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sunvnet: Use one Tx queue per vnet_port
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Use multple Tx netdev queues for sunvnet by supporting a one-to-one
mapping between vnet_port and Tx queue. Provide a ndo_select_queue
indirection (vnet_select_queue()) which selects the queue based
on the peer that would be selected in vnet_start_xmit()

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Sowmini Varadhan authored and David S. Miller committed Oct 30, 2014
1 parent 7bd68bf commit d51bffd
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Showing 2 changed files with 65 additions and 31 deletions.
94 changes: 63 additions & 31 deletions drivers/net/ethernet/sun/sunvnet.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,8 @@ MODULE_DESCRIPTION("Sun LDOM virtual network driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_MODULE_VERSION);

#define VNET_MAX_TXQS 16

/* Heuristic for the number of times to exponentially backoff and
* retry sending an LDC trigger when EAGAIN is encountered
*/
Expand Down Expand Up @@ -551,6 +553,8 @@ static int vnet_ack(struct vnet_port *port, void *msgbuf)
struct vnet *vp;
u32 end;
struct vio_net_desc *desc;
struct netdev_queue *txq;

if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
return 0;

Expand Down Expand Up @@ -580,7 +584,8 @@ static int vnet_ack(struct vnet_port *port, void *msgbuf)
}
netif_tx_unlock(dev);

if (unlikely(netif_queue_stopped(dev) &&
txq = netdev_get_tx_queue(dev, port->q_index);
if (unlikely(netif_tx_queue_stopped(txq) &&
vnet_tx_dring_avail(dr) >= VNET_TX_WAKEUP_THRESH(dr)))
return 1;

Expand Down Expand Up @@ -608,31 +613,23 @@ static int handle_mcast(struct vnet_port *port, void *msgbuf)
return 0;
}

static void maybe_tx_wakeup(struct vnet *vp)
/* Got back a STOPPED LDC message on port. If the queue is stopped,
* wake it up so that we'll send out another START message at the
* next TX.
*/
static void maybe_tx_wakeup(struct vnet_port *port)
{
struct net_device *dev = vp->dev;
struct netdev_queue *txq;

netif_tx_lock(dev);
if (likely(netif_queue_stopped(dev))) {
struct vnet_port *port;
int wake = 1;

rcu_read_lock();
list_for_each_entry_rcu(port, &vp->port_list, list) {
struct vio_dring_state *dr;

dr = &port->vio.drings[VIO_DRIVER_TX_RING];
if (vnet_tx_dring_avail(dr) <
VNET_TX_WAKEUP_THRESH(dr)) {
wake = 0;
break;
}
}
rcu_read_unlock();
if (wake)
netif_wake_queue(dev);
txq = netdev_get_tx_queue(port->vp->dev, port->q_index);
__netif_tx_lock(txq, smp_processor_id());
if (likely(netif_tx_queue_stopped(txq))) {
struct vio_dring_state *dr;

dr = &port->vio.drings[VIO_DRIVER_TX_RING];
netif_tx_wake_queue(txq);
}
netif_tx_unlock(dev);
__netif_tx_unlock(txq);
}

static inline bool port_is_up(struct vnet_port *vnet)
Expand Down Expand Up @@ -748,7 +745,7 @@ static int vnet_event_napi(struct vnet_port *port, int budget)
break;
}
if (unlikely(tx_wakeup && err != -ECONNRESET))
maybe_tx_wakeup(port->vp);
maybe_tx_wakeup(port);
return npkts;
}

Expand Down Expand Up @@ -953,6 +950,16 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
return skb;
}

static u16
vnet_select_queue(struct net_device *dev, struct sk_buff *skb,
void *accel_priv, select_queue_fallback_t fallback)
{
struct vnet *vp = netdev_priv(dev);
struct vnet_port *port = __tx_port_find(vp, skb);

return port->q_index;
}

static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct vnet *vp = netdev_priv(dev);
Expand All @@ -965,6 +972,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
void *start = NULL;
int nlen = 0;
unsigned pending = 0;
struct netdev_queue *txq;

skb = vnet_skb_shape(skb, &start, &nlen);
if (unlikely(!skb))
Expand Down Expand Up @@ -1008,9 +1016,11 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
}

dr = &port->vio.drings[VIO_DRIVER_TX_RING];
i = skb_get_queue_mapping(skb);
txq = netdev_get_tx_queue(dev, i);
if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
if (!netif_queue_stopped(dev)) {
netif_stop_queue(dev);
if (!netif_tx_queue_stopped(txq)) {
netif_tx_stop_queue(txq);

