Convert xen driver to 64 bit statistics interface.
Use stats_sync to ensure that 64 bit update is read atomically on 32 bit
platform.
Put hot statistics into per-cpu table.
Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>
---
v2 - add stats_sync and per-cpu
v2.1 - keep rx_errors on checksum error
--- a/drivers/net/xen-netfront.c 2011-06-20 14:50:01.271989938 -0700
+++ b/drivers/net/xen-netfront.c 2011-06-21 08:33:12.851953760 -0700
@@ -70,6 +70,14 @@ struct netfront_cb {
#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+struct netfront_stats {
+ u64 rx_packets;
+ u64 tx_packets;
+ u64 rx_bytes;
+ u64 tx_bytes;
+ struct u64_stats_sync syncp;
+};
+
struct netfront_info {
struct list_head list;
struct net_device *netdev;
@@ -122,6 +130,8 @@ struct netfront_info {
struct mmu_update rx_mmu[NET_RX_RING_SIZE];
/* Statistics */
+ struct netfront_stats __percpu *stats;
+
unsigned long rx_gso_checksum_fixup;
};
@@ -468,6 +478,7 @@ static int xennet_start_xmit(struct sk_b
{
unsigned short id;
struct netfront_info *np = netdev_priv(dev);
+ struct netfront_stats *stats = this_cpu_ptr(np->stats);
struct xen_netif_tx_request *tx;
struct xen_netif_extra_info *extra;
char *data = skb->data;
@@ -552,8 +563,10 @@ static int xennet_start_xmit(struct sk_b
if (notify)
notify_remote_via_irq(np->netdev->irq);
- dev->stats.tx_bytes += skb->len;
- dev->stats.tx_packets++;
+ u64_stats_update_begin(&stats->syncp);
+ stats->tx_bytes += skb->len;
+ stats->tx_packets++;
+ u64_stats_update_end(&stats->syncp);
/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
xennet_tx_buf_gc(dev);
@@ -847,6 +860,8 @@ out:
static int handle_incoming_queue(struct net_device *dev,
struct sk_buff_head *rxq)
{
+ struct netfront_info *np = netdev_priv(dev);
+ struct netfront_stats *stats = this_cpu_ptr(np->stats);
int packets_dropped = 0;
struct sk_buff *skb;
@@ -871,8 +886,10 @@ static int handle_incoming_queue(struct
continue;
}
- dev->stats.rx_packets++;
- dev->stats.rx_bytes += skb->len;
+ u64_stats_update_begin(&stats->syncp);
+ stats->rx_packets++;
+ stats->rx_bytes += skb->len;
+ u64_stats_update_end(&stats->syncp);
/* Pass it up. */
netif_receive_skb(skb);
@@ -1034,6 +1051,38 @@ static int xennet_change_mtu(struct net_
return 0;
}
+static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
+ struct rtnl_link_stats64
*tot)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
+ u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
+ unsigned int start;
+
+ do {
+ start = u64_stats_fetch_begin_bh(&stats->syncp);
+
+ rx_packets = stats->rx_packets;
+ tx_packets = stats->tx_packets;
+ rx_bytes = stats->rx_bytes;
+ tx_bytes = stats->tx_bytes;
+ } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
+
+ tot->rx_packets += rx_packets;
+ tot->tx_packets += tx_packets;
+ tot->rx_bytes += rx_bytes;
+ tot->tx_bytes += tx_bytes;
+ }
+
+ tot->rx_errors = dev->stats.rx_errors;
+ tot->tx_dropped = dev->stats.tx_dropped;
+
+ return tot;
+}
+
static void xennet_release_tx_bufs(struct netfront_info *np)
{
struct sk_buff *skb;
@@ -1182,6 +1231,7 @@ static const struct net_device_ops xenne
.ndo_stop = xennet_close,
.ndo_start_xmit = xennet_start_xmit,
.ndo_change_mtu = xennet_change_mtu,
+ .ndo_get_stats64 = xennet_get_stats64,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
.ndo_fix_features = xennet_fix_features,
@@ -1216,6 +1266,11 @@ static struct net_device * __devinit xen
np->rx_refill_timer.data = (unsigned long)netdev;
np->rx_refill_timer.function = rx_refill_timeout;
+ err = -ENOMEM;
+ np->stats = alloc_percpu(struct netfront_stats);
+ if (np->stats == NULL)
+ goto exit;
+
/* Initialise tx_skbs as a free chain containing every entry. */
np->tx_skb_freelist = 0;
for (i = 0; i < NET_TX_RING_SIZE; i++) {
@@ -1234,7 +1289,7 @@ static struct net_device * __devinit xen
&np->gref_tx_head) < 0) {
printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
err = -ENOMEM;
- goto exit;
+ goto exit_free_stats;
}
/* A grant for every rx ring slot */
if (gnttab_alloc_grant_references(RX_MAX_TARGET,
@@ -1270,6 +1325,8 @@ static struct net_device * __devinit xen
exit_free_tx:
gnttab_free_grant_references(np->gref_tx_head);
+ exit_free_stats:
+ free_percpu(np->stats);
exit:
free_netdev(netdev);
return ERR_PTR(err);
@@ -1869,6 +1926,8 @@ static int __devexit xennet_remove(struc
xennet_sysfs_delif(info->netdev);
+ free_percpu(info->stats);
+
free_netdev(info->netdev);
return 0;
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