Subject: Re: [PATCH v3 net-next 1/5] ipv4: Update fib_table_lookup tracepoint to take common nexthop

From: David Ahern <[email-masked]>
Date: Tue, 2 Apr 2019 10:03:34 -0600

On 4/2/19 10:01 AM, Martin Lau wrote:
> On Mon, Apr 01, 2019 at 08:02:30PM -0700, David Ahern wrote:
>> From: David Ahern <[email-masked]>
>>
>> Update fib_table_lookup tracepoint to take a fib_nh_common struct and
>> dump the v6 gateway address if the nexthop uses it.
>>
>> Signed-off-by: David Ahern <[email-masked]>
>> ---
>>  include/trace/events/fib.h | 45 ++++++++++++++++++++++++++-------------------
>>  net/ipv4/fib_trie.c        |  2 +-
>>  2 files changed, 27 insertions(+), 20 deletions(-)
>>
>> diff --git a/include/trace/events/fib.h b/include/trace/events/fib.h
>> index 61ea7a24c8e5..7f83b6eafc5c 100644
>> --- a/include/trace/events/fib.h
>> +++ b/include/trace/events/fib.h
>> @@ -13,9 +13,9 @@
>>  TRACE_EVENT(fib_table_lookup,
>>  
>>  	TP_PROTO(u32 tb_id, const struct flowi4 *flp,
>> -		 const struct fib_nh *nh, int err),
>> +		 const struct fib_nh_common *nhc, int err),
>>  
>> -	TP_ARGS(tb_id, flp, nh, err),
>> +	TP_ARGS(tb_id, flp, nhc, err),
>>  
>>  	TP_STRUCT__entry(
>>  		__field(	u32,	tb_id		)
>> @@ -28,14 +28,17 @@ TRACE_EVENT(fib_table_lookup,
>>  		__field(	__u8,	flags		)
>>  		__array(	__u8,	src,	4	)
>>  		__array(	__u8,	dst,	4	)
>> -		__array(	__u8,	gw,	4	)
>> -		__array(	__u8,	saddr,	4	)
> saddr is no longer useful?
> 

I have not found it useful, and I use this tracepoint a lot. The line
length is really long as is and adding the ipv6 address just makes it worse.