Commit a8735855 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
Browse files

xdp: remove net_device names from xdp_redirect tracepoint 



There is too much overhead in the current trace_xdp_redirect
tracepoint as it does strcpy and strlen on the net_device names.

Besides, exposing the ifindex/index is actually the information that
is needed in the tracepoint to diagnose issues.  When a lookup fails
(either ifindex or devmap index) then there is a need for saying which
to_index that have issues.

V2: Adjust args to be aligned with trace_xdp_exception.

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2886447d

include/trace/events/xdp.h

+12 −12
Original line number Diff line number Diff line
@@ -51,33 +51,33 @@ TRACE_EVENT(xdp_exception, 


TRACE_EVENT(xdp_redirect,



	TP_PROTO(const struct net_device *from,

		 const struct net_device *to,

		 const struct bpf_prog *xdp, u32 act, int err),

	TP_PROTO(const struct net_device *dev,

		 const struct bpf_prog *xdp, u32 act,

		 int to_index, int err),



	TP_ARGS(from, to, xdp, act, err),

	TP_ARGS(dev, xdp, act, to_index, err),



	TP_STRUCT__entry(

		__string(name_from, from->name)

		__string(name_to, to->name)

		__array(u8, prog_tag, 8)

		__field(u32, act)

		__field(int, ifindex)

		__field(int, to_index)

		__field(int, err)

	),



	TP_fast_assign(

		BUILD_BUG_ON(sizeof(__entry->prog_tag) != sizeof(xdp->tag));

		memcpy(__entry->prog_tag, xdp->tag, sizeof(xdp->tag));

		__assign_str(name_from, from->name);

		__assign_str(name_to, to->name);

		__entry->act		= act;

		__entry->ifindex	= dev->ifindex;

		__entry->to_index	= to_index;

		__entry->err		= err;

	),



	TP_printk("prog=%s from=%s to=%s action=%s err=%d",

	TP_printk("prog=%s action=%s ifindex=%d to_index=%d err=%d",

		  __print_hex_str(__entry->prog_tag, 8),

		  __get_str(name_from), __get_str(name_to),

		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),

		  __entry->ifindex, __entry->to_index,

		  __entry->err)

);

#endif /* _TRACE_XDP_H */

net/core/filter.c

+3 −3
Original line number Diff line number Diff line
@@ -2524,7 +2524,7 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp, 
	if (likely(!err))

		ri->map_to_flush = map;

out:

	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);

	trace_xdp_redirect(dev, xdp_prog, XDP_REDIRECT, index, err);

	return err;

}
@@ -2548,7 +2548,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, 


	err = __bpf_tx_xdp(fwd, NULL, xdp, 0);

out:

	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);

	trace_xdp_redirect(dev, xdp_prog, XDP_REDIRECT, index, err);

	return err;

}

EXPORT_SYMBOL_GPL(xdp_do_redirect);
@@ -2582,7 +2582,7 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb, 


	skb->dev = fwd;

out:

	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);

	trace_xdp_redirect(dev, xdp_prog, XDP_REDIRECT, index, err);

	return err;

}

EXPORT_SYMBOL_GPL(xdp_do_generic_redirect);

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