svm: split fifo into private and shared structs

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Id8e77e8b2623be719fd43a95e181eaa5b7df2b6e

25 files changed, 590 insertions, 445 deletions

diff --git a/src/plugins/hs_apps/echo_client.c b/src/plugins/hs_apps/echo_client.c
index 072d767fa6e..50d815748a5 100644
--- a/src/plugins/hs_apps/echo_client.c
+++ b/src/plugins/hs_apps/echo_client.c
@@ -65,9 +65,8 @@ send_data_chunk (echo_client_main_t * ecm, eclient_session_t * s)
 	  svm_fifo_t *f = s->data.tx_fifo;
 	  rv = clib_min (svm_fifo_max_enqueue_prod (f), bytes_this_chunk);
 	  svm_fifo_enqueue_nocopy (f, rv);
-	  session_send_io_evt_to_thread_custom (&f->master_session_index,
-						s->thread_index,
-						SESSION_IO_EVT_TX);
+	  session_send_io_evt_to_thread_custom (
+	    &f->shr->master_session_index, s->thread_index, SESSION_IO_EVT_TX);
 	}
       else
 	rv = app_send_stream (&s->data, test_data + test_buf_offset,
@@ -101,9 +100,8 @@ send_data_chunk (echo_client_main_t * ecm, eclient_session_t * s)
 	  hdr.lcl_port = at->lcl_port;
 	  svm_fifo_enqueue (f, sizeof (hdr), (u8 *) & hdr);
 	  svm_fifo_enqueue_nocopy (f, rv);
-	  session_send_io_evt_to_thread_custom (&f->master_session_index,
-						s->thread_index,
-						SESSION_IO_EVT_TX);
+	  session_send_io_evt_to_thread_custom (
+	    &f->shr->master_session_index, s->thread_index, SESSION_IO_EVT_TX);
 	}
       else
 	{
@@ -441,9 +439,9 @@ quic_echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   session->bytes_to_send = ecm->bytes_to_send;
   session->bytes_to_receive = ecm->no_return ? 0ULL : ecm->bytes_to_send;
   session->data.rx_fifo = s->rx_fifo;
-  session->data.rx_fifo->client_session_index = session_index;
+  session->data.rx_fifo->shr->client_session_index = session_index;
   session->data.tx_fifo = s->tx_fifo;
-  session->data.tx_fifo->client_session_index = session_index;
+  session->data.tx_fifo->shr->client_session_index = session_index;
   session->data.vpp_evt_q = ecm->vpp_event_queue[thread_index];
   session->vpp_session_handle = session_handle (s);
 
@@ -508,9 +506,9 @@ echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   session->bytes_to_send = ecm->bytes_to_send;
   session->bytes_to_receive = ecm->no_return ? 0ULL : ecm->bytes_to_send;
   session->data.rx_fifo = s->rx_fifo;
-  session->data.rx_fifo->client_session_index = session_index;
+  session->data.rx_fifo->shr->client_session_index = session_index;
   session->data.tx_fifo = s->tx_fifo;
-  session->data.tx_fifo->client_session_index = session_index;
+  session->data.tx_fifo->shr->client_session_index = session_index;
   session->data.vpp_evt_q = ecm->vpp_event_queue[thread_index];
   session->vpp_session_handle = session_handle (s);
 
@@ -589,7 +587,8 @@ echo_clients_rx_callback (session_t * s)
       return -1;
     }
 
-  sp = pool_elt_at_index (ecm->sessions, s->rx_fifo->client_session_index);
+  sp =
+    pool_elt_at_index (ecm->sessions, s->rx_fifo->shr->client_session_index);
   receive_data_chunk (ecm, sp);
 
   if (svm_fifo_max_dequeue_cons (s->rx_fifo))
diff --git a/src/plugins/hs_apps/proxy.c b/src/plugins/hs_apps/proxy.c
index fc66286a803..834d03f8dbd 100644
--- a/src/plugins/hs_apps/proxy.c
+++ b/src/plugins/hs_apps/proxy.c
@@ -309,7 +309,7 @@ proxy_rx_callback (session_t * s)
       if (svm_fifo_set_event (ao_tx_fifo))
 	{
 	  u32 ao_thread_index = ao_tx_fifo->master_thread_index;
-	  u32 ao_session_index = ao_tx_fifo->master_session_index;
+	  u32 ao_session_index = ao_tx_fifo->shr->master_session_index;
 	  if (session_send_io_evt_to_thread_custom (&ao_session_index,
 						    ao_thread_index,
 						    SESSION_IO_EVT_TX))
@@ -475,7 +475,7 @@ active_open_connected_callback (u32 app_index, u32 opaque,
    * Reset the active-open tx-fifo master indices so the active-open session
    * will receive data, etc.
    */
-  s->tx_fifo->master_session_index = s->session_index;
+  s->tx_fifo->shr->master_session_index = s->session_index;
   s->tx_fifo->master_thread_index = s->thread_index;
 
   /*
@@ -532,7 +532,7 @@ active_open_rx_callback (session_t * s)
   if (svm_fifo_set_event (proxy_tx_fifo))
     {
       u8 thread_index = proxy_tx_fifo->master_thread_index;
-      u32 session_index = proxy_tx_fifo->master_session_index;
+      u32 session_index = proxy_tx_fifo->shr->master_session_index;
       return session_send_io_evt_to_thread_custom (&session_index,
 						   thread_index,
 						   SESSION_IO_EVT_TX);
diff --git a/src/plugins/hs_apps/sapi/vpp_echo.c b/src/plugins/hs_apps/sapi/vpp_echo.c
index 4cce41edf95..a47a4d455d8 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo.c
@@ -69,9 +69,9 @@ echo_session_dequeue_notify (echo_session_t * s)
   int rv;
   if (!svm_fifo_set_event (s->rx_fifo))
     return;
-  if ((rv =
-       app_send_io_evt_to_vpp (s->vpp_evt_q, s->rx_fifo->master_session_index,
-			       SESSION_IO_EVT_RX, SVM_Q_WAIT)))
+  if ((rv = app_send_io_evt_to_vpp (s->vpp_evt_q,
+				    s->rx_fifo->shr->master_session_index,
+				    SESSION_IO_EVT_RX, SVM_Q_WAIT)))
     ECHO_FAIL (ECHO_FAIL_SEND_IO_EVT, "app_send_io_evt_to_vpp errored %d",
 	       rv);
   svm_fifo_clear_deq_ntf (s->rx_fifo);
@@ -542,7 +542,6 @@ session_accepted_handler (session_accepted_msg_t * mp)
 {
   app_session_evt_t _app_evt, *app_evt = &_app_evt;
   session_accepted_reply_msg_t *rmp;
-  svm_fifo_t *rx_fifo, *tx_fifo;
   echo_main_t *em = &echo_main;
   echo_session_t *session, *ls;
 
@@ -552,24 +551,22 @@ session_accepted_handler (session_accepted_msg_t * mp)
 		 "Unknown listener handle 0x%lx", mp->listener_handle);
       return;
     }
-  if (echo_segment_lookup (mp->segment_handle) == ~0)
+
+  /* Allocate local session and set it up */
+  session = echo_session_new (em);
+
+  if (echo_attach_session (mp->segment_handle, mp->server_rx_fifo,
+			   mp->server_tx_fifo, session))
     {
       ECHO_FAIL (ECHO_FAIL_ACCEPTED_WAIT_FOR_SEG_ALLOC,
 		 "accepted wait_for_segment_allocation errored");
       return;
     }
 
-  /* Allocate local session and set it up */
-  session = echo_session_new (em);
-  session->vpp_session_handle = mp->handle;
-
-  rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
-  rx_fifo->client_session_index = session->session_index;
-  tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  tx_fifo->client_session_index = session->session_index;
+  session->vpp_evt_q =
+    uword_to_pointer (mp->vpp_event_queue_address, svm_msg_q_t *);
 
-  session->rx_fifo = rx_fifo;
-  session->tx_fifo = tx_fifo;
+  session->vpp_session_handle = mp->handle;
 
