core: add tracepoints for queueing skb to rcvbuf

This patch adds 2 tracepoints to get a status of a socket receive queue
and related parameter.

One tracepoint is added to sock_queue_rcv_skb. It records rcvbuf size
and its usage. The other tracepoint is added to __sk_mem_schedule and
it records limitations of memory for sockets and current usage.

By using these tracepoints we're able to know detailed reason why kernel
drop the packet.

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>

1 files changed, 68 insertions, 0 deletions

diff --git a/include/trace/events/sock.h b/include/trace/events/sock.h
new file mode 100644
index 0000000..779abb9
--- /dev/null
+++ b/include/trace/events/sock.h
@@ -0,0 +1,68 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sock
+
+#if !defined(_TRACE_SOCK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SOCK_H
+
+#include <net/sock.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(sock_rcvqueue_full,
+
+	TP_PROTO(struct sock *sk, struct sk_buff *skb),
+
+	TP_ARGS(sk, skb),
+
+	TP_STRUCT__entry(
+		__field(int, rmem_alloc)
+		__field(unsigned int, truesize)
+		__field(int, sk_rcvbuf)
+	),
+
+	TP_fast_assign(
+		__entry->rmem_alloc = atomic_read(&sk->sk_rmem_alloc);
+		__entry->truesize   = skb->truesize;
+		__entry->sk_rcvbuf  = sk->sk_rcvbuf;
+	),
+
+	TP_printk("rmem_alloc=%d truesize=%u sk_rcvbuf=%d",
+		__entry->rmem_alloc, __entry->truesize, __entry->sk_rcvbuf)
+);
+
+TRACE_EVENT(sock_exceed_buf_limit,
+
+	TP_PROTO(struct sock *sk, struct proto *prot, long allocated),
+
+	TP_ARGS(sk, prot, allocated),
+
+	TP_STRUCT__entry(
+		__array(char, name, 32)
+		__field(long *, sysctl_mem)
+		__field(long, allocated)
+		__field(int, sysctl_rmem)
+		__field(int, rmem_alloc)
+	),
+
+	TP_fast_assign(
+		strncpy(__entry->name, prot->name, 32);
+		__entry->sysctl_mem = prot->sysctl_mem;
+		__entry->allocated = allocated;
+		__entry->sysctl_rmem = prot->sysctl_rmem[0];
+		__entry->rmem_alloc = atomic_read(&sk->sk_rmem_alloc);
+	),
+
+	TP_printk("proto:%s sysctl_mem=%ld,%ld,%ld allocated=%ld "
+		"sysctl_rmem=%d rmem_alloc=%d",
+		__entry->name,
+		__entry->sysctl_mem[0],
+		__entry->sysctl_mem[1],
+		__entry->sysctl_mem[2],
+		__entry->allocated,
+		__entry->sysctl_rmem,
+		__entry->rmem_alloc)
+);
+
+#endif /* _TRACE_SOCK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>