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Message-ID: <20110621104809.GB16311@hmsreliant.think-freely.org>
Date: Tue, 21 Jun 2011 06:48:10 -0400
From: Neil Horman <nhorman@...driver.com>
To: Satoru Moriya <satoru.moriya@....com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"davem@...emloft.net" <davem@...emloft.net>,
"dle-develop@...ts.sourceforge.net"
<dle-develop@...ts.sourceforge.net>,
Seiji Aguchi <seiji.aguchi@....com>
Subject: Re: [PATCH 2/2] core: add tracepoints for queueing skb to rcvbuf
On Fri, Jun 17, 2011 at 06:00:03PM -0400, Satoru Moriya wrote:
> 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@....com>
> ---
> include/trace/events/sock.h | 68 +++++++++++++++++++++++++++++++++++++++++++
> net/core/net-traces.c | 1 +
> net/core/sock.c | 5 +++
> 3 files changed, 74 insertions(+), 0 deletions(-)
> create mode 100644 include/trace/events/sock.h
>
> 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 @@ 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);
> --
> 1.7.1
>
>
>
Acked-by: Neil Horman <nhorman@...driver.com>
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