   /* session->transport needed by app_send_dgram */
   clib_memcpy_fast (&session->transport.rmt_ip, &mp->rmt.ip,
@@ -581,10 +578,8 @@ session_accepted_handler (session_accepted_msg_t * mp)
   session->transport.lcl_port = em->uri_elts.port;
 
   session->vpp_session_handle = mp->handle;
-  session->start = clib_time_now (&em->clib_time);
-  session->vpp_evt_q = uword_to_pointer (mp->vpp_event_queue_address,
-					 svm_msg_q_t *);
   session->listener_index = ls->session_index;
+  session->start = clib_time_now (&em->clib_time);
 
   /* Add it to lookup table */
   ECHO_LOG (2, "Accepted session 0x%lx S[%u] -> 0x%lx S[%u]",
@@ -607,7 +602,6 @@ session_connected_handler (session_connected_msg_t * mp)
   echo_main_t *em = &echo_main;
   echo_session_t *session;
   u32 listener_index = htonl (mp->context);
-  svm_fifo_t *rx_fifo, *tx_fifo;
 
   clib_atomic_add_fetch (&em->max_sim_connects, 1);
 
@@ -621,24 +615,18 @@ session_connected_handler (session_connected_msg_t * mp)
     }
 
   session = echo_session_new (em);
-  if (echo_segment_lookup (mp->segment_handle) == ~0)
+
+  if (echo_attach_session (mp->segment_handle, mp->server_rx_fifo,
+			   mp->server_tx_fifo, session))
     {
       ECHO_FAIL (ECHO_FAIL_CONNECTED_WAIT_FOR_SEG_ALLOC,
 		 "connected wait_for_segment_allocation errored");
       return;
     }
-
-  rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
-  rx_fifo->client_session_index = session->session_index;
-  tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  tx_fifo->client_session_index = session->session_index;
-
-  session->rx_fifo = rx_fifo;
-  session->tx_fifo = tx_fifo;
-  session->vpp_session_handle = mp->handle;
-  session->start = clib_time_now (&em->clib_time);
   session->vpp_evt_q = uword_to_pointer (mp->vpp_event_queue_address,
 					 svm_msg_q_t *);
+  session->vpp_session_handle = mp->handle;
+  session->start = clib_time_now (&em->clib_time);
   session->listener_index = listener_index;
   /* session->transport needed by app_send_dgram */
   clib_memcpy_fast (&session->transport.lcl_ip, &mp->lcl.ip,
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_bapi.c b/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
index e71c0e9adba..c643cec2ce3 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
@@ -262,6 +262,39 @@ echo_segment_detach (u64 segment_handle)
   clib_spinlock_unlock (&em->segment_handles_lock);
 }
 
+int
+echo_attach_session (uword segment_handle, uword rxf_offset, uword txf_offset,
+		     echo_session_t *s)
+{
+  svm_fifo_shared_t *rx_fifo, *tx_fifo;
+  echo_main_t *em = &echo_main;
+  fifo_segment_t *fs;
+  u32 fs_index;
+
+  fs_index = echo_segment_lookup (segment_handle);
+  if (fs_index == (u32) ~0)
+    {
+      ECHO_LOG (0, "ERROR: segment for session %u is not mounted!",
+		s->session_index);
+      return -1;
+    }
+
+  rx_fifo = uword_to_pointer (rxf_offset, svm_fifo_shared_t *);
+  tx_fifo = uword_to_pointer (txf_offset, svm_fifo_shared_t *);
+  rx_fifo->client_session_index = s->session_index;
+  tx_fifo->client_session_index = s->session_index;
+
+  clib_spinlock_lock (&em->segment_handles_lock);
+
+  fs = fifo_segment_get_segment (&em->segment_main, fs_index);
+  s->rx_fifo = fifo_segment_alloc_fifo_w_shared (fs, rx_fifo);
+  s->tx_fifo = fifo_segment_alloc_fifo_w_shared (fs, tx_fifo);
+
+  clib_spinlock_unlock (&em->segment_handles_lock);
+
+  return 0;
+}
+
 /*
  *
  *  Binary API callbacks
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_common.h b/src/plugins/hs_apps/sapi/vpp_echo_common.h
index 0def7adab36..cd2bbb6038c 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_common.h
+++ b/src/plugins/hs_apps/sapi/vpp_echo_common.h
@@ -443,6 +443,8 @@ int echo_segment_attach (u64 segment_handle, char *name,
 			 ssvm_segment_type_t type, int fd);
 u32 echo_segment_lookup (u64 segment_handle);
 void echo_segment_detach (u64 segment_handle);
+int echo_attach_session (uword segment_handle, uword rxf_offset,
+			 uword txf_offset, echo_session_t *s);
 
 /* Binary API */
 
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_proto_udp.c b/src/plugins/hs_apps/sapi/vpp_echo_proto_udp.c
index 456113cdd7d..9689a83d76b 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_proto_udp.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo_proto_udp.c
@@ -126,24 +126,24 @@ udp_echo_reset_cb (session_reset_msg_t * mp, echo_session_t * s)
 static void
 udp_echo_bound_uri_cb (session_bound_msg_t * mp, echo_session_t * session)
 {
-  svm_fifo_t *rx_fifo, *tx_fifo;
   echo_main_t *em = &echo_main;
   u32 session_index = session->session_index;
   if (!em->i_am_master || em->uri_elts.transport_proto != TRANSPORT_PROTO_UDP)
     return;
 
-  rx_fifo = uword_to_pointer (mp->rx_fifo, svm_fifo_t *);
-  tx_fifo = uword_to_pointer (mp->tx_fifo, svm_fifo_t *);
-  rx_fifo->client_session_index = session_index;
-  tx_fifo->client_session_index = session_index;
+  if (echo_attach_session (mp->segment_handle, mp->rx_fifo, mp->tx_fifo,
+			   session))
+    {
+      ECHO_FAIL (ECHO_FAIL_ACCEPTED_WAIT_FOR_SEG_ALLOC,
+		 "accepted wait_for_segment_allocation errored");
+      return;
+    }
 
-  session->rx_fifo = rx_fifo;
-  session->tx_fifo = tx_fifo;
+  session->vpp_evt_q = uword_to_pointer (mp->vpp_evt_q, svm_msg_q_t *);
   session->transport.is_ip4 = mp->lcl_is_ip4;
   clib_memcpy_fast (&session->transport.lcl_ip, mp->lcl_ip,
 		    sizeof (ip46_address_t));
   session->transport.lcl_port = mp->lcl_port;
-  session->vpp_evt_q = uword_to_pointer (mp->vpp_evt_q, svm_msg_q_t *);
 
   echo_notify_event (em, ECHO_EVT_FIRST_QCONNECT);
   session->session_type = ECHO_SESSION_TYPE_STREAM;
diff --git a/src/plugins/unittest/segment_manager_test.c b/src/plugins/unittest/segment_manager_test.c
index 2e8261e1c90..c6f52972e51 100644
--- a/src/plugins/unittest/segment_manager_test.c
+++ b/src/plugins/unittest/segment_manager_test.c
@@ -670,8 +670,8 @@ segment_manager_test_fifo_ops (vlib_main_t * vm, unformat_input_t * input)
 		"fifo_segment_get_mem_status %s", states_str[rv]);
 
   /* (virtual) fifo size is still large as it is not updated */
-  SEG_MGR_TEST ((rx_fifo->size == most_grown), "rx_fifo->size %u",
-		rx_fifo->size);
+  SEG_MGR_TEST ((rx_fifo->shr->size == most_grown), "rx_fifo->size %u",
+		rx_fifo->shr->size);
 
   vnet_app_detach_args_t detach_args = {
     .app_index = attach_args.app_index,
diff --git a/src/plugins/unittest/session_test.c b/src/plugins/unittest/session_test.c
index d3a4e091647..862d81f4acb 100644
--- a/src/plugins/unittest/session_test.c
+++ b/src/plugins/unittest/session_test.c
@@ -1850,7 +1850,7 @@ session_test_mq_speed (vlib_main_t * vm, unformat_input_t * input)
   s.rx_fifo = rx_fifo;
   s.tx_fifo = tx_fifo;
   s.session_state = SESSION_STATE_READY;
-  counter = (u64 *) rx_fifo->head_chunk->data;
+  counter = (u64 *) rx_fifo->shr->head_chunk->data;
   start = vlib_time_now (vm);
 
   pid = fork ();
diff --git a/src/plugins/unittest/svm_fifo_test.c b/src/plugins/unittest/svm_fifo_test.c
index 6adba7e8e59..978dc10ff99 100644
--- a/src/plugins/unittest/svm_fifo_test.c
+++ b/src/plugins/unittest/svm_fifo_test.c
@@ -256,7 +256,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
    */
   rv = svm_fifo_enqueue (f, sizeof (u32), (u8 *) test_data);
   SFIFO_TEST ((rv == sizeof (u32)), "enqueued %d", rv);
-  SFIFO_TEST ((f->tail == 4), "fifo tail %u", f->tail);
+  SFIFO_TEST ((f->shr->tail == 4), "fifo tail %u", f->shr->tail);
 
