Use thread local storage for thread index

This patch deprecates stack-based thread identification,
Also removes requirement that thread stacks are adjacent.

Finally, possibly annoying for some folks, it renames
all occurences of cpu_index and cpu_number with thread
index. Using word "cpu" is misleading here as thread can
be migrated ti different CPU, and also it is not related
to linux cpu index.

Change-Id: I68cdaf661e701d2336fc953dcb9978d10a70f7c1
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/ip/ip4_input.c b/src/vnet/ip/ip4_input.c
index ba200a9..3b08f4b 100644
--- a/src/vnet/ip/ip4_input.c
+++ b/src/vnet/ip/ip4_input.c
@@ -85,7 +85,7 @@
   vlib_node_runtime_t *error_node =
     vlib_node_get_runtime (vm, ip4_input_node.index);
   vlib_simple_counter_main_t *cm;
-  u32 cpu_index = os_get_cpu_number ();
+  u32 thread_index = vlib_get_thread_index ();
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
@@ -178,8 +178,8 @@
 	  vnet_feature_arc_start (arc0, sw_if_index0, &next0, p0);
 	  vnet_feature_arc_start (arc1, sw_if_index1, &next1, p1);
 
-	  vlib_increment_simple_counter (cm, cpu_index, sw_if_index0, 1);
-	  vlib_increment_simple_counter (cm, cpu_index, sw_if_index1, 1);
+	  vlib_increment_simple_counter (cm, thread_index, sw_if_index0, 1);
+	  vlib_increment_simple_counter (cm, thread_index, sw_if_index1, 1);
 
 	  /* Punt packets with options or wrong version. */
 	  if (PREDICT_FALSE (ip0->ip_version_and_header_length != 0x45))
@@ -299,7 +299,7 @@
 	  vnet_buffer (p0)->ip.adj_index[VLIB_RX] = ~0;
 	  vnet_feature_arc_start (arc0, sw_if_index0, &next0, p0);
 
-	  vlib_increment_simple_counter (cm, cpu_index, sw_if_index0, 1);
+	  vlib_increment_simple_counter (cm, thread_index, sw_if_index0, 1);
 
 	  /* Punt packets with options or wrong version. */
 	  if (PREDICT_FALSE (ip0->ip_version_and_header_length != 0x45))