Subject: Re: [PATCH v2 net-next] sctp: Add support to per-association statistics via a new SCTP_GET_ASSOC_STATS call

From: Vlad Yasevich <[email-masked]>
Date: Tue, 27 Nov 2012 20:40:29 -0500

On 11/27/2012 05:08 PM, Michele Baldessari wrote:
> Hi Vlad,
>
> thanks a lot for your review.
>
> On Mon, Nov 19, 2012 at 11:01:46AM -0500, Vlad Yasevich wrote:
> <snip>
>>> @@ -1152,8 +1156,11 @@ static void sctp_assoc_bh_rcv(struct work_struct *work)
>>>   		 */
>>>   		if (sctp_chunk_is_data(chunk))
>>>   			asoc->peer.last_data_from = chunk->transport;
>>> -		else
>>> +		else {
>>>   			SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
>>> +			if (chunk->chunk_hdr->type == SCTP_CID_SACK)
>>> +				asoc->stats.isacks++;
>>> +		}
>>
>> Should the above include asoc->stats.ictrlchunks++; just like ep_bh_rcv()?
>
> Indeed, I will add that.
>
>>>
>>>   		if (chunk->transport)
>>>   			chunk->transport->last_time_heard = jiffies;
>>> diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
>>> index 1859e2b..32ab55b 100644
>>> --- a/net/sctp/endpointola.c
>>> +++ b/net/sctp/endpointola.c
>>> @@ -480,8 +480,11 @@ normal:
>>>   		 */
>>>   		if (asoc && sctp_chunk_is_data(chunk))
>>>   			asoc->peer.last_data_from = chunk->transport;
>>> -		else
>>> +		else {
>>>   			SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
>>> +			if (asoc)
>>> +				asoc->stats.ictrlchunks++;
>>> +		}
>>>
>>>   		if (chunk->transport)
>>>   			chunk->transport->last_time_heard = jiffies;
>>> diff --git a/net/sctp/input.c b/net/sctp/input.c
>>> index 8bd3c27..54c449b 100644
>>> --- a/net/sctp/input.c
>>> +++ b/net/sctp/input.c
>>> @@ -281,6 +281,8 @@ int sctp_rcv(struct sk_buff *skb)
>>>   		SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ);
>>>   		sctp_inq_push(&chunk->rcvr->inqueue, chunk);
>>>   	}
>>> +	if (asoc)
>>> +		asoc->stats.ipackets++;
>>>
>>>   	sctp_bh_unlock_sock(sk);
>>
>> This needs a bit more thought.  Current counting behaves differently
>> depending on whether the user holds a socket lock or not.
>> If the user holds the lock, we'll end counting the packet before it is
>> processed.  If the user isn't holding the lock, we'll count the packet after
>> it is processed.
>
> I see. What do you prefer: use atomic64 for this specific counter or
> since it is a temporary miscount we go ahead and ignore it or do you
> have other approaches in mind?

You could count it in sctp_inq_push...  Would that make sense?

-vlad