   /*
    * Create 3 chunks in the future. The offsets are relative
@@ -264,7 +264,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
    */
   for (i = 0; i < 3; i++)
     {
-      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      offset = (2 * i + 1) * sizeof (u32) - f->shr->tail;
       data = (u8 *) (test_data + (2 * i + 1));
       if (i == 0)
 	{
@@ -286,14 +286,14 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
   if (verbose)
     vlib_cli_output (vm, "fifo after odd segs: %U", format_svm_fifo, f, 1);
 
-  SFIFO_TEST ((f->tail == 8), "fifo tail %u", f->tail);
+  SFIFO_TEST ((f->shr->tail == 8), "fifo tail %u", f->shr->tail);
   SFIFO_TEST ((svm_fifo_n_ooo_segments (f) == 2),
 	      "number of ooo segments %u", svm_fifo_n_ooo_segments (f));
 
   /*
    * Try adding a completely overlapped segment
    */
-  offset = 3 * sizeof (u32) - f->tail;
+  offset = 3 * sizeof (u32) - f->shr->tail;
   data = (u8 *) (test_data + 3);
   rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
   if (rv)
@@ -319,7 +319,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
    */
   for (i = 3; i > 1; i--)
     {
-      offset = (2 * i + 0) * sizeof (u32) - f->tail;
+      offset = (2 * i + 0) * sizeof (u32) - f->shr->tail;
       data = (u8 *) (test_data + (2 * i + 0));
       rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
       if (verbose)
@@ -381,7 +381,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
 
   for (i = 0; i < 4; i++)
     {
-      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      offset = (2 * i + 1) * sizeof (u32) - f->shr->tail;
       data = (u8 *) (test_data + (2 * i + 1));
       rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
       if (verbose)
@@ -394,7 +394,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
 	}
     }
 
-  rv = svm_fifo_enqueue_with_offset (f, 8 - f->tail, 21, data);
+  rv = svm_fifo_enqueue_with_offset (f, 8 - f->shr->tail, 21, data);
   SFIFO_TEST ((rv == 0), "ooo enqueued %u", rv);
   SFIFO_TEST ((svm_fifo_n_ooo_segments (f) == 1),
 	      "number of ooo segments %u", svm_fifo_n_ooo_segments (f));
@@ -422,7 +422,7 @@ sfifo_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
 
   for (i = 0; i < 4; i++)
     {
-      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      offset = (2 * i + 1) * sizeof (u32) - f->shr->tail;
       data = (u8 *) (test_data + (2 * i + 1));
       rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
       if (verbose)
@@ -500,8 +500,8 @@ sfifo_test_fifo2 (vlib_main_t * vm)
     {
       tp = vp + i;
       data64 = tp->offset;
-      svm_fifo_enqueue_with_offset (f, tp->offset - f->tail, tp->len,
-				    (u8 *) & data64);
+      svm_fifo_enqueue_with_offset (f, tp->offset - f->shr->tail, tp->len,
+				    (u8 *) &data64);
     }
 
   /* Expected result: one big fat chunk at offset 4 */
@@ -530,8 +530,8 @@ sfifo_test_fifo2 (vlib_main_t * vm)
     {
       tp = &test_data[i];
       data64 = tp->offset;
-      rv = svm_fifo_enqueue_with_offset (f, tp->offset - f->tail, tp->len,
-					 (u8 *) & data64);
+      rv = svm_fifo_enqueue_with_offset (f, tp->offset - f->shr->tail, tp->len,
+					 (u8 *) &data64);
       if (rv)
 	{
 	  clib_warning ("enqueue returned %d", rv);
@@ -704,10 +704,9 @@ sfifo_test_fifo3 (vlib_main_t * vm, unformat_input_t * input)
   for (i = !randomize; i < vec_len (generate); i++)
     {
       tp = generate + i;
-      svm_fifo_enqueue_with_offset (f,
-				    fifo_initial_offset + tp->offset -
-				    f->tail, tp->len,
-				    (u8 *) data_pattern + tp->offset);
+      svm_fifo_enqueue_with_offset (
+	f, fifo_initial_offset + tp->offset - f->shr->tail, tp->len,
+	(u8 *) data_pattern + tp->offset);
     }
 
   /* Add the first segment in order for non random data */
@@ -823,8 +822,8 @@ sfifo_test_fifo4 (vlib_main_t * vm, unformat_input_t * input)
 
   for (i = test_n_bytes - 1; i > 0; i--)
     {
-      rv = svm_fifo_enqueue_with_offset (f, fifo_initial_offset + i - f->tail,
-					 sizeof (u8), &test_data[i]);
+      rv = svm_fifo_enqueue_with_offset (
+	f, fifo_initial_offset + i - f->shr->tail, sizeof (u8), &test_data[i]);
       if (verbose)
 	vlib_cli_output (vm, "add [%d] [%d, %d]", i, i, i + sizeof (u8));
       if (rv)
@@ -1150,7 +1149,8 @@ sfifo_test_fifo7 (vlib_main_t * vm, unformat_input_t * input)
       if (compare_data (data_buf, test_data, 0, n_test_bytes, (u32 *) & j))
 	SFIFO_TEST (0, "[%d] dequeued %u expected %u", j, data_buf[j],
 		    test_data[j]);
-      svm_fifo_init_pointers (f, (~0 - i) % f->size, (~0 - i) % f->size);
+      svm_fifo_init_pointers (f, (~0 - i) % f->shr->size,
+			      (~0 - i) % f->shr->size);
     }
   SFIFO_TEST (1, "passed multiple ooo enqueue/dequeue");
 
@@ -1412,13 +1412,13 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (rv == 2, "should have 2 chunks has %u", rv);
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
-  c = f->head_chunk;
+  c = f->shr->head_chunk;
   SFIFO_TEST (c->start_byte == 0, "head start byte should be %u", 0);
   SFIFO_TEST (c->length == 4096, "head chunk length should be %u", 4096);
-  SFIFO_TEST (f->tail_chunk == 0, "no tail chunk");
+  SFIFO_TEST (f->shr->tail_chunk == 0, "no tail chunk");
   SFIFO_TEST (f->ooo_enq == 0, "should have no ooo enq chunk");
   SFIFO_TEST (f->ooo_deq == 0, "should have no ooo deq chunk");
-  c = f->end_chunk;
+  c = f->shr->end_chunk;
   SFIFO_TEST (c->start_byte == last_start_byte, "end chunk start byte should"
 	      " be %u", last_start_byte);
   SFIFO_TEST (c->length == 4096, "end chunk length should be %u", 4096);
@@ -1438,8 +1438,8 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
     vlib_cli_output (vm, "[%d] dequeued %u expected %u", i, data_buf[i],
 		     test_data[i]);
   SFIFO_TEST ((rv == 0), "dequeued compared to original returned %d", rv);
-  SFIFO_TEST (f->head_chunk == 0, "head chunk should be 0");
-  SFIFO_TEST (f->tail_chunk == 0, "tail chunk should be 0");
+  SFIFO_TEST (f->shr->head_chunk == 0, "head chunk should be 0");
+  SFIFO_TEST (f->shr->tail_chunk == 0, "tail chunk should be 0");
   SFIFO_TEST (f->ooo_deq == 0, "should have no ooo deq chunk");
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
@@ -1461,12 +1461,12 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (rv == 2, "should have %u chunks has %u", 2, rv);
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
-  SFIFO_TEST (f->head_chunk == 0, "should have no head chunk");
+  SFIFO_TEST (f->shr->head_chunk == 0, "should have no head chunk");
   /* When new fifo chunks are allocated, tail is initialized */
-  SFIFO_TEST (f->tail_chunk != 0, "should have no tail chunk");
+  SFIFO_TEST (f->shr->tail_chunk != 0, "should have no tail chunk");
   SFIFO_TEST (f->ooo_enq != 0, "should have an ooo enq chunk");
 
