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Commit 38edddb8 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Alexei Starovoitov
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xdp: add tracepoint for devmap like cpumap have 



Notice how this allow us get XDP statistic without affecting the XDP
performance, as tracepoint is no-longer activated on a per packet basis.

V5: Spotted by John Fastabend.
 Fix 'sent' also counted 'drops' in this patch, a later patch corrected
 this, but it was a mistake in this intermediate step.

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 5d053f9d

include/linux/bpf.h

+4 −2
Original line number Diff line number Diff line
@@ -492,7 +492,8 @@ struct xdp_buff; 
struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key);

void __dev_map_insert_ctx(struct bpf_map *map, u32 index);

void __dev_map_flush(struct bpf_map *map);

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp);

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,

		    struct net_device *dev_rx);



struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key);

void __cpu_map_insert_ctx(struct bpf_map *map, u32 index);
@@ -579,7 +580,8 @@ struct xdp_buff; 
struct bpf_dtab_netdev;



static inline

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp)

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,

		    struct net_device *dev_rx)

{

	return 0;

}

include/trace/events/xdp.h

+39 −0
Original line number Diff line number Diff line
@@ -229,6 +229,45 @@ TRACE_EVENT(xdp_cpumap_enqueue, 
		  __entry->to_cpu)

);



TRACE_EVENT(xdp_devmap_xmit,



	TP_PROTO(const struct bpf_map *map, u32 map_index,

		 int sent, int drops,

		 const struct net_device *from_dev,

		 const struct net_device *to_dev),



	TP_ARGS(map, map_index, sent, drops, from_dev, to_dev),



	TP_STRUCT__entry(

		__field(int, map_id)

		__field(u32, act)

		__field(u32, map_index)

		__field(int, drops)

		__field(int, sent)

		__field(int, from_ifindex)

		__field(int, to_ifindex)

	),



	TP_fast_assign(

		__entry->map_id		= map->id;

		__entry->act		= XDP_REDIRECT;

		__entry->map_index	= map_index;

		__entry->drops		= drops;

		__entry->sent		= sent;

		__entry->from_ifindex	= from_dev->ifindex;

		__entry->to_ifindex	= to_dev->ifindex;

	),



	TP_printk("ndo_xdp_xmit"

		  " map_id=%d map_index=%d action=%s"

		  " sent=%d drops=%d"

		  " from_ifindex=%d to_ifindex=%d",

		  __entry->map_id, __entry->map_index,

		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),

		  __entry->sent, __entry->drops,

		  __entry->from_ifindex, __entry->to_ifindex)

);



#endif /* _TRACE_XDP_H */



#include <trace/define_trace.h>

kernel/bpf/devmap.c

+23 −4
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#define DEV_MAP_BULK_SIZE 16

struct xdp_bulk_queue {

	struct xdp_frame *q[DEV_MAP_BULK_SIZE];

	struct net_device *dev_rx;

	unsigned int count;

};
@@ -219,6 +220,7 @@ static int bq_xmit_all(struct bpf_dtab_netdev *obj, 
			 struct xdp_bulk_queue *bq)

{

	struct net_device *dev = obj->dev;

	int sent = 0, drops = 0;

	int i;



	if (unlikely(!bq->count))
@@ -235,11 +237,18 @@ static int bq_xmit_all(struct bpf_dtab_netdev *obj, 
		int err;



		err = dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);

		if (err)

		if (err) {

			drops++;

			xdp_return_frame(xdpf);

		} else {

			sent++;

		}

	}

	bq->count = 0;



	trace_xdp_devmap_xmit(&obj->dtab->map, obj->bit,

			      sent, drops, bq->dev_rx, dev);

	bq->dev_rx = NULL;

	return 0;

}
@@ -296,18 +305,28 @@ struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key) 
/* Runs under RCU-read-side, plus in softirq under NAPI protection.

 * Thus, safe percpu variable access.

 */

static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)

static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf,

		      struct net_device *dev_rx)



{

	struct xdp_bulk_queue *bq = this_cpu_ptr(obj->bulkq);



	if (unlikely(bq->count == DEV_MAP_BULK_SIZE))

		bq_xmit_all(obj, bq);



	/* Ingress dev_rx will be the same for all xdp_frame's in

	 * bulk_queue, because bq stored per-CPU and must be flushed

	 * from net_device drivers NAPI func end.

	 */

	if (!bq->dev_rx)

		bq->dev_rx = dev_rx;



	bq->q[bq->count++] = xdpf;

	return 0;

}



int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp)

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,

		    struct net_device *dev_rx)

{

	struct net_device *dev = dst->dev;

	struct xdp_frame *xdpf;
@@ -319,7 +338,7 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp) 
	if (unlikely(!xdpf))

		return -EOVERFLOW;



	return bq_enqueue(dst, xdpf);

	return bq_enqueue(dst, xdpf, dev_rx);

}



static void *dev_map_lookup_elem(struct bpf_map *map, void *key)

net/core/filter.c

+1 −1
Original line number Diff line number Diff line
@@ -3067,7 +3067,7 @@ static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd, 
	case BPF_MAP_TYPE_DEVMAP: {

		struct bpf_dtab_netdev *dst = fwd;



		err = dev_map_enqueue(dst, xdp);

		err = dev_map_enqueue(dst, xdp, dev_rx);

		if (err)

			return err;

		__dev_map_insert_ctx(map, index);