Commit 8aa5a335 authored by Ciara Loftus's avatar Ciara Loftus Committed by Alexei Starovoitov
Browse files

xsk: Add new statistics 



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: default avatarCiara Loftus <ciara.loftus@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200708072835.4427-2-ciara.loftus@intel.com
parent 24a38b7c

include/net/xdp_sock.h

+4 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/if_xdp.h

+4 −1
Original line number Diff line number Diff line
@@ -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 {

net/xdp/xsk.c

+31 −5
Original line number Diff line number Diff line
@@ -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;

net/xdp/xsk_buff_pool.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

		}

net/xdp/xsk_queue.h

+6 −0
Original line number Diff line number Diff line
@@ -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);

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