[ovs-dev] [PATCH v4 3/5] dpif-netdev: Skip encap action during datapath execution

Sriharsha Basavapatna sriharsha.basavapatna at broadcom.com
Mon Jun 29 09:50:18 UTC 2020


In this patch we check if action processing (apart from OUTPUT action),
should be skipped for a given dp_netdev_flow. Specifically, we check if
the action is TNL_PUSH and if it has been offloaded to HW, then we do not
push the tunnel header in SW. The datapath only executes the OUTPUT action.
The packet will be encapsulated in HW during transmit.

Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna at broadcom.com>
---
 lib/dpif-netdev.c | 46 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 7adea8c40..b96a75d1f 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -114,6 +114,7 @@ COVERAGE_DEFINE(datapath_drop_invalid_port);
 COVERAGE_DEFINE(datapath_drop_invalid_bond);
 COVERAGE_DEFINE(datapath_drop_invalid_tnl_port);
 COVERAGE_DEFINE(datapath_drop_rx_invalid_packet);
+COVERAGE_DEFINE(datapath_skip_tunnel_push);
 
 /* Protects against changes to 'dp_netdevs'. */
 static struct ovs_mutex dp_netdev_mutex = OVS_MUTEX_INITIALIZER;
@@ -545,6 +546,16 @@ struct dp_netdev_flow {
     bool dead;
     uint32_t mark;               /* Unique flow mark assigned to a flow */
 
+    /* The next two members are used to support partial offloading of
+     * actions. The boolean flag tells if this flow has its actions partially
+     * offloaded. The egress port# tells if the action should be offloaded
+     * on the egress (output) port instead of the in-port for the flow. Note
+     * that we support flows with a single egress port action.
+     * (see MAX_ACTION_ATTRS for related comments).
+     */
+    bool partial_actions_offloaded;
+    odp_port_t  egress_offload_port;
+
     /* Statistics. */
     struct dp_netdev_flow_stats stats;
 
@@ -817,7 +828,8 @@ static void dp_netdev_execute_actions(struct dp_netdev_pmd_thread *pmd,
                                       bool should_steal,
                                       const struct flow *flow,
                                       const struct nlattr *actions,
-                                      size_t actions_len);
+                                      size_t actions_len,
+                                      const struct dp_netdev_flow *dp_flow);
 static void dp_netdev_input(struct dp_netdev_pmd_thread *,
                             struct dp_packet_batch *, odp_port_t port_no);
 static void dp_netdev_recirculate(struct dp_netdev_pmd_thread *,
@@ -3954,7 +3966,7 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
     dp_packet_batch_init_packet(&pp, execute->packet);
     pp.do_not_steal = true;
     dp_netdev_execute_actions(pmd, &pp, false, execute->flow,
-                              execute->actions, execute->actions_len);
+                              execute->actions, execute->actions_len, NULL);
     dp_netdev_pmd_flush_output_packets(pmd, true);
 
     if (pmd->core_id == NON_PMD_CORE_ID) {
@@ -6672,7 +6684,7 @@ packet_batch_per_flow_execute(struct packet_batch_per_flow *batch,
     actions = dp_netdev_flow_get_actions(flow);
 
     dp_netdev_execute_actions(pmd, &batch->array, true, &flow->flow,
-                              actions->actions, actions->size);
+                              actions->actions, actions->size, flow);
 }
 
 static inline void
@@ -6967,7 +6979,7 @@ handle_packet_upcall(struct dp_netdev_pmd_thread *pmd,
      * we'll send the packet up twice. */
     dp_packet_batch_init_packet(&b, packet);
     dp_netdev_execute_actions(pmd, &b, true, &match.flow,
-                              actions->data, actions->size);
+                              actions->data, actions->size, NULL);
 
     add_actions = put_actions->size ? put_actions : actions;
     if (OVS_LIKELY(error != ENOSPC)) {
@@ -7202,6 +7214,7 @@ dp_netdev_recirculate(struct dp_netdev_pmd_thread *pmd,
 struct dp_netdev_execute_aux {
     struct dp_netdev_pmd_thread *pmd;
     const struct flow *flow;
+    const struct dp_netdev_flow *dp_flow;    /* for partial action offload */
 };
 
 static void
@@ -7346,7 +7359,7 @@ dp_execute_userspace_action(struct dp_netdev_pmd_thread *pmd,
     if (!error || error == ENOSPC) {
         dp_packet_batch_init_packet(&b, packet);
         dp_netdev_execute_actions(pmd, &b, should_steal, flow,
-                                  actions->data, actions->size);
+                                  actions->data, actions->size, NULL);
     } else if (should_steal) {
         dp_packet_delete(packet);
         COVERAGE_INC(datapath_drop_userspace_action_error);
@@ -7455,6 +7468,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
     int type = nl_attr_type(a);
     struct tx_port *p;
     uint32_t packet_count, packets_dropped;
+    struct dp_netdev_flow *dp_flow = aux->dp_flow;
 
     switch ((enum ovs_action_attr)type) {
     case OVS_ACTION_ATTR_OUTPUT:
@@ -7477,9 +7491,20 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
         }
         dp_packet_batch_apply_cutlen(packets_);
         packet_count = dp_packet_batch_size(packets_);
-        if (push_tnl_action(pmd, a, packets_)) {
-            COVERAGE_ADD(datapath_drop_tunnel_push_error,
-                         packet_count);
+        /* Execute tnl_push action in SW, if it is not offloaded as a partial
+         * action in HW. Otherwise, HW pushes the tunnel header during output
+         * processing. There's a small window here in which the offload thread
+         * offloads the flow, but the partial_actions_offloaded flag is still
+         * not set. In this case, as the packet is already encapsulated, it
+         * wouldn't match the offloaded flow and the action won't be executed
+         * in HW.
+         */
+        if (!dp_flow || !dp_flow->partial_actions_offloaded) {
+            if (push_tnl_action(pmd, a, packets_)) {
+                COVERAGE_ADD(datapath_drop_tunnel_push_error, packet_count);
+            }
+        } else {
+            COVERAGE_ADD(datapath_skip_tunnel_push, packet_count);
         }
         return;
 
@@ -7771,9 +7796,10 @@ static void
 dp_netdev_execute_actions(struct dp_netdev_pmd_thread *pmd,
                           struct dp_packet_batch *packets,
                           bool should_steal, const struct flow *flow,
-                          const struct nlattr *actions, size_t actions_len)
+                          const struct nlattr *actions, size_t actions_len,
+                          const struct dp_netdev_flow *dp_flow)
 {
-    struct dp_netdev_execute_aux aux = { pmd, flow };
+    struct dp_netdev_execute_aux aux = { pmd, flow, dp_flow };
 
     odp_execute_actions(&aux, packets, should_steal, actions,
                         actions_len, dp_execute_cb);
-- 
2.25.0.rc2



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