| Message ID | 20110609005417.449670103@vyatta.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 2011-06-08 at 17:53 -0700, Stephen Hemminger wrote: > Not much change, device was already keeping per cpu statistics. > Use recent 64 statistics interface. [...] It's also going to need to use u64_stats_sync functions. Ben.
On Thu, 09 Jun 2011 03:00:41 +0100 Ben Hutchings <bhutchings@solarflare.com> wrote: > On Wed, 2011-06-08 at 17:53 -0700, Stephen Hemminger wrote: > > Not much change, device was already keeping per cpu statistics. > > Use recent 64 statistics interface. > [...] > > It's also going to need to use u64_stats_sync functions. > > Ben. > No veth is doing per-cpu update therefore the new code has the same guarantee as the old code. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Stephen Hemminger <shemminger@vyatta.com> Date: Wed, 08 Jun 2011 17:53:59 -0700 > Not much change, device was already keeping per cpu statistics. > Use recent 64 statistics interface. > > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2011-06-08 at 20:22 -0700, Stephen Hemminger wrote: > On Thu, 09 Jun 2011 03:00:41 +0100 > Ben Hutchings <bhutchings@solarflare.com> wrote: > > > On Wed, 2011-06-08 at 17:53 -0700, Stephen Hemminger wrote: > > > Not much change, device was already keeping per cpu statistics. > > > Use recent 64 statistics interface. > > [...] > > > > It's also going to need to use u64_stats_sync functions. > > > > Ben. > > > > No veth is doing per-cpu update therefore the new code has the same guarantee > as the old code. Per-cpu statistics avoid the problem of races between writers without using expensive atomic operations. They don't solve the problem of races between writer and reader (on 32-bit systems). For example, if veth_get_stats() races with a receive or transmit that increments a value from 0x00000001ffffffff to 0x0000000200000000, it may see the value as 0x00000002ffffffff. Ben.
--- a/drivers/net/veth.c 2011-06-07 20:04:42.221679879 +0900 +++ b/drivers/net/veth.c 2011-06-07 20:10:04.259276778 +0900 @@ -24,12 +24,12 @@ #define MAX_MTU 65535 /* Max L3 MTU (arbitrary) */ struct veth_net_stats { - unsigned long rx_packets; - unsigned long tx_packets; - unsigned long rx_bytes; - unsigned long tx_bytes; - unsigned long tx_dropped; - unsigned long rx_dropped; + u64 rx_packets; + u64 tx_packets; + u64 rx_bytes; + u64 tx_bytes; + u64 tx_dropped; + u64 rx_dropped; }; struct veth_priv { @@ -159,32 +159,27 @@ rx_drop: * general routines */ -static struct net_device_stats *veth_get_stats(struct net_device *dev) +static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev, + struct rtnl_link_stats64 *tot) { struct veth_priv *priv; int cpu; - struct veth_net_stats *stats, total = {0}; + struct veth_net_stats *stats; priv = netdev_priv(dev); for_each_possible_cpu(cpu) { stats = per_cpu_ptr(priv->stats, cpu); - total.rx_packets += stats->rx_packets; - total.tx_packets += stats->tx_packets; - total.rx_bytes += stats->rx_bytes; - total.tx_bytes += stats->tx_bytes; - total.tx_dropped += stats->tx_dropped; - total.rx_dropped += stats->rx_dropped; + tot->rx_packets += stats->rx_packets; + tot->tx_packets += stats->tx_packets; + tot->rx_bytes += stats->rx_bytes; + tot->tx_bytes += stats->tx_bytes; + tot->tx_dropped += stats->tx_dropped; + tot->rx_dropped += stats->rx_dropped; } - dev->stats.rx_packets = total.rx_packets; - dev->stats.tx_packets = total.tx_packets; - dev->stats.rx_bytes = total.rx_bytes; - dev->stats.tx_bytes = total.tx_bytes; - dev->stats.tx_dropped = total.tx_dropped; - dev->stats.rx_dropped = total.rx_dropped; - return &dev->stats; + return tot; } static int veth_open(struct net_device *dev) @@ -254,7 +249,7 @@ static const struct net_device_ops veth_ .ndo_stop = veth_close, .ndo_start_xmit = veth_xmit, .ndo_change_mtu = veth_change_mtu, - .ndo_get_stats = veth_get_stats, + .ndo_get_stats64 = veth_get_stats64, .ndo_set_mac_address = eth_mac_addr, };
Not much change, device was already keeping per cpu statistics. Use recent 64 statistics interface. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html