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hv_netvsc: use per_cpu stats to calculate TX/RX data

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Current code does not lock anything when calculating the TX and RX stats.
As a result, the RX and TX data reported by ifconfig are not accuracy in a
system with high network throughput and multiple CPUs (in my test,
RX/TX = 83% between 2 HyperV VM nodes which have 8 vCPUs and 40G Ethernet).

This patch fixed the above issue by using per_cpu stats.
netvsc_get_stats64() summarizes TX and RX data by iterating over all CPUs
to get their respective stats.

This v2 patch addressed David's comments on the cleanup path when
netdev_alloc_pcpu_stats() failed.

Signed-off-by: Simon Xiao <sixiao@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
sixiao@microsoft.com 2015-05-14 01:00:25 -07:00 committed by David S. Miller
parent 56cbaa45dd
commit 7eafd9b400
2 changed files with 86 additions and 8 deletions
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9
drivers/net/hyperv/hyperv_net.h
View File

@ -611,6 +611,12 @@ struct multi_send_data {
u32 count; /* counter of batched packets */
};
struct netvsc_stats {
u64 packets;
u64 bytes;
struct u64_stats_sync s_sync;
};
/* The context of the netvsc device */
struct net_device_context {
/* point back to our device context */
@ -618,6 +624,9 @@ struct net_device_context {
struct delayed_work dwork;
struct work_struct work;
u32 msg_enable; /* debug level */
struct netvsc_stats __percpu *tx_stats;
struct netvsc_stats __percpu *rx_stats;
};
/* Per netvsc device */

85
drivers/net/hyperv/netvsc_drv.c
View File

@ -391,7 +391,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
u32 skb_length;
u32 pkt_sz;
struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
/* We will atmost need two pages to describe the rndis
* header. We can only transmit MAX_PAGE_BUFFER_COUNT number
@ -580,8 +580,10 @@ do_send:
drop:
if (ret == 0) {
net->stats.tx_bytes += skb_length;
net->stats.tx_packets++;
u64_stats_update_begin(&tx_stats->s_sync);
tx_stats->packets++;
tx_stats->bytes += skb_length;
u64_stats_update_end(&tx_stats->s_sync);
} else {
if (ret != -EAGAIN) {
dev_kfree_skb_any(skb);
@ -644,13 +646,17 @@ int netvsc_recv_callback(struct hv_device *device_obj,
struct ndis_tcp_ip_checksum_info *csum_info)
{
struct net_device *net;
struct net_device_context *net_device_ctx;
struct sk_buff *skb;
struct netvsc_stats *rx_stats;
net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
if (!net || net->reg_state != NETREG_REGISTERED) {
packet->status = NVSP_STAT_FAIL;
return 0;
}
net_device_ctx = netdev_priv(net);
rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);
/* Allocate a skb - TODO direct I/O to pages? */
skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
@ -686,8 +692,10 @@ int netvsc_recv_callback(struct hv_device *device_obj,
skb_record_rx_queue(skb, packet->channel->
offermsg.offer.sub_channel_index);
net->stats.rx_packets++;
net->stats.rx_bytes += packet->total_data_buflen;
u64_stats_update_begin(&rx_stats->s_sync);
rx_stats->packets++;
rx_stats->bytes += packet->total_data_buflen;
u64_stats_update_end(&rx_stats->s_sync);
/*
* Pass the skb back up. Network stack will deallocate the skb when it
@ -753,6 +761,46 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
return 0;
}
static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
struct rtnl_link_stats64 *t)
{
struct net_device_context *ndev_ctx = netdev_priv(net);
int cpu;
for_each_possible_cpu(cpu) {
struct netvsc_stats *tx_stats = per_cpu_ptr(ndev_ctx->tx_stats,
cpu);
struct netvsc_stats *rx_stats = per_cpu_ptr(ndev_ctx->rx_stats,
cpu);
u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
unsigned int start;
do {
start = u64_stats_fetch_begin_irq(&tx_stats->s_sync);
tx_packets = tx_stats->packets;
tx_bytes = tx_stats->bytes;
} while (u64_stats_fetch_retry_irq(&tx_stats->s_sync, start));
do {
start = u64_stats_fetch_begin_irq(&rx_stats->s_sync);
rx_packets = rx_stats->packets;
rx_bytes = rx_stats->bytes;
} while (u64_stats_fetch_retry_irq(&rx_stats->s_sync, start));
t->tx_bytes += tx_bytes;
t->tx_packets += tx_packets;
t->rx_bytes += rx_bytes;
t->rx_packets += rx_packets;
}
t->tx_dropped = net->stats.tx_dropped;
t->tx_errors = net->stats.tx_dropped;
t->rx_dropped = net->stats.rx_dropped;
t->rx_errors = net->stats.rx_errors;
return t;
}
static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
{
@ -804,6 +852,7 @@ static const struct net_device_ops device_ops = {
.ndo_validate_addr = eth_validate_addr,
.ndo_set_mac_address = netvsc_set_mac_addr,
.ndo_select_queue = netvsc_select_queue,
.ndo_get_stats64 = netvsc_get_stats64,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = netvsc_poll_controller,
#endif
@ -855,6 +904,14 @@ static void netvsc_link_change(struct work_struct *w)
netdev_notify_peers(net);
}
static void netvsc_free_netdev(struct net_device *netdev)
{
struct net_device_context *net_device_ctx = netdev_priv(netdev);
free_percpu(net_device_ctx->tx_stats);
free_percpu(net_device_ctx->rx_stats);
free_netdev(netdev);
}
static int netvsc_probe(struct hv_device *dev,
const struct hv_vmbus_device_id *dev_id)
@ -883,6 +940,18 @@ static int netvsc_probe(struct hv_device *dev,
netdev_dbg(net, "netvsc msg_enable: %d\n",
net_device_ctx->msg_enable);
net_device_ctx->tx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
if (!net_device_ctx->tx_stats) {
free_netdev(net);
return -ENOMEM;
}
net_device_ctx->rx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
if (!net_device_ctx->rx_stats) {
free_percpu(net_device_ctx->tx_stats);
free_netdev(net);
return -ENOMEM;
}
hv_set_drvdata(dev, net);
INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
INIT_WORK(&net_device_ctx->work, do_set_multicast);
@ -909,7 +978,7 @@ static int netvsc_probe(struct hv_device *dev,
ret = rndis_filter_device_add(dev, &device_info);
if (ret != 0) {
netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
free_netdev(net);
netvsc_free_netdev(net);
hv_set_drvdata(dev, NULL);
return ret;
}
@ -923,7 +992,7 @@ static int netvsc_probe(struct hv_device *dev,
if (ret != 0) {
pr_err("Unable to register netdev.\n");
rndis_filter_device_remove(dev);
free_netdev(net);
netvsc_free_netdev(net);
} else {
schedule_delayed_work(&net_device_ctx->dwork, 0);
}
@ -962,7 +1031,7 @@ static int netvsc_remove(struct hv_device *dev)
*/
rndis_filter_device_remove(dev);
free_netdev(net);
netvsc_free_netdev(net);
return 0;
}