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Commit 53511453 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarJim Davis <jim.epost@gmail.com>
Fixes: 29d40c90 ("net/mlx4_en: Use prefetch in tx path")
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 709c48b3

drivers/net/ethernet/mellanox/mlx4/en_tx.c

+3 −2
Original line number Diff line number Diff line
@@ -392,7 +392,8 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, 
	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 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) 
		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,

include/linux/netdevice.h

+29 −0
Original line number Diff line number Diff line
@@ -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 @@ netif_xmit_frozen_or_drv_stopped(const struct netdev_queue *dev_queue) 
	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)

{