-  c = f->end_chunk;
+  c = f->shr->end_chunk;
   SFIFO_TEST (c->start_byte == last_start_byte,
 	      "end chunk should start at %u", last_start_byte);
   SFIFO_TEST (c->length == 8192, "end chunk length should be %u", 8192);
@@ -1483,9 +1483,9 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (rv == 2, "should have %u chunks has %u", 2, rv);
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
-  SFIFO_TEST (f->head_chunk == 0, "should have no head chunk");
+  SFIFO_TEST (f->shr->head_chunk == 0, "should have no head chunk");
   /* Fifo is full so tail and ooo_enq should be 0 */
-  SFIFO_TEST (f->tail_chunk == 0, "should have no tail chunk");
+  SFIFO_TEST (f->shr->tail_chunk == 0, "should have no tail chunk");
   SFIFO_TEST (f->ooo_enq == 0, "should have no ooo enq chunk");
 
   /*
@@ -1542,8 +1542,8 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   last_start_byte += 8192;
 
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
-  SFIFO_TEST (f->head_chunk == 0, "should have no head chunk");
-  SFIFO_TEST (f->tail_chunk == 0, "should have no tail chunk");
+  SFIFO_TEST (f->shr->head_chunk == 0, "should have no head chunk");
+  SFIFO_TEST (f->shr->tail_chunk == 0, "should have no tail chunk");
 
   /* We don't remove the last chunk even when the fifo goes empty */
   rv = svm_fifo_n_chunks (f);
@@ -1575,12 +1575,12 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (rv == 2, "should have %u chunks has %u", 2, rv);
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
-  SFIFO_TEST (f->head_chunk == 0, "should have no head chunk");
+  SFIFO_TEST (f->shr->head_chunk == 0, "should have no head chunk");
   /* When new fifo chunks are allocated, tail is initialized */
-  SFIFO_TEST (f->tail_chunk != 0, "should have no tail chunk");
+  SFIFO_TEST (f->shr->tail_chunk != 0, "should have no tail chunk");
   SFIFO_TEST (f->ooo_enq != 0, "should have an ooo enq chunk");
 
-  c = f->end_chunk;
+  c = f->shr->end_chunk;
   SFIFO_TEST (c->start_byte == last_start_byte,
 	      "end chunk should start at %u", last_start_byte);
   SFIFO_TEST (c->length == 16384, "end chunk length should be %u", 16384);
@@ -1623,7 +1623,7 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
   last_start_byte += 16384;
-  c = f->end_chunk;
+  c = f->shr->end_chunk;
   SFIFO_TEST (c->start_byte == last_start_byte,
 	      "end chunk should start at %u", last_start_byte);
   SFIFO_TEST (c->length == 4096, "end chunk length should be %u", 4096);
@@ -1647,8 +1647,8 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
 
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
   /* fifo does not end on chunk boundary because of the - 100 */
-  SFIFO_TEST (f->head_chunk != 0, "should have head chunk");
-  SFIFO_TEST (f->tail_chunk != 0, "should have tail chunk");
+  SFIFO_TEST (f->shr->head_chunk != 0, "should have head chunk");
+  SFIFO_TEST (f->shr->tail_chunk != 0, "should have tail chunk");
 
   /*
    * Enqueue and dequeue byte-by-byte ooo
@@ -1673,7 +1673,7 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
   last_start_byte += 4096;
-  c = f->end_chunk;
+  c = f->shr->end_chunk;
   SFIFO_TEST (c->start_byte == last_start_byte,
 	      "end chunk should start at %u", last_start_byte);
   SFIFO_TEST (c->length == 16384, "end chunk length should be %u", 16384);
@@ -1688,8 +1688,8 @@ sfifo_test_fifo_grow (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST ((rv == fifo_size), "all bytes should be dropped %u", rv);
 
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
-  SFIFO_TEST (f->head_chunk != 0, "should have head chunk");
-  SFIFO_TEST (f->tail_chunk != 0, "should have tail chunk");
+  SFIFO_TEST (f->shr->head_chunk != 0, "should have head chunk");
+  SFIFO_TEST (f->shr->tail_chunk != 0, "should have tail chunk");
 
   /* We don't remove the last chunk even when the fifo goes empty */
   rv = svm_fifo_n_chunks (f);
@@ -1941,7 +1941,7 @@ sfifo_test_fifo_indirect (vlib_main_t * vm, unformat_input_t * input)
   svm_fifo_set_size (f, fifo_size);
   validate_test_and_buf_vecs (&test_data, &data_buf, fifo_size);
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
   SFIFO_TEST (c->next == 0, "no next");
 
   svm_fifo_fill_chunk_list (f);
@@ -1958,7 +1958,7 @@ sfifo_test_fifo_indirect (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (svm_fifo_is_sane (f), "fifo should be sane");
 
   c = svm_fifo_tail_chunk (f);
-  SFIFO_TEST (c == f->end_chunk, "tail is end chunk");
+  SFIFO_TEST (c == f->shr->end_chunk, "tail is end chunk");
 
   /* Initialize head chunk */
   rv = svm_fifo_max_read_chunk (f);
@@ -1972,7 +1972,7 @@ sfifo_test_fifo_indirect (vlib_main_t * vm, unformat_input_t * input)
   SFIFO_TEST (rv == 4096, "dequeue should work");
 
   c = svm_fifo_head_chunk (f);
-  SFIFO_TEST (c == f->end_chunk, "head chunk should be last");
+  SFIFO_TEST (c == f->shr->end_chunk, "head chunk should be last");
 
   rv = svm_fifo_max_read_chunk (f);
   SFIFO_TEST (rv == 0, "max read chunk %u", rv);
@@ -2409,13 +2409,13 @@ sfifo_test_fifo_segment_slave (int verbose)
       svm_fifo_dequeue (f, vec_len (retrieved_data), retrieved_data);
       if (memcmp (retrieved_data, test_data, vec_len (retrieved_data)))
 	{
-	  result = (u32 *) f->head_chunk->data;
+	  result = (u32 *) f->shr->head_chunk->data;
 	  *result = 1;
 	  _exit (0);
 	}
     }
 
-  result = (u32 *) f->head_chunk->data;
+  result = (u32 *) f->shr->head_chunk->data;
   *result = 0;
 
   vec_free (test_data);
@@ -2469,7 +2469,7 @@ sfifo_test_fifo_segment_master_slave (int verbose)
 
   usleep (1e3);
 
-  result = (u32 *) f->head_chunk->data;
+  result = (u32 *) f->shr->head_chunk->data;
   SFIFO_TEST (*result == 0, "slave reported no error");
 
   vec_free (a->new_segment_indices);
@@ -2597,7 +2597,7 @@ sfifo_test_fifo_segment_prealloc (int verbose)
   rv = fifo_segment_num_free_fifos (fs);
   SFIFO_TEST (rv == 50, "prealloc fifo hdrs expected %u is %u", 50, rv);
   rv = fifo_segment_free_bytes (fs);
-  free_space -= sizeof (svm_fifo_t) * 50;
+  free_space -= sizeof (svm_fifo_shared_t) * 50;
   /* Memory alloc alignment accounts for the difference */
   SFIFO_TEST (approx_leq (free_space, rv, 128), "free space expected %u is %u",
 	      free_space, rv);
diff --git a/src/svm/fifo_segment.c b/src/svm/fifo_segment.c
index b4c3cbe6c6d..19fd0520666 100644
--- a/src/svm/fifo_segment.c
+++ b/src/svm/fifo_segment.c
@@ -14,6 +14,7 @@
  */
 