/* This is a hard error, log it. */
netdev_err(dev, "BUG! Tx Ring full when queue awake!\n");
Expand Down Expand Up @@ -1104,9 +1114,9 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)

dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
netif_stop_queue(dev);
netif_tx_stop_queue(txq);
if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
netif_wake_queue(dev);
netif_tx_wake_queue(txq);
}

(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);
Expand Down Expand Up @@ -1139,14 +1149,14 @@ static void vnet_tx_timeout(struct net_device *dev)
static int vnet_open(struct net_device *dev)
{
netif_carrier_on(dev);
netif_start_queue(dev);
netif_tx_start_all_queues(dev);

return 0;
}

static int vnet_close(struct net_device *dev)
{
netif_stop_queue(dev);
netif_tx_stop_all_queues(dev);
netif_carrier_off(dev);

return 0;
Expand Down Expand Up @@ -1420,6 +1430,7 @@ static const struct net_device_ops vnet_ops = {
.ndo_tx_timeout = vnet_tx_timeout,
.ndo_change_mtu = vnet_change_mtu,
.ndo_start_xmit = vnet_start_xmit,
.ndo_select_queue = vnet_select_queue,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = vnet_poll_controller,
#endif
Expand All @@ -1431,7 +1442,7 @@ static struct vnet *vnet_new(const u64 *local_mac)
struct vnet *vp;
int err, i;

dev = alloc_etherdev(sizeof(*vp));
dev = alloc_etherdev_mqs(sizeof(*vp), VNET_MAX_TXQS, 1);
if (!dev)
return ERR_PTR(-ENOMEM);
dev->needed_headroom = VNET_PACKET_SKIP + 8;
Expand Down Expand Up @@ -1556,6 +1567,25 @@ static void print_version(void)

const char *remote_macaddr_prop = "remote-mac-address";

static void
vnet_port_add_txq(struct vnet_port *port)
{
struct vnet *vp = port->vp;
int n;

n = vp->nports++;
n = n & (VNET_MAX_TXQS - 1);
port->q_index = n;
netif_tx_wake_queue(netdev_get_tx_queue(vp->dev, port->q_index));
}

static void
vnet_port_rm_txq(struct vnet_port *port)
{
port->vp->nports--;
netif_tx_stop_queue(netdev_get_tx_queue(port->vp->dev, port->q_index));
}

static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
{
struct mdesc_handle *hp;
Expand Down Expand Up @@ -1624,6 +1654,7 @@ static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
list_add_tail_rcu(&port->list, &vp->port_list);
hlist_add_head_rcu(&port->hash,
&vp->port_hash[vnet_hashfn(port->raddr)]);
vnet_port_add_txq(port);
spin_unlock_irqrestore(&vp->lock, flags);

dev_set_drvdata(&vdev->dev, port);
Expand Down Expand Up @@ -1668,6 +1699,7 @@ static int vnet_port_remove(struct vio_dev *vdev)

synchronize_rcu();
del_timer_sync(&port->clean_timer);
vnet_port_rm_txq(port);
netif_napi_del(&port->napi);
vnet_port_free_tx_bufs(port);
vio_ldc_free(&port->vio);
Expand Down
2 changes: 2 additions & 0 deletions drivers/net/ethernet/sun/sunvnet.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,7 @@ struct vnet_port {
u32 napi_stop_idx;
bool napi_resume;
int rx_event;
u16 q_index;
};

static inline struct vnet_port *to_vnet_port(struct vio_driver_state *vio)
Expand Down Expand Up @@ -102,6 +103,7 @@ struct vnet {
struct list_head list;
u64 local_mac;

int nports;
};

#endif /* _SUNVNET_H */

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