[ovs-dev] [PATCH 2/5] lib/dp-packet: copy additional packet info when do packet copy

[Kavanagh, Mark B]

>From: Michael Qiu [mailto:qdy220091330 at gmail.com]
>Sent: Monday, June 19, 2017 6:29 AM
>To: dev at openvswitch.org
>Cc: Kavanagh, Mark B <mark.b.kavanagh at intel.com>; blp at ovn.org; dball at vmware.com; Michael Qiu
><qiudayu at chinac.com>
>Subject: [PATCH 2/5] lib/dp-packet: copy additional packet info when do packet copy
>
>From: Michael Qiu <qiudayu at chinac.com>
>
>Currently, when doing packet copy, lots of DPDK mbuf's info
>will be missed, like packet type, ol_flags, etc.
>Those information is very important for DPDK to do
>packets processing.
>
>Signed-off-by: Michael Qiu <qiudayu at chinac.com>
>---
> lib/dp-packet.c   | 3 +++
> lib/netdev-dpdk.c | 4 ++++
> 2 files changed, 7 insertions(+)
>
>diff --git a/lib/dp-packet.c b/lib/dp-packet.c
>index ee2c449..9f872a1 100644
>--- a/lib/dp-packet.c
>+++ b/lib/dp-packet.c
>@@ -179,6 +179,9 @@ dp_packet_clone_with_headroom(const struct dp_packet *buffer, size_t
>headroom)
>     new_buffer->packet_type = buffer->packet_type;
> #ifdef DPDK_NETDEV
>     new_buffer->mbuf.ol_flags = buffer->mbuf.ol_flags;
>+    new_buffer->mbuf.tx_offload = buffer->mbuf.tx_offload;
>+    new_buffer->mbuf.packet_type = buffer->mbuf.packet_type;
>+    new_buffer->mbuf.nb_segs = buffer->mbuf.nb_segs;

Hi Michael,

In what use case would this information be useful?

Mirroring, perhaps?


> #else
>     new_buffer->rss_hash_valid = buffer->rss_hash_valid;
> #endif
>diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>index bba4de3..0485872 100644
>--- a/lib/netdev-dpdk.c
>+++ b/lib/netdev-dpdk.c
>@@ -1804,6 +1804,10 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch
>*batch)
>         memcpy(rte_pktmbuf_mtod(pkts[newcnt], void *),
>                dp_packet_data(batch->packets[i]), size);
>
>+        pkts[newcnt]->nb_segs = batch->packets[i]->mbuf.nb_segs;
>+        pkts[newcnt]->ol_flags = batch->packets[i]->mbuf.ol_flags;
>+        pkts[newcnt]->packet_type = batch->packets[i]->mbuf.packet_type;
>+        pkts[newcnt]->tx_offload = batch->packets[i]->mbuf.tx_offload;

Could you give an example of when it would be useful to copy info from mbufs which originate from non-DPDK source?
AFIA, non-DPDK sources don't currently update these particular fields - if I've missed something though, please let me know.

>         rte_pktmbuf_data_len(pkts[newcnt]) = size;
>         rte_pktmbuf_pkt_len(pkts[newcnt]) = size;
>
>--
>1.8.3.1