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skb: Add tracepoints to freeing skb

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This patch adds tracepoint to consume_skb and add trace_kfree_skb
before __kfree_skb in skb_free_datagram_locked and net_tx_action.
Combinating with tracepoint on dev_hard_start_xmit, we can check
how long it takes to free transmitted packets. And using it, we can
calculate how many packets driver had at that time. It is useful when
a drop of transmitted packet is a problem.

            sshd-6828  [000] 112689.258154: consume_skb: skbaddr=f2d99bb8

Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Kaneshige Kenji <kaneshige.kenji@jp.fujitsu.com>
Cc: Izumo Taku <izumi.taku@jp.fujitsu.com>
Cc: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Scott Mcmillan <scott.a.mcmillan@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
LKML-Reference: <4C724364.50903@jp.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Koki Sanagi 2010-08-23 18:46:12 +09:00 committed by Frederic Weisbecker
parent cf66ba58b5
commit 07dc22e729
4 changed files with 21 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
include/trace/events/skb.h
View File

@ -35,6 +35,23 @@ TRACE_EVENT(kfree_skb,
__entry->skbaddr, __entry->protocol, __entry->location)
);
TRACE_EVENT(consume_skb,
TP_PROTO(struct sk_buff *skb),
TP_ARGS(skb),
TP_STRUCT__entry(
__field( void *, skbaddr )
),
TP_fast_assign(
__entry->skbaddr = skb;
),
TP_printk("skbaddr=%p", __entry->skbaddr)
);
TRACE_EVENT(skb_copy_datagram_iovec,
TP_PROTO(const struct sk_buff *skb, int len),

1
net/core/datagram.c
View File

@ -243,6 +243,7 @@ void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb)
unlock_sock_fast(sk, slow);
/* skb is now orphaned, can be freed outside of locked section */
trace_kfree_skb(skb, skb_free_datagram_locked);
__kfree_skb(skb);
}
EXPORT_SYMBOL(skb_free_datagram_locked);

2
net/core/dev.c
View File

@ -129,6 +129,7 @@
#include <linux/random.h>
#include <trace/events/napi.h>
#include <trace/events/net.h>
#include <trace/events/skb.h>
#include <linux/pci.h>
#include "net-sysfs.h"
@ -2576,6 +2577,7 @@ static void net_tx_action(struct softirq_action *h)
clist = clist->next;
WARN_ON(atomic_read(&skb->users));
trace_kfree_skb(skb, net_tx_action);
__kfree_skb(skb);
}
}

1
net/core/skbuff.c
View File

@ -466,6 +466,7 @@ void consume_skb(struct sk_buff *skb)
smp_rmb();
else if (likely(!atomic_dec_and_test(&skb->users)))
return;
trace_consume_skb(skb);
__kfree_skb(skb);
}
EXPORT_SYMBOL(consume_skb);