priv->port_up)
return true;
- prefetchw(&ring->tx_queue->dql.limit);
+ netdev_txq_bql_complete_prefetchw(ring->tx_queue);
+
index = cons_index & size_mask;
cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
last_nr_txbb = ACCESS_ONCE(ring->last_nr_txbb);
@@ -737,7 +738,7 @@
vlan_tag = vlan_tx_tag_get(skb);
- prefetchw(&ring->tx_queue->dql);
+ netdev_txq_bql_enqueue_prefetchw(ring->tx_queue);
/* Track current inflight packets for performance analysis */
AVG_PERF_COUNTER(priv->pstats.inflight_avg,
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3a4315b..838407a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -30,6 +30,7 @@
#include <linux/bug.h>
#include <linux/delay.h>
#include <linux/atomic.h>
+#include <linux/prefetch.h>
#include <asm/cache.h>
#include <asm/byteorder.h>
@@ -2480,6 +2481,34 @@
return dev_queue->state & QUEUE_STATE_DRV_XOFF_OR_FROZEN;
}
+/**
+ * netdev_txq_bql_enqueue_prefetchw - prefetch bql data for write
+ * @dev_queue: pointer to transmit queue
+ *
+ * BQL enabled drivers might use this helper in their ndo_start_xmit(),
+ * to give appropriate hint to the cpu.
+ */
+static inline void netdev_txq_bql_enqueue_prefetchw(struct netdev_queue *dev_queue)
+{
+#ifdef CONFIG_BQL
+ prefetchw(&dev_queue->dql.num_queued);
+#endif
+}
+
+/**
+ * netdev_txq_bql_complete_prefetchw - prefetch bql data for write
+ * @dev_queue: pointer to transmit queue
+ *
+ * BQL enabled drivers might use this helper in their TX completion path,
+ * to give appropriate hint to the cpu.
+ */
+static inline void netdev_txq_bql_complete_prefetchw(struct netdev_queue *dev_queue)
+{
+#ifdef CONFIG_BQL
+ prefetchw(&dev_queue->dql.limit);
+#endif
+}
+
static inline void netdev_tx_sent_queue(struct netdev_queue *dev_queue,
unsigned int bytes)
{