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>
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>
diff --git a/net/core/net-traces.c b/net/core/net-traces.c
index 13aab64..52380b1 100644
--- a/net/core/net-traces.c
+++ b/net/core/net-traces.c
@@ -28,6 +28,7 @@
#include <trace/events/skb.h>
#include <trace/events/net.h>
#include <trace/events/napi.h>
+#include <trace/events/sock.h>
#include <trace/events/udp.h>
EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);
diff --git a/net/core/sock.c b/net/core/sock.c
index 6e81978..76c4031 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -128,6 +128,8 @@
#include <linux/filter.h>
+#include <trace/events/sock.h>
+
#ifdef CONFIG_INET
#include <net/tcp.h>
#endif
@@ -292,6 +294,7 @@
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned)sk->sk_rcvbuf) {
atomic_inc(&sk->sk_drops);
+ trace_sock_rcvqueue_full(sk, skb);
return -ENOMEM;
}
@@ -1736,6 +1739,8 @@
return 1;
}
+ trace_sock_exceed_buf_limit(sk, prot, allocated);
+
/* Alas. Undo changes. */
sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
atomic_long_sub(amt, prot->memory_allocated);