Direct Mem Pool vs Indirect mem pool creation

[Abdullah Ömer Yamaç]

I found the answer in the comments: "/* Creates a shallow copy of mbuf */"
for the rte_pktmbuf_clone. Thanks

On Fri, Sep 1, 2023 at 4:31 PM omer yamac <aomeryamac at gmail.com> wrote:

> 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 at 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
>>
>>
>>
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