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Subject: Re: [PATCH net-next 2/2] virtio-net: get rid of unnecessary container
 of rq stats
To:     Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Cc:     mst@redhat.com, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1533030219-9904-1-git-send-email-jasowang@redhat.com>
 <1533030219-9904-2-git-send-email-jasowang@redhat.com>
 <da012c13-e438-f45e-5c41-2f159e791f00@lab.ntt.co.jp>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <d11c65d8-20be-1a85-c687-c6f182264e41@redhat.com>
Date:   Wed, 1 Aug 2018 09:39:08 +0800
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On 2018年07月31日 18:02, Toshiaki Makita wrote:
> On 2018/07/31 18:43, Jason Wang wrote:
>> We don't maintain tx counters in rx stats any more. There's no need
>> for an extra container of rq stats.
>>
>> Cc: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>   drivers/net/virtio_net.c | 80 ++++++++++++++++++++++--------------------------
>>   1 file changed, 36 insertions(+), 44 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 72d3f68..14f661c 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -87,7 +87,8 @@ struct virtnet_sq_stats {
>>   	u64 kicks;
>>   };
>>   
>> -struct virtnet_rq_stat_items {
>> +struct virtnet_rq_stats {
>> +	struct u64_stats_sync syncp;
>>   	u64 packets;
>>   	u64 bytes;
>>   	u64 drops;
>> @@ -98,17 +99,8 @@ struct virtnet_rq_stat_items {
>>   	u64 kicks;
>>   };
>>   
>> -struct virtnet_rq_stats {
>> -	struct u64_stats_sync syncp;
>> -	struct virtnet_rq_stat_items items;
>> -};
> I'm not thinking removing sq stat is needed but even if it is I want to
> keep virtnet_rq_stats to avoid allocating unnecessary u64_stats_syncp on
> stack in virtnet_receive. I would just remove virtnet_rx_stats if necessary.

It's a nop on 64bit machines. And an unsigned on 32bit. So it's overhead 
could be ignored I think.

Thanks

>> -
>> -struct virtnet_rx_stats {
>> -	struct virtnet_rq_stat_items rx;
>> -};
>> -