 #include <svm/fifo_segment.h>
+#include <vppinfra/mem.h>
 
 static inline void *
 fsh_alloc_aligned (fifo_segment_header_t *fsh, uword size, uword align)
@@ -239,7 +240,7 @@ fss_fl_chunk_bytes_sub (fifo_segment_slice_t * fss, uword size)
 int
 fifo_segment_init (fifo_segment_t * fs)
 {
-  u32 align = 8, offset = 2 * 4096, slices_sz;
+  u32 align = 8, offset = 2 * 4096, slices_sz, i;
   uword max_fifo, seg_start, seg_sz;
   fifo_segment_header_t *fsh;
   ssvm_shared_header_t *sh;
@@ -270,6 +271,11 @@ fifo_segment_init (fifo_segment_t * fs)
   fs->max_byte_index = fsh->max_byte_index;
   fs->h = sh->opaque[0] = fsh;
 
+  vec_validate (fs->slices, fs->n_slices - 1);
+  for (i = 0; i < fs->n_slices; i++)
+    fs->slices[i].fifos =
+      clib_mem_bulk_init (sizeof (svm_fifo_t), CLIB_CACHE_LINE_BYTES, 32);
+
   sh->ready = 1;
   return (0);
 }
@@ -343,6 +349,9 @@ fifo_segment_attach (fifo_segment_main_t * sm, fifo_segment_create_args_t * a)
     goto done;
 
   fs->max_byte_index = fsh->max_byte_index;
+  vec_validate (fs->slices, 0);
+  fs->slices[0].fifos =
+    clib_mem_bulk_init (sizeof (svm_fifo_t), CLIB_CACHE_LINE_BYTES, 32);
 
 done:
   vec_add1 (a->new_segment_indices, fs - sm->segments);
@@ -352,6 +361,7 @@ done:
 void
 fifo_segment_delete (fifo_segment_main_t * sm, fifo_segment_t * s)
 {
+  fifo_segment_cleanup (s);
   ssvm_delete (&s->ssvm);
   clib_memset (s, 0xfe, sizeof (*s));
   pool_put (sm->segments, s);
@@ -478,7 +488,7 @@ static int
 fsh_try_alloc_fifo_hdr_batch (fifo_segment_header_t * fsh,
 			      fifo_segment_slice_t * fss, u32 batch_size)
 {
-  svm_fifo_t *f;
+  svm_fifo_shared_t *f;
   uword size;
   u8 *fmem;
   int i;
@@ -494,7 +504,7 @@ fsh_try_alloc_fifo_hdr_batch (fifo_segment_header_t * fsh,
   /* Carve fifo hdr space */
   for (i = 0; i < batch_size; i++)
     {
-      f = (svm_fifo_t *) fmem;
+      f = (svm_fifo_shared_t *) fmem;
       memset (f, 0, sizeof (*f));
       f->next = fss->free_fifos;
       fss->free_fifos = f;
@@ -555,11 +565,10 @@ fs_try_alloc_fifo_batch (fifo_segment_header_t * fsh,
   return fsh_try_alloc_chunk_batch (fsh, fss, fl_index, batch_size);
 }
 
-static svm_fifo_t *
-fsh_try_alloc_fifo_hdr (fifo_segment_header_t * fsh,
-			fifo_segment_slice_t * fss)
+static svm_fifo_shared_t *
+fsh_try_alloc_fifo_hdr (fifo_segment_header_t *fsh, fifo_segment_slice_t *fss)
 {
-  svm_fifo_t *f;
+  svm_fifo_shared_t *f;
 
   if (!fss->free_fifos)
     {
@@ -642,40 +651,41 @@ done:
  * - single fifo allocation
  * - grab multiple fifo chunks from freelists
  */
-static svm_fifo_t *
-fs_try_alloc_fifo (fifo_segment_header_t * fsh, fifo_segment_slice_t * fss,
-		   u32 data_bytes)
+static svm_fifo_shared_t *
+fs_try_alloc_fifo (fifo_segment_header_t *fsh, u32 slice_index, u32 data_bytes)
 {
+  fifo_segment_slice_t *fss;
   u32 fl_index, min_size;
   svm_fifo_chunk_t *c;
-  svm_fifo_t *f = 0;
+  svm_fifo_shared_t *sf = 0;
 
+  fss = fsh_slice_get (fsh, slice_index);
   min_size = clib_max ((fsh->pct_first_alloc * data_bytes) / 100, 4096);
   fl_index = fs_freelist_for_size (min_size);
 
   if (!fss_chunk_fl_index_is_valid (fss, fl_index))
     return 0;
 
-  f = fsh_try_alloc_fifo_hdr (fsh, fss);
-  if (!f)
+  sf = fsh_try_alloc_fifo_hdr (fsh, fss);
+  if (!sf)
     return 0;
 
   c = fsh_try_alloc_chunk (fsh, fss, min_size);
   if (!c)
     {
-      f->next = fss->free_fifos;
-      fss->free_fifos = f;
+      sf->next = fss->free_fifos;
+      fss->free_fifos = sf;
       return 0;
     }
 
-  f->start_chunk = c;
+  sf->start_chunk = c;
   while (c->next)
     c = c->next;
-  f->end_chunk = c;
-  f->size = data_bytes;
-  f->fs_hdr = fsh;
+  sf->end_chunk = c;
+  sf->size = data_bytes;
+  sf->slice_index = slice_index;
 
-  return f;
+  return sf;
 }
 
 svm_fifo_chunk_t *
@@ -720,6 +730,36 @@ fsh_collect_chunks (fifo_segment_header_t * fsh, u32 slice_index,
   fsh_slice_collect_chunks (fsh, fss, c);
 }
 
+svm_fifo_t *
+fs_fifo_alloc (fifo_segment_t *fs, u32 slice_index)
+{
+  fifo_slice_private_t *pfss = &fs->slices[slice_index];
+  svm_fifo_t *f;
+
+  f = clib_mem_bulk_alloc (pfss->fifos);
+  clib_memset (f, 0, sizeof (*f));
+  return f;
+}
+
+void
+fs_fifo_free (fifo_segment_t *fs, svm_fifo_t *f)
+{
+  u32 slice_index = f->shr->slice_index;
+  fifo_slice_private_t *pfss;
+
+  pfss = &fs->slices[slice_index];
+  clib_mem_bulk_free (pfss->fifos, f);
+}
+
+void
+fifo_segment_cleanup (fifo_segment_t *fs)
+{
+  int slice_index;
+
+  for (slice_index = 0; slice_index < fs->n_slices; slice_index++)
+    clib_mem_bulk_destroy (fs->slices[slice_index].fifos);
+}
+
 /**
  * Allocate fifo in fifo segment
  */
@@ -729,6 +769,7 @@ fifo_segment_alloc_fifo_w_slice (fifo_segment_t * fs, u32 slice_index,
 {
   fifo_segment_header_t *fsh = fs->h;
   fifo_segment_slice_t *fss;
+  svm_fifo_shared_t *sf;
   svm_fifo_t *f = 0;
 
   ASSERT (slice_index < fs->n_slices);
@@ -736,15 +777,18 @@ fifo_segment_alloc_fifo_w_slice (fifo_segment_t * fs, u32 slice_index,
   if (PREDICT_FALSE (data_bytes > 1 << fsh->max_log2_fifo_size))
     return 0;
 
-  fss = fsh_slice_get (fsh, slice_index);
-  f = fs_try_alloc_fifo (fsh, fss, data_bytes);
-  if (!f)
+  sf = fs_try_alloc_fifo (fsh, slice_index, data_bytes);
+  if (!sf)
     goto done;
 
-  f->slice_index = slice_index;
+  f = fs_fifo_alloc (fs, slice_index);
+  f->fs_hdr = fsh;
+  f->shr = sf;
 
   svm_fifo_init (f, data_bytes);
 
+  fss = fsh_slice_get (fsh, slice_index);
+
   /* If rx fifo type add to active fifos list. When cleaning up segment,
    * we need a list of active sessions that should be disconnected. Since
    * both rx and tx fifos keep pointers to the session, it's enough to track
@@ -762,6 +806,19 @@ done:
   return (f);
 }
 
