[dpdk-dev] Is contiguous hugepages memory still required in latest DPDKs?

[Ruslan Bilovol]

On 03/22/2017 02:08 PM, Ruslan Bilovol wrote:
> On 03/21/2017 04:41 PM, Sergio Gonzalez Monroy wrote:
>> The DPDK will still try to allocate contiguous hugepages.
>> Since DPDK v16.07 the mempool library is able to create a mempool with multiple chunks of memory.
>> You would still have the contig memory restriction for any other DPDK library or app.

Another question: are there any improvements in contiguous hugepages requirements in latest DPDK (v17.02)?

Thanks,
Ruslan


>>
>> Are you pre-allocating hugepages on boot (kernel cmdline) or runtime?
> I tried both cases, and there is no much difference between them.
> (I used debug prints in kernel to see physical address of preallocated hugepages
>
> Main issue is that linux kernel memory allocation algorithm was changed
> with "fair zone allocator policy" commits, and in my case need to
> pre-allocate 2x or even 3x more hugepages now.
>
> Regards,
> Ruslan
>
>>
>> Sergio
>>
>> On 21/03/2017 14:20, Ruslan Bilovol wrote:
>>> Hi,
>>>
>>> Recently after moving to 4.4 Linux kernel we found that DPDK v16.07
>>> can't find physically contiguous chunk of hugepages memory.
>>>
>>> I've tracked this down to kernel commits
>>>  81c0a2bb515f ("mm: page_alloc: fair zone allocator policy")
>>>  fff4068cba48 ("mm: page_alloc: revert NUMA aspect of fair allocation policy")
>>>  4ffeaf3560a5 ("mm: page_alloc: reduce cost of the fair zone allocation policy")
>>>
>>> These commits changed default page allocator behavior so it now allocates
>>> memory proportionally from preferred and lower zones. Hugepages
>>> are scattered proportionally among few memory zones, so possibility
>>> to find big physically contiguous chunk of hugepages memory is much lower.
>>>
>>> I see that there were some attempts to move from contiguous hugepages
>>> approach, like http://dpdk.org/ml/archives/dev/2016-March/035201.html
>>> Also some discussion here: http://dpdk.org/ml/archives/users/2016-October/001050.html
>>>
>>> The question: is contiguous hugepages memory still required in latest DPDKs,
>>> and if not, since which version?
>>>
>>> Thanks,
>>> Ruslan
>>>
>>
>