[dpdk-users] rte_rxmbuf_alloc() fails

[황규민]

Thank you for your answer.
I finally found the culprit. It was my fault.
I allocated useless mbufs from a mempool so the mbufs consume the mempool
slightly.
Thank you Keith :)

2016-12-07 23:16 GMT+09:00 Wiles, Keith <keith.wiles at intel.com>:

>
> > On Dec 7, 2016, at 3:44 AM, 황규민 <hkm73560 at gmail.com> wrote:
> >
> > Hi,
> >
> > When I run my application DPDK doesn't receive any packets after about 3
> > minutes.
> > So I figured out why rte_rx_burst() returned 0 and the reason is
> > rte_rxmbuf_alloc() failure. rte_rxmbuf_alloc() == NULL.
> > I printed some statistics and it showed that the prod's head and cons'
> head
> > are same.
> > What does this mean?
> > And rte_mempool_empty and rte_mempool_full always failed.
>
> To me the basic problem for mbuf allocation fails is the mbufs are not
> being freed and there are many reasons for this to happen.
>
> Here are a few I have hit:
> - The number of mbufs created is smaller then the TX flush threshold in
> the PMD(s), which does not allow any packets to be freed until the
> threshold is hit.
> - The next one I have see is not checking the rte_eth_tx_burst() return
> code, which is the number of mbufs that were able to be placed on the TX
> ring. Then the application just blindly reuses the mbuf array pointer again
> not realizing some mbufs are still in the list creating a mbuf leak.
>
> DPDK is very well tested so I would not expect any of the currently
> released code to have any problems or bugs in not freeing mbufs.
>
> >
> > Thanks.
>
> Regards,
> Keith
>
>