@@ -238,8 +238,83 @@ dp_packet_resize__(struct dp_packet *b, size_t new_headroom, size_t new_tailroom
switch (b->source) {
case DPBUF_DPDK:
- OVS_NOT_REACHED();
+ {
+ uint32_t miss_len;
+ uint16_t max_data_len, nb_segs;
+ int16_t head_diff = 0;
+ struct rte_mbuf *mbuf, *fmbuf;
+ struct rte_mempool *mp;
+
+ if (!netdev_dpdk_is_multi_segment_mbufs_enabled()) {
+ /* XXX: Handle single mbufs case better */
+ return;
+ }
+
+ /* Deal with headroom. Find out how much headroom we have, if any */
+ if (new_headroom != dp_packet_headroom(b)) {
+ head_diff = dp_packet_headroom(b) - new_headroom;
+ }
+
+ mbuf = CONST_CAST(struct rte_mbuf *, &b->mbuf);
+ /* Calculate missing length in need of allocation */
+ if (head_diff < 0) {
+ miss_len = new_allocated - head_diff - mbuf->pkt_len;
+ } else if (head_diff > 0){
+ miss_len = MIN(0, new_allocated - dp_packet_headroom(b)
+ - mbuf->pkt_len);
+ } else {
+ miss_len = new_allocated - mbuf->pkt_len;
+ }
+
+ /* All new allocated mbuf's max data len is the same */
+ max_data_len = mbuf->buf_len - mbuf->data_off;
+ /* Calculate # of needed mbufs to accomodate 'missing' */
+ nb_segs = miss_len / max_data_len;
+ if (miss_len % max_data_len) {
+ nb_segs += 1;
+ }
+ /* Proceed with the allocation of new mbufs */
+ mp = mbuf->pool;
+ fmbuf = mbuf;
+ mbuf = rte_pktmbuf_lastseg(mbuf);
+
+ for (int i = 0; i < nb_segs; i++) {
+ /* This takes care of initialising buf_len, data_len and other
+ * fields properly */
+ mbuf->next = rte_pktmbuf_alloc(mp);
+ if (!mbuf->next) {
+ /* XXX: Flag a WARN and return an error as this will likely
+ * result in undefined behaviour */
+ rte_pktmbuf_free(fmbuf);
+ fmbuf = NULL;
+ break;
+ }
+
+ fmbuf->nb_segs += 1;
+ }
+
+ /* Deal with headroom. If 'new_headroom' is bigger than available mbuf
+ * RTE_PKTMBUF_HEADROOM (defaults to 128B), the 'head_diff' calculated
+ * above will be negative and be used for shifting the data right.
+ * Otherwise 'head_diff' will be positive and will be used for shifting
+ * the data left.
+ * XXX: Doesn't verify or take into account that new_headroom may fall
+ * outside of an mbuf limits */
+ if (head_diff > 0) {
+ new_headroom = new_headroom;
+
+ dp_packet_shift(b, -head_diff);
+ } else if (head_diff < 0) {
+ new_headroom = dp_packet_headroom(b) + -head_diff;
+
+ dp_packet_shift(b, -head_diff);
+ }
+
+ new_base = dp_packet_base(b);
+
+ break;
+ }
case DPBUF_MALLOC:
if (new_headroom == dp_packet_headroom(b)) {
new_base = xrealloc(dp_packet_base(b), new_allocated);
When enabled with DPDK OvS relies on mbufs allocated by mempools to receive and output data on DPDK ports. Until now, each OvS dp_packet has only one mbuf associated, which is allocated with the maximum possible size, taking the MTU into account. This approach, however, doesn't allow us to increase the allocated size in an mbuf, if needed, since an mbuf is allocated and initialised upon mempool creation. Thus, in the current implementatin this is dealt with by calling OVS_NOTEACHED() and terminating OvS. To avoid this, and allow the allocated size to be increased, multiple mbufs can be linked together, in the multi-segment mbufs approach. Thus, dp_packet_resize__() has been modified to handle the DPBUF_DPDK case and allocate and link new mbufs together as needed. Signed-off-by: Tiago Lam <tiago.lam@intel.com> --- lib/dp-packet.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 76 insertions(+), 1 deletion(-)