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From: Ferruh Yigit <ferruh.yigit@intel.com>
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Date: Thu, 25 Aug 2016 14:51:39 +0100
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Subject: Re: [dpdk-dev] dpdk 16.07,
 issues with rte_mempool_create and rte_kni_alloc()
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On 8/10/2016 11:51 AM, Ferruh Yigit wrote:
> Hi Gopakumar,
> 
> On 8/4/2016 5:14 PM, Ferruh Yigit wrote:
>> On 8/1/2016 10:19 PM, Gopakumar Choorakkot Edakkunni wrote:
>>> Well, for my purpose I just ended up creating a seperate/smaller pool
>>> earlier during bootup to try to guarantee its from one memseg.
>>>
>>> But I am assuming that this KNI restriction is something thats "currently"
>>> not fixed and is "fixable" ? 
>>
>>
>>> Any ideas on what the summary of the reason
>>> for this restriction is - I was gonna check if I can fix that
>>
>> KNI expects all mbufs are from a physically continuous memory. This is
>> because of current address translation implementation.
>>
>> mbufs allocated in userspace and accessed from both user and kernel
>> space, so mbuf userspace virtual address needs to be converted into
>> kernelspace virtual address.
>>
>> Currently this address translation done by first calculating an offset
>> between virtual addresses using first filed of mempool, later applying
>> same offset to all mbufs. This is why all mbufs should be in physically
>> continuous memory.
>>
>> I think this address translation can be done in different way which can
>> remove the restriction, but not sure about the effect of the
>> performance. I will send a patch for this.
> 
> I have sent a patch to remove KNI restriction:
> http://dpdk.org/dev/patchwork/patch/15171/
> 
> Can you please test this patch with a mempool with multiple memzone?
> You need to remove following check in KNI manually:
>     if (mp->nb_mem_chunks != 1)
>         goto kni_fail;

Hi Gopakumar,

Off the list.

Any chance to test this?

Thanks,
ferruh