+svm_fifo_t *
+fifo_segment_alloc_fifo_w_shared (fifo_segment_t *fs, svm_fifo_shared_t *sf)
+{
+  svm_fifo_t *f = fs_fifo_alloc (fs, 0);
+  f->fs_hdr = fs->h;
+  f->shr = sf;
+
+  f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
+  f->segment_index = SVM_FIFO_INVALID_INDEX;
+  f->refcnt = 1;
+  return f;
+}
+
 /**
  * Free fifo allocated in fifo segment
  */
@@ -770,13 +827,35 @@ fifo_segment_free_fifo (fifo_segment_t * fs, svm_fifo_t * f)
 {
   fifo_segment_header_t *fsh = fs->h;
   fifo_segment_slice_t *fss;
+  svm_fifo_shared_t *sf;
 
   ASSERT (f->refcnt > 0);
 
   if (--f->refcnt > 0)
     return;
 
-  fss = fsh_slice_get (fsh, f->slice_index);
+  /*
+   * Cleanup shared state
+   */
+
+  sf = f->shr;
+  fss = fsh_slice_get (fsh, sf->slice_index);
+
+  /* Free fifo chunks */
+  fsh_slice_collect_chunks (fsh, fss, sf->start_chunk);
+
+  sf->start_chunk = sf->end_chunk = 0;
+  sf->head_chunk = sf->tail_chunk = 0;
+
+  /* Add to free list */
+  sf->next = fss->free_fifos;
+  fss->free_fifos = sf;
+
+  fss->virtual_mem -= svm_fifo_size (f);
+
+  /*
+   *  Cleanup private state
+   */
 
   /* Remove from active list. Only rx fifos are tracked */
   if (f->flags & SVM_FIFO_F_LL_TRACKED)
@@ -785,28 +864,19 @@ fifo_segment_free_fifo (fifo_segment_t * fs, svm_fifo_t * f)
       f->flags &= ~SVM_FIFO_F_LL_TRACKED;
     }
 
-  /* Free fifo chunks */
-  fsh_slice_collect_chunks (fsh, fss, f->start_chunk);
-
-  f->start_chunk = f->end_chunk = 0;
-  f->head_chunk = f->tail_chunk = f->ooo_enq = f->ooo_deq = 0;
-
-  /* not allocated on segment heap */
   svm_fifo_free_chunk_lookup (f);
   svm_fifo_free_ooo_data (f);
 
   if (CLIB_DEBUG)
     {
-      f->master_session_index = ~0;
+      sf->master_session_index = ~0;
       f->master_thread_index = ~0;
     }
 
-  fss->virtual_mem -= svm_fifo_size (f);
-
-  /* Add to free list */
-  f->next = fss->free_fifos;
+  f->ooo_enq = f->ooo_deq = 0;
   f->prev = 0;
-  fss->free_fifos = f;
+
+  fs_fifo_free (fs, f);
 
   fsh_active_fifos_update (fsh, -1);
 }
@@ -820,12 +890,12 @@ fifo_segment_detach_fifo (fifo_segment_t * fs, svm_fifo_t * f)
 
   ASSERT (f->refcnt == 1);
 
-  fss = fsh_slice_get (fs->h, f->slice_index);
+  fss = fsh_slice_get (fs->h, f->shr->slice_index);
   fss->virtual_mem -= svm_fifo_size (f);
   if (f->flags & SVM_FIFO_F_LL_TRACKED)
     fss_fifo_del_active_list (fss, f);
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
   while (c)
     {
       fl_index = fs_freelist_for_size (c->length);
@@ -842,13 +912,13 @@ fifo_segment_attach_fifo (fifo_segment_t * fs, svm_fifo_t * f,
   svm_fifo_chunk_t *c;
   u32 fl_index;
 
-  f->slice_index = slice_index;
-  fss = fsh_slice_get (fs->h, f->slice_index);
+  f->shr->slice_index = slice_index;
+  fss = fsh_slice_get (fs->h, f->shr->slice_index);
   fss->virtual_mem += svm_fifo_size (f);
   if (f->flags & SVM_FIFO_F_LL_TRACKED)
     fss_fifo_add_active_list (fss, f);
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
   while (c)
     {
       fl_index = fs_freelist_for_size (c->length);
@@ -966,7 +1036,7 @@ fifo_segment_num_fifos (fifo_segment_t * fs)
 static u32
 fs_slice_num_free_fifos (fifo_segment_slice_t * fss)
 {
-  svm_fifo_t *f;
+  svm_fifo_shared_t *f;
   u32 count = 0;
 
   f = fss->free_fifos;
diff --git a/src/svm/fifo_segment.h b/src/svm/fifo_segment.h
index 39c94548636..006ffc40f63 100644
--- a/src/svm/fifo_segment.h
+++ b/src/svm/fifo_segment.h
@@ -69,6 +69,7 @@ typedef struct
   fifo_segment_header_t *h;	/**< fifo segment data */
   uword max_byte_index;
   u8 n_slices;			/**< number of fifo segment slices */
+  fifo_slice_private_t *slices; /**< private slice information */
 } fifo_segment_t;
 
 typedef struct
@@ -95,6 +96,7 @@ int fifo_segment_create (fifo_segment_main_t * sm,
 int fifo_segment_attach (fifo_segment_main_t * sm,
 			 fifo_segment_create_args_t * a);
 void fifo_segment_delete (fifo_segment_main_t * sm, fifo_segment_t * fs);
+void fifo_segment_cleanup (fifo_segment_t *fs);
 fifo_segment_t *fifo_segment_get_segment (fifo_segment_main_t * sm,
 					  u32 fs_index);
 u32 fifo_segment_index (fifo_segment_main_t * sm, fifo_segment_t * fs);
@@ -112,6 +114,8 @@ svm_fifo_t *fifo_segment_alloc_fifo_w_slice (fifo_segment_t * fs,
 					     u32 slice_index,
 					     u32 data_bytes,
 					     fifo_segment_ftype_t ftype);
+svm_fifo_t *fifo_segment_alloc_fifo_w_shared (fifo_segment_t *fs,
+					      svm_fifo_shared_t *sf);
 
 /**
  * Free fifo allocated in fifo segment
diff --git a/src/svm/fifo_types.h b/src/svm/fifo_types.h
index e839e7eaab7..434b2c38b4c 100644
--- a/src/svm/fifo_types.h
+++ b/src/svm/fifo_types.h
@@ -59,59 +59,65 @@ typedef struct
   u32 action;
 } svm_fifo_trace_elem_t;
 
-typedef struct _svm_fifo
+typedef struct svm_fifo_shr_
 {
-  CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
-  fifo_segment_header_t *fs_hdr;/**< fifo segment header for fifo */
+  CLIB_CACHE_LINE_ALIGN_MARK (shared);
   svm_fifo_chunk_t *start_chunk;/**< first chunk in fifo chunk list */
   svm_fifo_chunk_t *end_chunk;	/**< end chunk in fifo chunk list */
+  volatile u32 has_event;	/**< non-zero if deq event exists */
   u32 min_alloc;		/**< min chunk alloc if space available */
   u32 size;			/**< size of the fifo in bytes */
-  u8 flags;			/**< fifo flags */
-  u8 slice_index;		/**< segment slice for fifo */
-
-    CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
-  volatile u32 has_event;	/**< non-zero if deq event exists */
   u32 master_session_index;	/**< session layer session index */
   u32 client_session_index;	/**< app session index */
-  u8 master_thread_index;	/**< session layer thread index */
-  u8 client_thread_index;	/**< app worker index */
-  i8 refcnt;			/**< reference count  */
-  u32 segment_manager;		/**< session layer segment manager index */
-  u32 segment_index;		/**< segment index in segment manager */
-  struct _svm_fifo *next;	/**< next in freelist/active chain */
-  struct _svm_fifo *prev;	/**< prev in active chain */
-
-    CLIB_CACHE_LINE_ALIGN_MARK (consumer);
-  rb_tree_t ooo_deq_lookup;	/**< rbtree for ooo deq chunk lookup */
+  u8 slice_index;		/**< segment slice for fifo */
+  struct svm_fifo_shr_ *next;	/**< next in freelist/active chain */
+
+  CLIB_CACHE_LINE_ALIGN_MARK (consumer);
   svm_fifo_chunk_t *head_chunk;	/**< tracks chunk where head lands */
-  svm_fifo_chunk_t *ooo_deq;	/**< last chunk used for ooo dequeue */
   u32 head;			/**< fifo head position/byte */
   volatile u32 want_deq_ntf;	/**< producer wants nudge */
   volatile u32 has_deq_ntf;
 
