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authorEric Dumazet <eric.dumazet@gmail.com>2010-06-14 05:59:22 +0000
committerDavid S. Miller <davem@davemloft.net>2010-06-14 23:13:07 -0700
commit6b10de38f0ef4e921a1f6e5cba2b6c92d6b46ecd (patch)
tree76e914c5097cb80cf65bf9ce1e48acff8e46795c /drivers/net/loopback.c
parentipv6: RCU changes in ipv6_get_mtu() and ip6_dst_hoplimit() (diff)
downloadlinux-dev-6b10de38f0ef4e921a1f6e5cba2b6c92d6b46ecd.tar.xz
linux-dev-6b10de38f0ef4e921a1f6e5cba2b6c92d6b46ecd.zip
loopback: Implement 64bit stats on 32bit arches
Uses a seqcount_t to synchronize stat producer and consumer, for packets and bytes counter, now u64 types. (dropped counter being rarely used, stay a native "unsigned long" type) No noticeable performance impact on x86, as it only adds two increments per frame. It might be more expensive on arches where smp_wmb() is not free. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/loopback.c')
-rw-r--r--drivers/net/loopback.c61
1 files changed, 51 insertions, 10 deletions
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 72b7949c91b1..09334f8f148b 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -60,11 +60,51 @@
#include <net/net_namespace.h>
struct pcpu_lstats {
- unsigned long packets;
- unsigned long bytes;
+ u64 packets;
+ u64 bytes;
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+ seqcount_t seq;
+#endif
unsigned long drops;
};
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+static void inline lstats_update_begin(struct pcpu_lstats *lstats)
+{
+ write_seqcount_begin(&lstats->seq);
+}
+static void inline lstats_update_end(struct pcpu_lstats *lstats)
+{
+ write_seqcount_end(&lstats->seq);
+}
+static void inline lstats_fetch_and_add(u64 *packets, u64 *bytes, const struct pcpu_lstats *lstats)
+{
+ u64 tpackets, tbytes;
+ unsigned int seq;
+
+ do {
+ seq = read_seqcount_begin(&lstats->seq);
+ tpackets = lstats->packets;
+ tbytes = lstats->bytes;
+ } while (read_seqcount_retry(&lstats->seq, seq));
+
+ *packets += tpackets;
+ *bytes += tbytes;
+}
+#else
+static void inline lstats_update_begin(struct pcpu_lstats *lstats)
+{
+}
+static void inline lstats_update_end(struct pcpu_lstats *lstats)
+{
+}
+static void inline lstats_fetch_and_add(u64 *packets, u64 *bytes, const struct pcpu_lstats *lstats)
+{
+ *packets += lstats->packets;
+ *bytes += lstats->bytes;
+}
+#endif
+
/*
* The higher levels take care of making this non-reentrant (it's
* called with bh's disabled).
@@ -86,21 +126,23 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb,
len = skb->len;
if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
+ lstats_update_begin(lb_stats);
lb_stats->bytes += len;
lb_stats->packets++;
+ lstats_update_end(lb_stats);
} else
lb_stats->drops++;
return NETDEV_TX_OK;
}
-static struct net_device_stats *loopback_get_stats(struct net_device *dev)
+static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev)
{
const struct pcpu_lstats __percpu *pcpu_lstats;
- struct net_device_stats *stats = &dev->stats;
- unsigned long bytes = 0;
- unsigned long packets = 0;
- unsigned long drops = 0;
+ struct rtnl_link_stats64 *stats = &dev->stats64;
+ u64 bytes = 0;
+ u64 packets = 0;
+ u64 drops = 0;
int i;
pcpu_lstats = (void __percpu __force *)dev->ml_priv;
@@ -108,8 +150,7 @@ static struct net_device_stats *loopback_get_stats(struct net_device *dev)
const struct pcpu_lstats *lb_stats;
lb_stats = per_cpu_ptr(pcpu_lstats, i);
- bytes += lb_stats->bytes;
- packets += lb_stats->packets;
+ lstats_fetch_and_add(&packets, &bytes, lb_stats);
drops += lb_stats->drops;
}
stats->rx_packets = packets;
@@ -158,7 +199,7 @@ static void loopback_dev_free(struct net_device *dev)
static const struct net_device_ops loopback_ops = {
.ndo_init = loopback_dev_init,
.ndo_start_xmit= loopback_xmit,
- .ndo_get_stats = loopback_get_stats,
+ .ndo_get_stats64 = loopback_get_stats64,
};
/*