[ovs-dev] [ovs-dev, v4] dpif-netdev: Avoid reordering of packets in a batch with same megaflow

Ilya Maximets i.maximets at samsung.com
Tue Jul 10 15:11:45 UTC 2018


On 10.07.2018 17:48, Vishal Deep Ajmera wrote:
>>
>> This is potentially dangerous from the future modifications and hard to read for
>> reviewer/person who tries to understand how it works.
>>
>> Current implementation will fail if someone will change the logic of
>> 'DP_PACKET_BATCH_REFILL_FOR_EACH', for example.
>>
>> The key point is that 'DP_PACKET_BATCH_REFILL_FOR_EACH' and
>> 'dp_packet_batch_refill' manipulates with the batch size in a hidden from the
>> end user manner. Using of the 'packets_->count' directly requires knowledge of
>> how refilling works internally, but these functions was intended to hide internals
>> of batch manipulations.
>>
>> Also, as I understand, you're storing 'map_cnt' for each missed packet.
>> So, why not just use 'n_missed' for that purpose?
>>
> 
> map_cnt keeps count of not just the emc miss packet but also all subsequent
> packets (with emc hit) after one emc miss.

Yes. But we're talking about replacing 'packets_->count' with 'n_missed'.
Not about 'map_cnt'.


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