Re: [dpdk-dev] rte_pktmbuf_alloc fails

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi,
Yep indeed, there is a bug in eth_pcap_tx() that can cause mbuf corruption.
I think it should be something like that instead:

--- a/lib/librte_pmd_pcap/rte_eth_pcap.c
+++ b/lib/librte_pmd_pcap/rte_eth_pcap.c
@@ -205,8 +205,9 @@ eth_pcap_tx(void *queue,
                mbuf = bufs[i];
                ret = pcap_sendpacket(tx_queue->pcap, (u_char*) mbuf->pkt.data,
                                mbuf->pkt.data_len);
-               if(likely(!ret))
-                       num_tx++;
+               if(unlikely(ret != 0))
+                       break;
+               num_tx++;
                rte_pktmbuf_free(mbuf);
        }

Thanks
Konstantin

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Olivier MATZ
Sent: Monday, April 07, 2014 8:27 AM
To: dev@dpdk.org
Cc: Meir Tseitlin
Subject: Re: [dpdk-dev] rte_pktmbuf_alloc fails

Hi Meir,

On Tuesday, April 01, 2014 02:53:47 PM Meir Tseitlin wrote:
> I think I found the problem - it was solved by manually calling 
> rte_pktmbuf_free for each packet.
> It seems that rte_pktmbuf_free is not automatically called from within 
> rte_eth_tx_burst if packets are sent to pcap device.

By looking at the eth_pcap_tx(pkts, nb_pkts) function, I think it may not work properly. I think it should return nb_pkts instead of num_tx. Indeed, if
pcap_sendpacket() fails -- I don't know in which case it can occur -- the function will return a number lower than nb_pkts, causing a caller like
l2fwd_send_burst() to free some mbufs. But all mbufs are already freed by eth_pcap_tx().

I don't know if it's related to your problem but it may help.

Regards,
Olivier