-    CLIB_CACHE_LINE_ALIGN_MARK (producer);
-  rb_tree_t ooo_enq_lookup;	/**< rbtree for ooo enq chunk lookup */
+  CLIB_CACHE_LINE_ALIGN_MARK (producer);
   u32 tail;			/**< fifo tail position/byte */
-  u32 ooos_list_head;		/**< Head of out-of-order linked-list */
   svm_fifo_chunk_t *tail_chunk;	/**< tracks chunk where tail lands */
+  volatile u8 n_subscribers;	/**< Number of subscribers for io events */
+  u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
+} svm_fifo_shared_t;
+
+typedef struct _svm_fifo
+{
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline);
+  svm_fifo_shared_t *shr;	 /**< shared fifo in fifo segment memory */
+  fifo_segment_header_t *fs_hdr; /**< fifo segment header for fifo */
+  rb_tree_t ooo_enq_lookup;	 /**< rbtree for ooo enq chunk lookup */
+  rb_tree_t ooo_deq_lookup;	 /**< rbtree for ooo deq chunk lookup */
+  svm_fifo_chunk_t *ooo_deq;	 /**< last chunk used for ooo dequeue */
   svm_fifo_chunk_t *ooo_enq;	/**< last chunk used for ooo enqueue */
   ooo_segment_t *ooo_segments;	/**< Pool of ooo segments */
+  u32 ooos_list_head;		/**< Head of out-of-order linked-list */
   u32 ooos_newest;		/**< Last segment to have been updated */
-  volatile u8 n_subscribers;	/**< Number of subscribers for io events */
-  u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
+
+  u8 flags;		  /**< fifo flags */
+  u8 master_thread_index; /**< session layer thread index */
+  u8 client_thread_index; /**< app worker index */
+  i8 refcnt;		  /**< reference count  */
+  u32 segment_manager;	  /**< session layer segment manager index */
+  u32 segment_index;	  /**< segment index in segment manager */
+
+  struct _svm_fifo *next; /**< prev in active chain */
+  struct _svm_fifo *prev; /**< prev in active chain */
 
 #if SVM_FIFO_TRACE
   svm_fifo_trace_elem_t *trace;
 #endif
-
 } svm_fifo_t;
 
 typedef struct fifo_segment_slice_
 {
   svm_fifo_chunk_t *free_chunks[FS_CHUNK_VEC_LEN]; /**< Free chunks by size */
   svm_fifo_t *fifos;			/**< Linked list of active RX fifos */
-  svm_fifo_t *free_fifos;		/**< Freelists by fifo size  */
+  svm_fifo_shared_t *free_fifos;	/**< Freelists of fifo shared hdrs  */
   uword n_fl_chunk_bytes;		/**< Chunk bytes on freelist */
   uword virtual_mem;			/**< Slice sum of all fifo sizes */
   u32 num_chunks[FS_CHUNK_VEC_LEN];	/**< Allocated chunks by chunk size */
@@ -120,6 +126,12 @@ typedef struct fifo_segment_slice_
   u32 chunk_lock;
 } fifo_segment_slice_t;
 
+typedef struct fifo_slice_private_
+{
+  clib_mem_bulk_handle_t fifos; /**< Bulk fifo allocator */
+  uword virtual_mem;		/**< Slice sum of all fifo sizes */
+} fifo_slice_private_t;
+
 struct fifo_segment_header_
 {
   uword n_cached_bytes;			/**< Cached bytes */
diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
index 0c08dba7aa2..2f910e0b95f 100644
--- a/src/svm/svm_fifo.c
+++ b/src/svm/svm_fifo.c
@@ -348,7 +348,7 @@ ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued, u32 * tail)
 	}
     }
 
-  ASSERT (bytes <= f->size);
+  ASSERT (bytes <= f->shr->size);
   return bytes;
 }
 
@@ -372,23 +372,23 @@ svm_fifo_init (svm_fifo_t * f, u32 size)
   svm_fifo_chunk_t *c, *prev;
   u32 min_alloc;
 
-  f->size = size;
+  f->shr->size = size;
   f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
   f->segment_index = SVM_FIFO_INVALID_INDEX;
   f->refcnt = 1;
-  f->head = f->tail = f->flags = 0;
-  f->head_chunk = f->tail_chunk = f->start_chunk;
+  f->shr->head = f->shr->tail = f->flags = 0;
+  f->shr->head_chunk = f->shr->tail_chunk = f->shr->start_chunk;
   f->ooo_deq = f->ooo_enq = 0;
 
   min_alloc = size > 32 << 10 ? size >> 3 : 4096;
   min_alloc = clib_min (min_alloc, 64 << 10);
-  f->min_alloc = min_alloc;
+  f->shr->min_alloc = min_alloc;
 
   /*
    * Initialize chunks
    */
-  f->start_chunk->start_byte = 0;
-  prev = f->start_chunk;
+  f->shr->start_chunk->start_byte = 0;
+  prev = f->shr->start_chunk;
   prev->enq_rb_index = prev->deq_rb_index = RBTREE_TNIL_INDEX;
   c = prev->next;
 
@@ -447,7 +447,7 @@ svm_fifo_alloc (u32 data_size_in_bytes)
   c->length = data_size_in_bytes;
   c->enq_rb_index = RBTREE_TNIL_INDEX;
   c->deq_rb_index = RBTREE_TNIL_INDEX;
-  f->start_chunk = f->end_chunk = c;
+  f->shr->start_chunk = f->shr->end_chunk = c;
 
   return f;
 }
@@ -486,7 +486,7 @@ svm_fifo_find_chunk (svm_fifo_t * f, u32 pos)
 {
   svm_fifo_chunk_t *c;
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
   while (c && !f_chunk_includes_pos (c, pos))
     c = c->next;
 
@@ -513,16 +513,17 @@ svm_fifo_max_read_chunk (svm_fifo_t * f)
   u32 head, tail, end_chunk;
 
   f_load_head_tail_cons (f, &head, &tail);
-  ASSERT (!f->head_chunk || f_chunk_includes_pos (f->head_chunk, head));
+  ASSERT (!f->shr->head_chunk ||
+	  f_chunk_includes_pos (f->shr->head_chunk, head));
 
-  if (!f->head_chunk)
+  if (!f->shr->head_chunk)
     {
-      f->head_chunk = svm_fifo_find_chunk (f, head);
-      if (PREDICT_FALSE (!f->head_chunk))
+      f->shr->head_chunk = svm_fifo_find_chunk (f, head);
+      if (PREDICT_FALSE (!f->shr->head_chunk))
 	return 0;
     }
 
-  end_chunk = f_chunk_end (f->head_chunk);
+  end_chunk = f_chunk_end (f->shr->head_chunk);
 
   return f_pos_lt (end_chunk, tail) ? end_chunk - head : tail - head;
 }
@@ -533,9 +534,10 @@ svm_fifo_max_write_chunk (svm_fifo_t * f)
   u32 head, tail;
 
   f_load_head_tail_prod (f, &head, &tail);
-  ASSERT (!f->tail_chunk || f_chunk_includes_pos (f->tail_chunk, tail));
+  ASSERT (!f->shr->tail_chunk ||
+	  f_chunk_includes_pos (f->shr->tail_chunk, tail));
 
