Thank you for the clarification. Now, I understand more clearly. May I ask
one more question? I used the rte_pktmbuf_clone function to duplicate the
packet. Then, the new packet is cloned to the indirect memory. After the
clone, I used the RTE_MBUF_DIRECT macro to check this, which returns false.
So, to get a direct buffer, I need to use the alloc function and copy the
data. Am I right?

I just want to use the "static inline int rte_vlan_insert(struct rte_mbuf
**m)" function; a direct buffer is necessary for this function.

On Fri, Sep 1, 2023 at 4:08 PM Thomas Monjalon <thomas@monjalon.net> wrote:

> 01/09/2023 14:47, omer yamac:
> > Hello,
> >
> > I need clarification while creating direct/indirect buffers for mbuf. I
> > couldn't find exact documentation, and I just looked over the
> fragmentation
> > test case and saw that two pools were created. One is a
> > direct pool, and the other is an indirect pool. Here are the methods to
> > create pools:
> > direct_pool = rte_pktmbuf_pool_create("FRAG_D_MBUF_POOL",
> >                           NUM_MBUFS, BURST, 0,
> >                           RTE_MBUF_DEFAULT_BUF_SIZE,
> >                           SOCKET_ID_ANY);
> > indirect_pool = rte_pktmbuf_pool_create("FRAG_I_MBUF_POOL",
> >                         NUM_MBUFS, BURST, 0,
> >                         0, SOCKET_ID_ANY)
> >
> > I couldn't see the exact difference. Just the "data_room_size" parameter
> is
> > different. If this parameter is 0, then is the pool indirect?
>
> A pool is neither direct or indirect, it is just a pool of buffers
> with a defined size for all buffers of a pool.
> You are free to create any pool for your needs.
>
> Now if you create a pool of buffers with size 0,
> we can expect you will save some data elsewhere,
> using rte_pktmbuf_attach_extbuf() for instance.
>
> More explanations can be found in the doc:
>
> https://doc.dpdk.org/guides/prog_guide/mbuf_lib.html#direct-and-indirect-buffers
>
>
>