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Merge branch 'veth-XDP-stats-improvement'
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Toshiaki Makita says:

====================
veth: XDP stats improvement

ndo_xdp_xmit in veth did not update packet counters as described in [1].
Also, current implementation only updates counters on tx side so rx side
events like XDP_DROP were not collected.
This series implements the missing accounting as well as support for
ethtool per-queue stats in veth.

Patch 1: Update drop counter in ndo_xdp_xmit.
Patch 2: Update packet and byte counters for all XDP path, and drop
         counter on XDP_DROP.
Patch 3: Support per-queue ethtool stats for XDP counters.

Note that counters are maintained on per-queue basis for XDP but not
otherwise (per-cpu and atomic as before). This is because 1) tx path in
veth is essentially lockless so we cannot update per-queue stats on tx,
and 2) rx path is net core routine (process_backlog) which cannot update
per-queue based stats when XDP is disabled. On the other hand there are
real rxqs and napi handlers for veth XDP, so update per-queue stats on
rx for XDP packets, and use them to calculate tx counters as well,
contrary to the existing non-XDP counters.

[1] https://patchwork.ozlabs.org/cover/953071/#1967449
====================

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Oct 16, 2018
2 parents acad76a + d397b96 commit a75d180
Showing 1 changed file with 147 additions and 28 deletions.
175 changes: 147 additions & 28 deletions drivers/net/veth.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,19 @@
#define VETH_XDP_TX BIT(0)
#define VETH_XDP_REDIR BIT(1)

struct veth_rq_stats {
u64 xdp_packets;
u64 xdp_bytes;
u64 xdp_drops;
struct u64_stats_sync syncp;
};

struct veth_rq {
struct napi_struct xdp_napi;
struct net_device *dev;
struct bpf_prog __rcu *xdp_prog;
struct xdp_mem_info xdp_mem;
struct veth_rq_stats stats;
bool rx_notify_masked;
struct ptr_ring xdp_ring;
struct xdp_rxq_info xdp_rxq;
Expand All @@ -59,6 +67,21 @@ struct veth_priv {
* ethtool interface
*/

struct veth_q_stat_desc {
char desc[ETH_GSTRING_LEN];
size_t offset;
};

#define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)

static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
{ "xdp_packets", VETH_RQ_STAT(xdp_packets) },
{ "xdp_bytes", VETH_RQ_STAT(xdp_bytes) },
{ "xdp_drops", VETH_RQ_STAT(xdp_drops) },
};

#define VETH_RQ_STATS_LEN ARRAY_SIZE(veth_rq_stats_desc)

static struct {
const char string[ETH_GSTRING_LEN];
} ethtool_stats_keys[] = {
Expand All @@ -83,9 +106,20 @@ static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *inf

static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
{
char *p = (char *)buf;
int i, j;

switch(stringset) {
case ETH_SS_STATS:
memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
p += sizeof(ethtool_stats_keys);
for (i = 0; i < dev->real_num_rx_queues; i++) {
for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
snprintf(p, ETH_GSTRING_LEN, "rx_queue_%u_%s",
i, veth_rq_stats_desc[j].desc);
p += ETH_GSTRING_LEN;
}
}
break;
}
}
Expand All @@ -94,7 +128,8 @@ static int veth_get_sset_count(struct net_device *dev, int sset)
{
switch (sset) {
case ETH_SS_STATS:
return ARRAY_SIZE(ethtool_stats_keys);
return ARRAY_SIZE(ethtool_stats_keys) +
VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
default:
return -EOPNOTSUPP;
}
Expand All @@ -105,8 +140,25 @@ static void veth_get_ethtool_stats(struct net_device *dev,
{
struct veth_priv *priv = netdev_priv(dev);
struct net_device *peer = rtnl_dereference(priv->peer);
int i, j, idx;

data[0] = peer ? peer->ifindex : 0;
idx = 1;
for (i = 0; i < dev->real_num_rx_queues; i++) {
const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
const void *stats_base = (void *)rq_stats;
unsigned int start;
size_t offset;

do {
start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
offset = veth_rq_stats_desc[j].offset;
data[idx + j] = *(u64 *)(stats_base + offset);
}
} while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
idx += VETH_RQ_STATS_LEN;
}
}

static int veth_get_ts_info(struct net_device *dev,
Expand Down Expand Up @@ -211,12 +263,14 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)

skb_tx_timestamp(skb);
if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
if (!rcv_xdp) {
struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);

u64_stats_update_begin(&stats->syncp);
stats->bytes += length;
stats->packets++;
u64_stats_update_end(&stats->syncp);
u64_stats_update_begin(&stats->syncp);
stats->bytes += length;
stats->packets++;
u64_stats_update_end(&stats->syncp);
}
} else {
drop:
atomic64_inc(&priv->dropped);
Expand All @@ -230,7 +284,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_OK;
}

static u64 veth_stats_one(struct pcpu_lstats *result, struct net_device *dev)
static u64 veth_stats_tx(struct pcpu_lstats *result, struct net_device *dev)
{
struct veth_priv *priv = netdev_priv(dev);
int cpu;
Expand All @@ -253,23 +307,58 @@ static u64 veth_stats_one(struct pcpu_lstats *result, struct net_device *dev)
return atomic64_read(&priv->dropped);
}

