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udp: add tracepoints for queueing skb to rcvbuf

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This patch adds a tracepoint to __udp_queue_rcv_skb to get the
return value of ip_queue_rcv_skb. It indicates why kernel drops
a packet at this point.

ip_queue_rcv_skb returns following values in the packet drop case:

rcvbuf is full                 : -ENOMEM
sk_filter returns error        : -EINVAL, -EACCESS, -ENOMEM, etc.
__sk_mem_schedule returns error: -ENOBUF

Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Satoru Moriya 2011-06-17 11:58:39 +00:00 committed by David S. Miller
parent dec17b7451
commit 296f7ea75b
3 changed files with 35 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

32
include/trace/events/udp.h Normal file
View file

@ -0,0 +1,32 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM udp
#if !defined(_TRACE_UDP_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_UDP_H
#include <linux/udp.h>
#include <linux/tracepoint.h>
TRACE_EVENT(udp_fail_queue_rcv_skb,
TP_PROTO(int rc, struct sock *sk),
TP_ARGS(rc, sk),
TP_STRUCT__entry(
__field(int, rc)
__field(__u16, lport)
),
TP_fast_assign(
__entry->rc = rc;
__entry->lport = inet_sk(sk)->inet_num;
),
TP_printk("rc=%d port=%hu", __entry->rc, __entry->lport)
);
#endif /* _TRACE_UDP_H */
/* This part must be outside protection */
#include <trace/define_trace.h>

1
net/core/net-traces.c
View file

@ -28,6 +28,7 @@
#include <trace/events/skb.h> #include <trace/events/skb.h>
#include <trace/events/net.h> #include <trace/events/net.h>
#include <trace/events/napi.h> #include <trace/events/napi.h>
#include <trace/events/udp.h>
EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb); EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);

2
net/ipv4/udp.c
View file

@ -105,6 +105,7 @@
#include <net/route.h> #include <net/route.h>
#include <net/checksum.h> #include <net/checksum.h>
#include <net/xfrm.h> #include <net/xfrm.h>
#include <trace/events/udp.h>
#include "udp_impl.h" #include "udp_impl.h"
struct udp_table udp_table __read_mostly; struct udp_table udp_table __read_mostly;
@ -1363,6 +1364,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
is_udplite); is_udplite);
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite); UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
kfree_skb(skb); kfree_skb(skb);
trace_udp_fail_queue_rcv_skb(rc, sk);
return -1; return -1;
} }