Re: [dpdk-dev] [PATCH v5] vhost: add support for large buffers

[David Marchand <david.marchand@redhat.com>]

On Tue, Oct 15, 2019 at 9:00 PM Flavio Leitner <fbl@sysclose.org> wrote:
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 5b85b832d..da69ab1db 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -1289,6 +1289,93 @@ get_zmbuf(struct vhost_virtqueue *vq)
>         return NULL;
>  }
>
> +static void
> +virtio_dev_extbuf_free(void *addr __rte_unused, void *opaque)
> +{
> +       rte_free(opaque);
> +}
> +
> +static int
> +virtio_dev_extbuf_alloc(struct rte_mbuf *pkt, uint32_t size)
> +{
> +       struct rte_mbuf_ext_shared_info *shinfo = NULL;
> +       uint32_t total_len = RTE_PKTMBUF_HEADROOM + size;
> +       uint16_t buf_len;
> +       rte_iova_t iova;
> +       void *buf;
> +
> +       /* Try to use pkt buffer to store shinfo to reduce the amount of memory
> +        * required, otherwise store shinfo in the new buffer.
> +        */
> +       if (rte_pktmbuf_tailroom(pkt) >= sizeof(*shinfo))
> +               shinfo = rte_pktmbuf_mtod(pkt,
> +                                         struct rte_mbuf_ext_shared_info *);
> +       else {
> +               total_len += sizeof(*shinfo) + sizeof(uintptr_t);
> +               total_len = RTE_ALIGN_CEIL(total_len, sizeof(uintptr_t));
> +       }
> +
> +       if (unlikely(total_len > UINT16_MAX))
> +               return -ENOSPC;
> +
> +       buf_len = total_len;
> +       buf = rte_malloc(NULL, buf_len, RTE_CACHE_LINE_SIZE);

Using rte_malloc() means that the allocation can end up on any numa node.
This external buffer might end up on a different node than the mbuf
(which resides on mp->socket_id node).


-- 
David Marchand