Subject: Re: [net-next RFC 4/8] macvlan: reduce the max number of taps to 8

From: Jason Wang <[email-masked]>
Date: Fri, 24 May 2013 13:14:40 +0800

On 05/23/2013 02:37 PM, Michael S. Tsirkin wrote:
> On Thu, May 23, 2013 at 11:12:29AM +0800, Jason Wang wrote:
>> To be same with tap.
>>
>> Signed-off-by: Jason Wang <[email-masked]>
> Well for tap the very specific reason was that
> there's an array of big queue structures,
> so we need to limit it to make it fit in a page.
> No such reason here right?

Right, one of the reason is that the flow caches itself occupies too
much space, I'd move it out of tun_struct.
>
> We need at least as much as tap to be compatible, so
> let's just make it 16 unconditionally?

Ok, in fact we can make it even more.
>
>> ---
>>  include/linux/if_macvlan.h |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
>> index e47ad46..32e943a 100644
>> --- a/include/linux/if_macvlan.h
>> +++ b/include/linux/if_macvlan.h
>> @@ -50,7 +50,7 @@ struct macvlan_pcpu_stats {
>>   * Maximum times a macvtap device can be opened. This can be used to
>>   * configure the number of receive queue, e.g. for multiqueue virtio.
>>   */
>> -#define MAX_MACVTAP_QUEUES	(NR_CPUS < 16 ? NR_CPUS : 16)
>> +#define MAX_MACVTAP_QUEUES	8
>>  
>>  #define MACVLAN_MC_FILTER_BITS	8
>>  #define MACVLAN_MC_FILTER_SZ	(1 << MACVLAN_MC_FILTER_BITS)
>> -- 
>> 1.7.1