skb: Add tracepoints to freeing skb (07dc22e7) · Commits · 戴 / test

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>

include/trace/events/skb.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -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),

net/core/datagram.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

net/core/dev.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}

net/core/skbuff.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

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