DPDK 22.11 - How to fix memory leak for KNI - How to debug

[Yasin CANER]

Hello,

I draw a flow via asciiflow to explain myself better. Problem is after
transmitting packets(mbufs) , it never puts in the kni->free_q to back to
the original pool. Each cycle, it allocates another 32 units that cause
leaks. Or I am missing something.

I already tried the rte_eth_tx_done_cleanup() function but it didn't fix
anything.

I am working on a patch to fix this issue but I am not sure if there
is another way.

Best regards.

https://pastebin.ubuntu.com/p/s4h5psqtgZ/


unsigned
rte_kni_rx_burst(struct rte_kni *kni, struct rte_mbuf **mbufs, unsigned int
num)
{
unsigned int ret = kni_fifo_get(kni->tx_q, (void **)mbufs, num);

/* If buffers removed, allocate mbufs and then put them into alloc_q */
/* Question, how to test buffers is removed or not?*/
if (ret)
    kni_allocate_mbufs(kni);

return ret;
}

Stephen Hemminger <stephen at networkplumber.org>, 8 May 2023 Pzt, 19:18
tarihinde şunu yazdı:

> On Mon, 8 May 2023 09:01:41 +0300
> Yasin CANER <yasinncaner at gmail.com> wrote:
>
> > Hello Stephen,
> >
> > Thank you for response, it helps me a lot. I understand problem better.
> >
> > After reading mbuf library (
> > https://doc.dpdk.org/guides/prog_guide/mempool_lib.html)  i realized
> that
> > 31 units allocation memory slot doesn't return to pool!
>
> If receive burst returns 1 mbuf, the other 31 pointers in the array
> are not valid. They do not point to mbufs.
>
> > 1 unit mbuf can be freed via rte_pktmbuf_free so it can back to pool.
> >
> > Main problem is that allocation doesn't return to original pool, act as
> > used. So, after following rte_pktmbuf_free
> > <
> http://doc.dpdk.org/api/rte__mbuf_8h.html#a1215458932900b7cd5192326fa4a6902
> >
> > function,
> > i realized that there is 2 function to helps to mbufs back to pool.
> >
> > These are rte_mbuf_raw_free
> > <
> http://doc.dpdk.org/api/rte__mbuf_8h.html#a9f188d53834978aca01ea101576d7432
> >
> >  and rte_pktmbuf_free_seg
> > <
> http://doc.dpdk.org/api/rte__mbuf_8h.html#a006ee80357a78fbb9ada2b0432f82f37
> >.
> > I will focus on them.
> >
> > If there is another suggestion, I will be very pleased.
> >
> > Best regards.
> >
> > Yasin CANER
> > Ulak
>
>
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