Re: [dpdk-dev] [PATCH v3 0/4] Allow using external memory without malloc

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 20-Dec-18 5:18 PM, Thomas Monjalon wrote:
> 20/12/2018 17:16, Stephen Hemminger:
>> On Thu, 20 Dec 2018 15:32:37 +0000
>> Anatoly Burakov <anatoly.burakov@intel.com> wrote:
>>
>>> Currently, the only way to use externally allocated memory
>>> is through rte_malloc API's. While this is fine for a lot
>>> of use cases, it may not be suitable for certain other use
>>> cases like manual memory management, etc.
>>>
>>> This patchset adds another API to register memory segments
>>> with DPDK (so that API's like ``rte_mem_virt2memseg`` could
>>> be relied on by PMD's and such), but not create a malloc
>>> heap out of them.
>>>
>>> Aside from the obvious (not adding memory to a heap), the
>>> other major difference between this API and the
>>> ``rte_malloc_heap_*`` external memory functions is the fact
>>> that no DMA mapping is performed automatically, as well as
>>> no mem event callbacks are triggered.
>>>
>>> This really draws a line in the sand, and there are now two
>>> ways of doing things - do everything automatically (using
>>> the ``rte_malloc_heap_*`` API's), or do everything manually
>>> (``rte_extmem_*`` and future DMA mapping API [1] that would
>>> replace ``rte_vfio_dma_map``). This way, the consistency of
>>> API is kept, and flexibility is also allowed.
>>>
>>> [1] https://mails.dpdk.org/archives/dev/2018-November/118175.html
>>
>> Where are the examples for this? Give a sample application maybe.
>>
>> Also there are no test cases.
> 
> It looks to be a big task, but yes, would be nice to have test
> of external memory allocation in DPDK unit tests.
> 

I imagine if i submitted patches for this, since it's test code, it can 
go into rc1? Or is that considered a "feature"?

I don't think it will be a lot of code, there are only 4 new API calls. 
Extending extmem autotest should do the trick. Adding a new testpmd mode 
is also possible but less trivial, and can be postponed to 19.05.

-- 
Thanks,
Anatoly