Hi Sergio, On 02/16/2015 05:08 PM, Sergio Gonzalez Monroy wrote: > This patch removes all references to RTE_MBUF_REFCNT, setting the refcnt > field in the mbuf struct permanently. > > Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy at intel.com>
I think removing the refcount compile option goes in the right direction. However, activating the refcount will break the applications that reserve a private zone in mbufs. This is due to the macros RTE_MBUF_TO_BADDR() and RTE_MBUF_FROM_BADDR() that suppose that the beginning of the mbuf is 128 bytes (sizeof mbuf) before the data buffer. For RTE_MBUF_TO_BADDR(), it's relatively easy to replace it. The mbuf pool could store the size of the private size like it's done for mbp_priv->mbuf_data_room_size. Using rte_mempool_from_obj(m) or m->pool, we can retrieve the mbuf pool and this value, then compute the buffer address. For RTE_MBUF_FROM_BADDR(), it's more complex. We could ensure that a backpointer to the mbuf is always located before the data buffer, but it looks difficult to do. Another idea would be to add a field in indirect mbufs that stores the pointer to the "parent" mbuf. Regards, Olivier