static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
{
struct veth_priv *priv = netdev_priv(dev);
int i;

result->xdp_packets = 0;
result->xdp_bytes = 0;
result->xdp_drops = 0;
for (i = 0; i < dev->num_rx_queues; i++) {
struct veth_rq_stats *stats = &priv->rq[i].stats;
u64 packets, bytes, drops;
unsigned int start;

do {
start = u64_stats_fetch_begin_irq(&stats->syncp);
packets = stats->xdp_packets;
bytes = stats->xdp_bytes;
drops = stats->xdp_drops;
} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
result->xdp_packets += packets;
result->xdp_bytes += bytes;
result->xdp_drops += drops;
}
}

static void veth_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *tot)
{
struct veth_priv *priv = netdev_priv(dev);
struct net_device *peer;
struct pcpu_lstats one;
struct veth_rq_stats rx;
struct pcpu_lstats tx;

tot->tx_dropped = veth_stats_one(&one, dev);
tot->tx_bytes = one.bytes;
tot->tx_packets = one.packets;
tot->tx_dropped = veth_stats_tx(&tx, dev);
tot->tx_bytes = tx.bytes;
tot->tx_packets = tx.packets;

veth_stats_rx(&rx, dev);
tot->rx_dropped = rx.xdp_drops;
tot->rx_bytes = rx.xdp_bytes;
tot->rx_packets = rx.xdp_packets;

rcu_read_lock();
peer = rcu_dereference(priv->peer);
if (peer) {
tot->rx_dropped = veth_stats_one(&one, peer);
tot->rx_bytes = one.bytes;
tot->rx_packets = one.packets;
tot->rx_dropped += veth_stats_tx(&tx, peer);
tot->rx_bytes += tx.bytes;
tot->rx_packets += tx.packets;

veth_stats_rx(&rx, peer);
tot->tx_bytes += rx.xdp_bytes;
tot->tx_packets += rx.xdp_packets;
}
rcu_read_unlock();
}
Expand Down Expand Up @@ -308,26 +397,33 @@ static int veth_xdp_xmit(struct net_device *dev, int n,
{
struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
struct net_device *rcv;
int i, ret, drops = n;
unsigned int max_len;
struct veth_rq *rq;
int i, drops = 0;

if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
return -EINVAL;
if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
ret = -EINVAL;
goto drop;
}

rcv = rcu_dereference(priv->peer);
if (unlikely(!rcv))
return -ENXIO;
if (unlikely(!rcv)) {
ret = -ENXIO;
goto drop;
}

rcv_priv = netdev_priv(rcv);
rq = &rcv_priv->rq[veth_select_rxq(rcv)];
/* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
* side. This means an XDP program is loaded on the peer and the peer
* device is up.
*/
if (!rcu_access_pointer(rq->xdp_prog))
return -ENXIO;
if (!rcu_access_pointer(rq->xdp_prog)) {
ret = -ENXIO;
goto drop;
}

drops = 0;
max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;

spin_lock(&rq->xdp_ring.producer_lock);
Expand All @@ -346,7 +442,14 @@ static int veth_xdp_xmit(struct net_device *dev, int n,
if (flags & XDP_XMIT_FLUSH)
__veth_xdp_flush(rq);

return n - drops;
if (likely(!drops))
return n;

ret = n - drops;
drop:
atomic64_add(drops, &priv->dropped);

return ret;
}

static void veth_xdp_flush(struct net_device *dev)
Expand Down Expand Up @@ -595,28 +698,42 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,

static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit)
{
int i, done = 0;
int i, done = 0, drops = 0, bytes = 0;

for (i = 0; i < budget; i++) {
void *ptr = __ptr_ring_consume(&rq->xdp_ring);
unsigned int xdp_xmit_one = 0;
struct sk_buff *skb;

if (!ptr)
break;

if (veth_is_xdp_frame(ptr)) {
skb = veth_xdp_rcv_one(rq, veth_ptr_to_xdp(ptr),
xdp_xmit);
struct xdp_frame *frame = veth_ptr_to_xdp(ptr);

bytes += frame->len;
skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one);
} else {
skb = veth_xdp_rcv_skb(rq, ptr, xdp_xmit);
skb = ptr;
bytes += skb->len;
skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one);
}
*xdp_xmit |= xdp_xmit_one;

if (skb)
napi_gro_receive(&rq->xdp_napi, skb);
else if (!xdp_xmit_one)
drops++;

done++;
}

u64_stats_update_begin(&rq->stats.syncp);
rq->stats.xdp_packets += done;
rq->stats.xdp_bytes += bytes;
rq->stats.xdp_drops += drops;
u64_stats_update_end(&rq->stats.syncp);

return done;
}

Expand Down Expand Up @@ -807,8 +924,10 @@ static int veth_alloc_queues(struct net_device *dev)
if (!priv->rq)
return -ENOMEM;

for (i = 0; i < dev->num_rx_queues; i++)
for (i = 0; i < dev->num_rx_queues; i++) {
priv->rq[i].dev = dev;
u64_stats_init(&priv->rq[i].stats.syncp);
}

return 0;
}
Expand Down

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