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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>
This commit is contained in:
Satoru Moriya 2011-06-17 12:00:03 +00:00 committed by David S. Miller
parent 296f7ea75b
commit 3847ce32ae
3 changed files with 74 additions and 0 deletions
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68
include/trace/events/sock.h Normal file
View File

@ -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>

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

@ -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);

5
net/core/sock.c
View File

@ -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 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
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 @@ suppress_allocation:
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);