[ovs-dev] [PATCH v10 08/14] dp-packet: copy data from multi-seg. DPDK mbuf

Flavio Leitner fbl at sysclose.org
Wed Oct 3 18:26:44 UTC 2018


On Fri, Sep 28, 2018 at 05:15:09PM +0100, Tiago Lam wrote:
> From: Michael Qiu <qiudayu at chinac.com>
> 
> When doing packet clone, if packet source is from DPDK driver,
> multi-segment must be considered, and copy the segment's data one by
> one.
> 
> Also, lots of DPDK mbuf's info is missed during a copy, like packet
> type, ol_flags, etc.  That information is very important for DPDK to do
> packets processing.
> 
> Co-authored-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
> Co-authored-by: Tiago Lam <tiago.lam at intel.com>
> 
> Signed-off-by: Michael Qiu <qiudayu at chinac.com>
> Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
> Signed-off-by: Tiago Lam <tiago.lam at intel.com>
> Acked-by: Eelco Chaudron <echaudro at redhat.com>
> ---
>  lib/dp-packet.c   | 69 ++++++++++++++++++++++++++++++++++++++++++++++---------
>  lib/dp-packet.h   |  3 +++
>  lib/netdev-dpdk.c |  1 +
>  3 files changed, 62 insertions(+), 11 deletions(-)
> 
> diff --git a/lib/dp-packet.c b/lib/dp-packet.c
> index 167bf43..806640b 100644
> --- a/lib/dp-packet.c
> +++ b/lib/dp-packet.c
> @@ -48,6 +48,22 @@ dp_packet_use__(struct dp_packet *b, void *base, size_t allocated,
>      dp_packet_set_size(b, 0);
>  }
>  
> +#ifdef DPDK_NETDEV
> +void
> +dp_packet_copy_mbuf_flags(struct dp_packet *dst, const struct dp_packet *src)
> +{
> +    ovs_assert(dst != NULL && src != NULL);
> +    struct rte_mbuf *buf_dst = &(dst->mbuf);
> +    struct rte_mbuf buf_src = src->mbuf;
> +
> +    buf_dst->ol_flags = buf_src.ol_flags;
> +    buf_dst->packet_type = buf_src.packet_type;
> +    buf_dst->tx_offload = buf_src.tx_offload;

Nit: use dereferencing on both sides.

Also, since this is a simple function that only copies few fields, maybe it could
be in the dp-packet.h, so that netdev-dpdk.c can inline it.

> +}
> +#else
> +#define dp_packet_copy_mbuf_flags(arg1, arg2)

Nit2: since this is very specific to mbuf, we don't need to expose it
outside of DPDK.

> +#endif
> +
>  /* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
>   * memory starting at 'base'.  'base' should be the first byte of a region
>   * obtained from malloc().  It will be freed (with free()) if 'b' is resized or
> @@ -158,6 +174,44 @@ dp_packet_clone(const struct dp_packet *buffer)
>      return dp_packet_clone_with_headroom(buffer, 0);
>  }
>  
> +#ifdef DPDK_NETDEV
> +struct dp_packet *
> +dp_packet_clone_with_headroom(const struct dp_packet *b, size_t headroom) {
> +    struct dp_packet *new_buffer;
> +    uint32_t pkt_len = dp_packet_size(b);
> +
> +    /* copy multi-seg data */
> +    if (b->source == DPBUF_DPDK && !rte_pktmbuf_is_contiguous(&b->mbuf)) {
> +        void *dst = NULL;
> +        struct rte_mbuf *mbuf = CONST_CAST(struct rte_mbuf *, &b->mbuf);
> +
> +        new_buffer = dp_packet_new_with_headroom(pkt_len, headroom);
> +        dst = dp_packet_data(new_buffer);
> +        dp_packet_set_size(new_buffer, pkt_len);
> +
> +        if (!rte_pktmbuf_read(mbuf, 0, pkt_len, dst)) {

Here we leak new_buffer which is xmalloc'ed.

