Hello all,

 

I got issue, may be there is a missing solution in rte_kni.c or other parts.

 

There is not any function to free kni allocated bufs and rte_pktmbuf_free is not enough to handle it. (kni_free_mbufs is not reachable.)

 

In default-testing kni application works as below

 

1. Call rte_kni_rx_burst function to get messages
2. Then push to other KNI interface via rte_kni_tx_burst. There is no memory-leak because  kni_free_mbufs is called and freed unused allocations.

 

On the other hand, in my scenario

 

1. Call rte_kni_rx_burst func to get messages, burst_size is 32 but 1 packet is received from Kernel
2. Then try to free all messages via rte_pktmbuf_free
3. Freed 1 unit and 31 unit is not freed. memory leak

 

Other scenario,

 

1. Call rte_kni_rx_burst func to  get messages, burst_size is 32 but 1 packet is received from Kernel
2. Push to ethernet_device via rte_eth_tx_burst
3. There is not any free operation by rte_eth_tx_burst
4. Try to free via rte_pktmbuf_free
5. 1 unit is freed 31 unit is left in memory. Still memory leak

 

 

What i am missing ? I think same issue happens in version 17.11 .

 

unsigned

rte_kni_tx_burst(struct rte_kni *kni, struct rte_mbuf **mbufs, unsigned int num)

{

              num = RTE_MIN(kni_fifo_free_count(kni->rx_q), num);

              void *phy_mbufs[num];

              unsigned int ret;

              unsigned int i;

 

              for (i = 0; i < num; i++)

                            phy_mbufs[i] = va2pa_all(mbufs[i]);

 

              ret = kni_fifo_put(kni->rx_q, phy_mbufs, num);

 

              /* Get mbufs from free_q and then free them */

              kni_free_mbufs(kni);  ß------ Here is freeing unused allocations.

 

              return ret;

}

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 */

              if (ret)

                            kni_allocate_mbufs(kni);

 

              return ret;

}

 

static void

kni_free_mbufs(struct rte_kni *kni)

{

              int i, ret;

              struct rte_mbuf *pkts[MAX_MBUF_BURST_NUM];

 

              ret = kni_fifo_get(kni->free_q, (void **)pkts, MAX_MBUF_BURST_NUM);   <<ß- to free all allocated memory needs to use this function. (kni->free_q)

              if (likely(ret > 0)) {

                            for (i = 0; i < ret; i++)

                                          rte_pktmbuf_free(pkts[i]);

              }

}

 

 

Best Regards.

 

 

 

Hello all,

 

I think there is a memory leak for KNI.

 

Firstly, try to active trace modüle to follow memory management but could not. İt doesn’t create file and dont have any clue.

 

Run Command : -c dpdk_core_mask -d librte_net_virtio.so -d librte_mbuf.so -d librte_mempool.so -d librte_mempool_ring.so -d librte_mempool_stack.so -d librte_mempool_bucket.so -d librte_kni.so --log-level lib.kni:debug --log-level lib.eal:debug --log-level lib.ethdev:debug --trace=kni --trace-dir=/tmp/

 

 

Secondly, I used followed functions.

 

``code

  used_mpool  = rte_mempool_in_use_count(rdpdk_cfg->mbuf_pool);

  count_mpool = rte_mempool_avail_count(rdpdk_cfg->mbuf_pool);

``

 

After calling function rte_kni_rx_burst, 32 unit is allocated. Then i force to free message_buf (mbuf). It frees 1 unit. 31 units left in memory!

 

 

How to fix or understand this issue.

Follow logs,

 

 

 

1. (59383)  6:55:10    lrtc():3212> [KNI]Picked up 1 packets from port 0 [KNI:F000]   à 1 packet is received from Kernel that is allocate 32 unit
2. (59383)  6:55:10   print_mempool_tx():2511> [UseCount_mpool:468][avail_mpool:9931]
3. (59383)  6:55:10    pkni():2536> [KNI] i:0/1
4. (59383)  6:55:10    pkni():2616> [KNI][EGR]  P:[IPv6]  P:[0] [fe80::f816:3eff:fe93:f5fd]->[ff02::2] à Packet is a broadcast packet IPv6
5. (59383)  6:55:10    pkni():2620> [KNI][EGR][pkt-len:70]
6. (59383)  6:55:10   print_mempool_tx():2511> [UseCount_mpool:467][avail_mpool:9932] à mbuf is freed to understand mem-leak. İt is same happens after calling rte_eth_tx_burst
7. (59383)  6:55:10    lrtc():3212> [KNI]Picked up 1 packets from port 1 [KNI:F000] à 1 packet is received from Kernel that is allocate 32 unit 9932 to 9900 then same process happens and 31 units is not freed.
8. (59383)  6:55:10   print_mempool_tx():2511> [UseCount_mpool:499][avail_mpool:9900]
9. (59383)  6:55:10    pkni():2536> [KNI] i:0/1
10. (59383)  6:55:10    pkni():2616> [KNI][EGR]  P:[IPv6]    P:[1] [fe80::f816:3eff:fed2:9101]->[ff02::2]
11. (59383)  6:55:10    pkni():2620> [KNI][EGR][pkt-len:70]
12. (59383)  6:55:10   print_mempool_tx():2511> [UseCount_mpool:498][avail_mpool:9901]

 

 

Kernel : 5.4.0-146-generic #163-Ubuntu SMP Fri Mar 17 18:26:02 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Ubuntu 20.04

DPDK dpdk-stable-22.11.1

İgb_uio is used.

 

Best regards.

___

Yasin CANER

Lider Mühendis

Ulak Haberleşme A.Ş. Ankara