[ovs-dev] [PATCH 5/5] lib/netdev-dpdk: copy large packet to multi-segment mbufs

Michael Qiu qdy220091330 at gmail.com
Thu Oct 27 06:15:24 UTC 2016


Currently, one packet is only copied to one segment
in function dpdk_do_tx_copy(),  this could be an issue
when a jumboframe comes, especially for multipile segments.

This patch calculate the segment number needed by the packet and
copy the data to different segments.

Signed-off-by: Michael Qiu <qiudayu at chinac.com>
Signed-off-by: Jijiang Liu <liujijiang at chinac.com>
---
 lib/netdev-dpdk.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 48 insertions(+), 7 deletions(-)

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index ad92504..abb3b53 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -1554,9 +1554,10 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
 #endif
     struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
     struct rte_mbuf *mbufs[PKT_ARRAY_SIZE];
+    struct rte_mbuf *temp, *head = NULL;
     int dropped = 0;
     int newcnt = 0;
-    int i;
+    int i, j, nb_segs;
 
     /* If we are on a non pmd thread we have to use the mempool mutex, because
      * every non pmd thread shares the same mempool cache */
@@ -1569,6 +1570,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
 
     for (i = 0; i < batch->count; i++) {
         int size = dp_packet_size(batch->packets[i]);
+        int max_data_len, tmp_len;
 
         if (OVS_UNLIKELY(size > dev->max_packet_len)) {
             VLOG_WARN_RL(&rl, "Too big size %d max_packet_len %d",
@@ -1578,7 +1580,24 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
             continue;
         }
 
-        mbufs[newcnt] = rte_pktmbuf_alloc(dev->dpdk_mp->mp);
+        temp = mbufs[newcnt] = rte_pktmbuf_alloc(dev->dpdk_mp->mp);
+
+        /* all new allocated mbuf's max data len is the same */
+        max_data_len = temp->buf_len - temp->data_off;
+
+        nb_segs = size/max_data_len;
+        if (size % max_data_len)
+            nb_segs = nb_segs + 1;
+
+        for (j = 1; j < nb_segs; j++) {
+            temp->next = rte_pktmbuf_alloc(dev->dpdk_mp->mp);
+            if (!temp->next) {
+                rte_pktmbuf_free(mbufs[newcnt]);
+                mbufs[newcnt] = NULL;
+                break;
+            }
+            temp = temp->next;
+        }
 
         if (!mbufs[newcnt]) {
             dropped += batch->count - i;
@@ -1586,15 +1605,37 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
         }
 
         /* We have to do a copy for now */
-        memcpy(rte_pktmbuf_mtod(mbufs[newcnt], void *),
-               dp_packet_data(batch->packets[i]), size);
+        rte_pktmbuf_pkt_len(mbufs[newcnt]) = size;
+        temp = mbufs[newcnt];
+        tmp_len = size < max_data_len ? size: max_data_len;
+        if (batch->packets[i]->source == DPBUF_DPDK) {
+            head = &(batch->packets[i]->mbuf);
+            while (temp && head && size > 0) {
+                rte_memcpy(rte_pktmbuf_mtod(temp, void*), dp_packet_data((struct dp_packet *)head),tmp_len);
+                rte_pktmbuf_data_len(temp) = tmp_len;
+                head = head->next;
+                size = size - tmp_len;
+                tmp_len =  size < max_data_len ? size: max_data_len;
+                temp = temp->next;
+            }
+        } else {
+            int offset = 0;
+            while (temp && size > 0) {
+                memcpy(rte_pktmbuf_mtod(temp, void *),
+                    dp_packet_at(batch->packets[i], offset,tmp_len), tmp_len);
+                rte_pktmbuf_data_len(temp) = tmp_len;
+                temp = temp->next;
+                size = size - tmp_len;
+                offset +=tmp_len;
+                tmp_len =  size < max_data_len ? size: max_data_len;
+            }
+        }
+
 
-        mbufs[newcnt]->nb_segs = batch->packets[i]->mbuf.nb_segs;
+        mbufs[newcnt]->nb_segs = nb_segs;
         mbufs[newcnt]->ol_flags = batch->packets[i]->mbuf.ol_flags;
         mbufs[newcnt]->packet_type = batch->packets[i]->mbuf.packet_type;
         mbufs[newcnt]->tx_offload = batch->packets[i]->mbuf.tx_offload;
-        rte_pktmbuf_data_len(mbufs[newcnt]) = size;
-        rte_pktmbuf_pkt_len(mbufs[newcnt]) = size;
 
         newcnt++;
     }
-- 
1.8.3.1




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