Indirect mbuf handling

[narsimharaj pentam]

Added dev group.

On Tue, Dec 9, 2025 at 10:11 PM narsimharaj pentam <pnarsimharaj at gmail.com>
wrote:

> Hi
>
> I have a query related to ip fragmentation handling in DPDK.
>
> The DPDK application is trying to send a larger packet than the configured
> MTU on the interface, before sending the packet to the  i40e PMD the packet
> will
> undergo fragmentation . The DPDK library function
> *"rte_ipv4_fragment_packet"* is used for fragmentation. Function
> *rte_ipv4_fragment_packet* will create
> direct and indirect mbuf's  for a fragment , *the indirect buffers will
> have reference to the mbuf of the actual packet (zero copy).*
>
> The application will call function rte_eth_tx_burst to transmit fragments
> , which internally invokes *i40e_xmit_pkts *, the question here  is when
> should main application
> mbuf should be freed , can It be freed immediately  after i40e_xmit_pkts
> returns success, not sure because the mbuf's are queued up in software ring
> before actual transmit,
> I am worried about the fragments holding references to the main
> application buffer.
>
> Thanks.
>
> BR
> Narsimha
>
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