policer: move handoff checks into policer code

The IP punt policer currently checks if it needs to do worker thread
handoff based on the thread index stored in the policer. Move this
functionality into the policer code so it can be common for all users
of the policer.

Type: improvement
Signed-off-by: Brian Russell <brian@graphiant.com>
Change-Id: Ia8d11e62898a58b19d7b27b296f8369baa3e5aa1

3 files changed, 29 insertions, 17 deletions

diff --git a/src/vnet/policer/node_funcs.c b/src/vnet/policer/node_funcs.c
index 30e5c505364..be8ce58799a 100644
--- a/src/vnet/policer/node_funcs.c
+++ b/src/vnet/policer/node_funcs.c
@@ -127,10 +127,10 @@ vnet_policer_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	  pi1 = pm->policer_index_by_sw_if_index[sw_if_index1];
 
 	  act0 = vnet_policer_police (vm, b0, pi0, time_in_policer_periods,
-				      POLICE_CONFORM /* no chaining */ );
+				      POLICE_CONFORM /* no chaining */, false);
 
 	  act1 = vnet_policer_police (vm, b1, pi1, time_in_policer_periods,
-				      POLICE_CONFORM /* no chaining */ );
+				      POLICE_CONFORM /* no chaining */, false);
 
 	  if (PREDICT_FALSE (act0 == QOS_ACTION_DROP)) /* drop action */
 	    {
@@ -201,7 +201,7 @@ vnet_policer_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	  pi0 = pm->policer_index_by_sw_if_index[sw_if_index0];
 
 	  act0 = vnet_policer_police (vm, b0, pi0, time_in_policer_periods,
-				      POLICE_CONFORM /* no chaining */ );
+				      POLICE_CONFORM /* no chaining */, false);
 
 	  if (PREDICT_FALSE (act0 == QOS_ACTION_DROP)) /* drop action */
 	    {
@@ -496,11 +496,9 @@ policer_classify_inline (vlib_main_t * vm,
 
 	      if (e0)
 		{
-		  act0 = vnet_policer_police (vm,
-					      b0,
-					      e0->next_index,
+		  act0 = vnet_policer_police (vm, b0, e0->next_index,
 					      time_in_policer_periods,
-					      e0->opaque_index);
+					      e0->opaque_index, false);
 		  if (PREDICT_FALSE (act0 == QOS_ACTION_DROP))
 		    {
 		      next0 = POLICER_CLASSIFY_NEXT_INDEX_DROP;
@@ -530,11 +528,9 @@ policer_classify_inline (vlib_main_t * vm,
 			vnet_classify_find_entry (t0, (u8 *) h0, hash0, now);
 		      if (e0)
 			{
-			  act0 = vnet_policer_police (vm,
-						      b0,
-						      e0->next_index,
+			  act0 = vnet_policer_police (vm, b0, e0->next_index,
 						      time_in_policer_periods,
-						      e0->opaque_index);
+						      e0->opaque_index, false);
 			  if (PREDICT_FALSE (act0 == QOS_ACTION_DROP))
 			    {
 			      next0 = POLICER_CLASSIFY_NEXT_INDEX_DROP;
diff --git a/src/vnet/policer/police.h b/src/vnet/policer/police.h
index f780bf65c50..5ad249ef40e 100644
--- a/src/vnet/policer/police.h
+++ b/src/vnet/policer/police.h
@@ -28,7 +28,8 @@ typedef enum
 {
   QOS_ACTION_DROP = 0,
   QOS_ACTION_TRANSMIT,
-  QOS_ACTION_MARK_AND_TRANSMIT
+  QOS_ACTION_MARK_AND_TRANSMIT,
+  QOS_ACTION_HANDOFF
 } __clib_packed qos_action_type_en;
 
 // This is the hardware representation of the policer.
diff --git a/src/vnet/policer/police_inlines.h b/src/vnet/policer/police_inlines.h
index fe0c754b7d4..9f56e1134d6 100644
--- a/src/vnet/policer/police_inlines.h
+++ b/src/vnet/policer/police_inlines.h
@@ -56,11 +56,9 @@ vnet_policer_mark (vlib_buffer_t *b, ip_dscp_t dscp)
 }
 
 static_always_inline u8
-vnet_policer_police (vlib_main_t * vm,
-		     vlib_buffer_t * b,
-		     u32 policer_index,
+vnet_policer_police (vlib_main_t *vm, vlib_buffer_t *b, u32 policer_index,
 		     u64 time_in_policer_periods,
-		     policer_result_e packet_color)
+		     policer_result_e packet_color, bool handoff)
 {
   qos_action_type_en act;
   u32 len;
@@ -72,8 +70,25 @@ vnet_policer_police (vlib_main_t * vm,
   vlib_prefetch_combined_counter (&policer_counters[POLICE_CONFORM],
 				  vm->thread_index, policer_index);
 
-  len = vlib_buffer_length_in_chain (vm, b);
   pol = &pm->policers[policer_index];
+
+  if (handoff)
+    {
+      if (PREDICT_FALSE (pol->thread_index == ~0))
+	/*
+	 * This is the first packet to use this policer. Set the
+	 * thread index in the policer to this thread and any
+	 * packets seen by this node on other threads will
+	 * be handed off to this one.
+	 *
+	 * This could happen simultaneously on another thread.
+	 */
+	clib_atomic_cmp_and_swap (&pol->thread_index, ~0, vm->thread_index);
+      else if (PREDICT_FALSE (pol->thread_index != vm->thread_index))
+	return QOS_ACTION_HANDOFF;
+    }
+
+  len = vlib_buffer_length_in_chain (vm, b);
   col = vnet_police_packet (pol, len, packet_color, time_in_policer_periods);
   act = pol->action[col];
   vlib_increment_combined_counter (&policer_counters[col], vm->thread_index,