udp: add tracepoints for queueing skb to rcvbuf
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>
diff --git a/include/trace/events/udp.h b/include/trace/events/udp.h
new file mode 100644
index 0000000..a664bb9
--- /dev/null
+++ b/include/trace/events/udp.h
@@ -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>