> +            return NULL;
> +        }
> +    } else {
> +        new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(b),
> +                                                        dp_packet_size(b),
> +                                                        headroom);
> +    }
> +
> +    /* Copy the following fields into the returned buffer: l2_pad_size,
> +     * l2_5_ofs, l3_ofs, l4_ofs, cutlen, packet_type and md. */
> +    memcpy(&new_buffer->l2_pad_size, &b->l2_pad_size,
> +           sizeof(struct dp_packet) -
> +           offsetof(struct dp_packet, l2_pad_size));
> +
> +    dp_packet_copy_mbuf_flags(new_buffer, b);
> +    if (dp_packet_rss_valid(new_buffer)) {
> +        new_buffer->mbuf.hash.rss = b->mbuf.hash.rss;
> +    }
> +
> +    return new_buffer;
> +}
> +#else
>  /* Creates and returns a new dp_packet whose data are copied from 'buffer'.
>   * The returned dp_packet will additionally have 'headroom' bytes of
>   * headroom. */
> @@ -165,32 +219,25 @@ struct dp_packet *
>  dp_packet_clone_with_headroom(const struct dp_packet *buffer, size_t headroom)
>  {
>      struct dp_packet *new_buffer;
> +    uint32_t pkt_len = dp_packet_size(buffer);
>  
>      new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(buffer),
> -                                                 dp_packet_size(buffer),
> -                                                 headroom);
> +                                                 pkt_len, headroom);
> +
>      /* Copy the following fields into the returned buffer: l2_pad_size,
>       * l2_5_ofs, l3_ofs, l4_ofs, cutlen, packet_type and md. */
>      memcpy(&new_buffer->l2_pad_size, &buffer->l2_pad_size,
>              sizeof(struct dp_packet) -
>              offsetof(struct dp_packet, l2_pad_size));
>  
> -#ifdef DPDK_NETDEV
> -    new_buffer->mbuf.ol_flags = buffer->mbuf.ol_flags;
> -#else
>      new_buffer->rss_hash_valid = buffer->rss_hash_valid;
> -#endif
> -
>      if (dp_packet_rss_valid(new_buffer)) {
> -#ifdef DPDK_NETDEV
> -        new_buffer->mbuf.hash.rss = buffer->mbuf.hash.rss;
> -#else
>          new_buffer->rss_hash = buffer->rss_hash;
> -#endif
>      }
>  
>      return new_buffer;
>  }
> +#endif

Nit3: Looks like the above functions share some code which could be on
another function or maybe move the copy specifics to a separate
functions.


>  /* Creates and returns a new dp_packet that initially contains a copy of the
>   * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
> diff --git a/lib/dp-packet.h b/lib/dp-packet.h
> index aab8f62..cbf002c 100644
> --- a/lib/dp-packet.h
> +++ b/lib/dp-packet.h
> @@ -124,6 +124,9 @@ void dp_packet_init_dpdk(struct dp_packet *);
>  void dp_packet_init(struct dp_packet *, size_t);
>  void dp_packet_uninit(struct dp_packet *);
>  
> +void dp_packet_copy_mbuf_flags(struct dp_packet *dst,
> +                               const struct dp_packet *src);
> +
>  struct dp_packet *dp_packet_new(size_t);
>  struct dp_packet *dp_packet_new_with_headroom(size_t, size_t headroom);
>  struct dp_packet *dp_packet_clone(const struct dp_packet *);
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 3b11546..8484239 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -2364,6 +2364,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
>          memcpy(rte_pktmbuf_mtod(pkts[txcnt], void *),
>                 dp_packet_data(packet), size);
>          dp_packet_set_size((struct dp_packet *)pkts[txcnt], size);
> +        dp_packet_copy_mbuf_flags((struct dp_packet *)pkts[txcnt], packet);
>  
>          txcnt++;
>      }
> -- 
> 2.7.4
> 
> _______________________________________________
> dev mailing list
> dev at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev

-- 
Flavio



More information about the dev mailing list