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xsk: Add new statistics

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It can be useful for the user to know the reason behind a dropped packet.
Introduce new counters which track drops on the receive path caused by:
1. rx ring being full
2. fill ring being empty

Also, on the tx path introduce a counter which tracks the number of times
we attempt pull from the tx ring when it is empty.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200708072835.4427-2-ciara.loftus@intel.com
This commit is contained in:
Ciara Loftus 2020-07-08 07:28:33 +00:00 committed by Alexei Starovoitov
parent 24a38b7c0c
commit 8aa5a33578
6 changed files with 50 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/xdp_sock.h
View File

@ -69,7 +69,11 @@ struct xdp_sock {
spinlock_t tx_completion_lock;
/* Protects generic receive. */
spinlock_t rx_lock;
/* Statistics */
u64 rx_dropped;
u64 rx_queue_full;
struct list_head map_list;
/* Protects map_list */
spinlock_t map_list_lock;

5
include/uapi/linux/if_xdp.h
View File

@ -73,9 +73,12 @@ struct xdp_umem_reg {
};
struct xdp_statistics {
__u64 rx_dropped; /* Dropped for reasons other than invalid desc */
__u64 rx_dropped; /* Dropped for other reasons */
__u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
__u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
__u64 rx_ring_full; /* Dropped due to rx ring being full */
__u64 rx_fill_ring_empty_descs; /* Failed to retrieve item from fill ring */
__u64 tx_ring_empty_descs; /* Failed to retrieve item from tx ring */
};
struct xdp_options {

36
net/xdp/xsk.c
View File

@ -123,7 +123,7 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
addr = xp_get_handle(xskb);
err = xskq_prod_reserve_desc(xs->rx, addr, len);
if (err) {
xs->rx_dropped++;
xs->rx_queue_full++;
return err;
}
@ -274,8 +274,10 @@ bool xsk_umem_consume_tx(struct xdp_umem *umem, struct xdp_desc *desc)
rcu_read_lock();
list_for_each_entry_rcu(xs, &umem->xsk_tx_list, list) {
if (!xskq_cons_peek_desc(xs->tx, desc, umem))
if (!xskq_cons_peek_desc(xs->tx, desc, umem)) {
xs->tx->queue_empty_descs++;
continue;
}
/* This is the backpressure mechanism for the Tx path.
* Reserve space in the completion queue and only proceed
@ -387,6 +389,8 @@ static int xsk_generic_xmit(struct sock *sk)
sent_frame = true;
}
xs->tx->queue_empty_descs++;
out:
if (sent_frame)
sk->sk_write_space(sk);
@ -812,6 +816,12 @@ static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
ring->desc = offsetof(struct xdp_umem_ring, desc);
}
struct xdp_statistics_v1 {
__u64 rx_dropped;
__u64 rx_invalid_descs;
__u64 tx_invalid_descs;
};
static int xsk_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
@ -831,19 +841,35 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
case XDP_STATISTICS:
{
struct xdp_statistics stats;
bool extra_stats = true;
size_t stats_size;
if (len < sizeof(stats))
if (len < sizeof(struct xdp_statistics_v1)) {
return -EINVAL;
} else if (len < sizeof(stats)) {
extra_stats = false;
stats_size = sizeof(struct xdp_statistics_v1);
} else {
stats_size = sizeof(stats);
}
mutex_lock(&xs->mutex);
stats.rx_dropped = xs->rx_dropped;
if (extra_stats) {
stats.rx_ring_full = xs->rx_queue_full;
stats.rx_fill_ring_empty_descs =
xs->umem ? xskq_nb_queue_empty_descs(xs->umem->fq) : 0;
stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
} else {
stats.rx_dropped += xs->rx_queue_full;
}
stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
mutex_unlock(&xs->mutex);
if (copy_to_user(optval, &stats, sizeof(stats)))
if (copy_to_user(optval, &stats, stats_size))
return -EFAULT;
if (put_user(sizeof(stats), optlen))
if (put_user(stats_size, optlen))
return -EFAULT;
return 0;

1
net/xdp/xsk_buff_pool.c
View File

@ -235,6 +235,7 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
for (;;) {
if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
pool->fq->queue_empty_descs++;
xp_release(xskb);
return NULL;
}

6
net/xdp/xsk_queue.h
View File

@ -38,6 +38,7 @@ struct xsk_queue {
u32 cached_cons;
struct xdp_ring *ring;
u64 invalid_descs;
u64 queue_empty_descs;
};
/* The structure of the shared state of the rings are the same as the
@ -354,6 +355,11 @@ static inline u64 xskq_nb_invalid_descs(struct xsk_queue *q)
return q ? q->invalid_descs : 0;
}
static inline u64 xskq_nb_queue_empty_descs(struct xsk_queue *q)
{
return q ? q->queue_empty_descs : 0;
}
struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);
void xskq_destroy(struct xsk_queue *q_ops);

5
tools/include/uapi/linux/if_xdp.h
View File

@ -73,9 +73,12 @@ struct xdp_umem_reg {
};
struct xdp_statistics {
__u64 rx_dropped; /* Dropped for reasons other than invalid desc */
__u64 rx_dropped; /* Dropped for other reasons */
__u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
__u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
__u64 rx_ring_full; /* Dropped due to rx ring being full */
__u64 rx_fill_ring_empty_descs; /* Failed to retrieve item from fill ring */
__u64 tx_ring_empty_descs; /* Failed to retrieve item from tx ring */
};
struct xdp_options {