-  return f->tail_chunk ? f_chunk_end (f->tail_chunk) - tail : 0;
+  return f->shr->tail_chunk ? f_chunk_end (f->shr->tail_chunk) - tail : 0;
 }
 
 static rb_node_t *
@@ -605,13 +607,13 @@ f_update_ooo_enq (svm_fifo_t * f, u32 start_pos, u32 end_pos)
   /* Use linear search if rbtree is not initialized */
   if (PREDICT_FALSE (!rb_tree_is_init (rt)))
     {
-      f->ooo_enq = svm_fifo_find_next_chunk (f, f->tail_chunk, start_pos);
+      f->ooo_enq = svm_fifo_find_next_chunk (f, f->shr->tail_chunk, start_pos);
       return;
     }
 
   if (rt->root == RBTREE_TNIL_INDEX)
     {
-      c = f->tail_chunk;
+      c = f->shr->tail_chunk;
       ASSERT (c->enq_rb_index == RBTREE_TNIL_INDEX);
       c->enq_rb_index = rb_tree_add_custom (rt, c->start_byte,
 					    pointer_to_uword (c), f_pos_lt);
@@ -660,7 +662,7 @@ f_update_ooo_deq (svm_fifo_t * f, u32 start_pos, u32 end_pos)
 
   if (rt->root == RBTREE_TNIL_INDEX)
     {
-      c = f->start_chunk;
+      c = f->shr->start_chunk;
       ASSERT (c->deq_rb_index == RBTREE_TNIL_INDEX);
       c->deq_rb_index = rb_tree_add_custom (rt, c->start_byte,
 					    pointer_to_uword (c), f_pos_lt);
@@ -778,14 +780,14 @@ svm_fifo_overwrite_head (svm_fifo_t * f, u8 * src, u32 len)
   u32 head, tail, head_idx;
   svm_fifo_chunk_t *c;
 
-  ASSERT (len <= f->size);
+  ASSERT (len <= f->shr->size);
 
   f_load_head_tail_cons (f, &head, &tail);
 
-  if (!f->head_chunk)
-    f->head_chunk = svm_fifo_find_chunk (f, head);
+  if (!f->shr->head_chunk)
+    f->shr->head_chunk = svm_fifo_find_chunk (f, head);
 
-  c = f->head_chunk;
+  c = f->shr->head_chunk;
   head_idx = head - c->start_byte;
   n_chunk = c->length - head_idx;
   if (len <= n_chunk)
@@ -804,17 +806,17 @@ f_try_chunk_alloc (svm_fifo_t * f, u32 head, u32 tail, u32 len)
   svm_fifo_chunk_t *c, *cur, *prev;
   u32 alloc_size, free_alloced;
 
-  free_alloced = f_chunk_end (f->end_chunk) - tail;
+  free_alloced = f_chunk_end (f->shr->end_chunk) - tail;
 
-  alloc_size = clib_min (f->min_alloc, f->size - (tail - head));
+  alloc_size = clib_min (f->shr->min_alloc, f->shr->size - (tail - head));
   alloc_size = clib_max (alloc_size, len - free_alloced);
 
-  c = fsh_alloc_chunk (f->fs_hdr, f->slice_index, alloc_size);
+  c = fsh_alloc_chunk (f->fs_hdr, f->shr->slice_index, alloc_size);
   if (PREDICT_FALSE (!c))
     return -1;
 
   cur = c;
-  prev = f->end_chunk;
+  prev = f->shr->end_chunk;
 
   while (cur)
     {
@@ -827,11 +829,11 @@ f_try_chunk_alloc (svm_fifo_t * f, u32 head, u32 tail, u32 len)
     }
 
   prev->next = 0;
-  f->end_chunk->next = c;
-  f->end_chunk = prev;
+  f->shr->end_chunk->next = c;
+  f->shr->end_chunk = prev;
 
-  if (!f->tail_chunk)
-    f->tail_chunk = c;
+  if (!f->shr->tail_chunk)
+    f->shr->tail_chunk = c;
 
   return 0;
 }
@@ -855,19 +857,20 @@ svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src)
   /* number of bytes we're going to copy */
   len = clib_min (free_count, len);
 
-  if (f_pos_gt (tail + len, f_chunk_end (f->end_chunk)))
+  if (f_pos_gt (tail + len, f_chunk_end (f->shr->end_chunk)))
     {
       if (PREDICT_FALSE (f_try_chunk_alloc (f, head, tail, len)))
 	{
-	  len = f_chunk_end (f->end_chunk) - tail;
+	  len = f_chunk_end (f->shr->end_chunk) - tail;
 	  if (!len)
 	    return SVM_FIFO_EGROW;
 	}
     }
 
-  old_tail_c = f->tail_chunk;
+  old_tail_c = f->shr->tail_chunk;
 
-  svm_fifo_copy_to_chunk (f, f->tail_chunk, tail, src, len, &f->tail_chunk);
+  svm_fifo_copy_to_chunk (f, f->shr->tail_chunk, tail, src, len,
+			  &f->shr->tail_chunk);
   tail = tail + len;
 
   svm_fifo_trace_add (f, head, len, 2);
@@ -877,12 +880,12 @@ svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src)
     {
       len += ooo_segment_try_collect (f, len, &tail);
       /* Tail chunk might've changed even if nothing was collected */
-      f->tail_chunk = f_lookup_clear_enq_chunks (f, old_tail_c, tail);
+      f->shr->tail_chunk = f_lookup_clear_enq_chunks (f, old_tail_c, tail);
       f->ooo_enq = 0;
     }
 
   /* store-rel: producer owned index (paired with load-acq in consumer) */
-  clib_atomic_store_rel_n (&f->tail, tail);
+  clib_atomic_store_rel_n (&f->shr->tail, tail);
 
   return len;
 }
@@ -911,7 +914,7 @@ svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 len, u8 * src)
 
   enq_pos = tail + offset;
 
-  if (f_pos_gt (enq_pos + len, f_chunk_end (f->end_chunk)))
+  if (f_pos_gt (enq_pos + len, f_chunk_end (f->shr->end_chunk)))
     {
       if (PREDICT_FALSE (f_try_chunk_alloc (f, head, tail, offset + len)))
 	return SVM_FIFO_EGROW;
@@ -938,21 +941,23 @@ svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
 
   ASSERT (len <= svm_fifo_max_enqueue_prod (f));
   /* load-relaxed: producer owned index */
-  tail = f->tail;
+  tail = f->shr->tail;
   tail = tail + len;
 
   if (rb_tree_is_init (&f->ooo_enq_lookup))
     {
-      f->tail_chunk = f_lookup_clear_enq_chunks (f, f->tail_chunk, tail);
+      f->shr->tail_chunk =
+	f_lookup_clear_enq_chunks (f, f->shr->tail_chunk, tail);
       f->ooo_enq = 0;
     }
   else
     {
-      f->tail_chunk = svm_fifo_find_next_chunk (f, f->tail_chunk, tail);
+      f->shr->tail_chunk =
+	svm_fifo_find_next_chunk (f, f->shr->tail_chunk, tail);
     }
 
   /* store-rel: producer owned index (paired with load-acq in consumer) */
-  clib_atomic_store_rel_n (&f->tail, tail);
+  clib_atomic_store_rel_n (&f->shr->tail, tail);
 }
 
 int
@@ -975,14 +980,14 @@ svm_fifo_enqueue_segments (svm_fifo_t * f, const svm_fifo_seg_t segs[],
   for (i = 0; i < n_segs; i++)
     len += segs[i].len;
 
-  old_tail_c = f->tail_chunk;
+  old_tail_c = f->shr->tail_chunk;
 
   if (!allow_partial)
     {
       if (PREDICT_FALSE (free_count < len))
 	return SVM_FIFO_EFULL;
 
-      if (f_pos_gt (tail + len, f_chunk_end (f->end_chunk)))
+      if (f_pos_gt (tail + len, f_chunk_end (f->shr->end_chunk)))
 	{
 	  if (PREDICT_FALSE (f_try_chunk_alloc (f, head, tail, len)))
 	    return SVM_FIFO_EGROW;
@@ -990,8 +995,8 @@ svm_fifo_enqueue_segments (svm_fifo_t * f, const svm_fifo_seg_t segs[],
 
       for (i = 0; i < n_segs; i++)
 	{
-	  svm_fifo_copy_to_chunk (f, f->tail_chunk, tail, segs[i].data,
-				  segs[i].len, &f->tail_chunk);
+	  svm_fifo_copy_to_chunk (f, f->shr->tail_chunk, tail, segs[i].data,
+				  segs[i].len, &f->shr->tail_chunk);
 	  tail += segs[i].len;
 	}
     }
@@ -999,11 +1004,11 @@ svm_fifo_enqueue_segments (svm_fifo_t * f, const svm_fifo_seg_t segs[],
     {
       len = clib_min (free_count, len);
 
-      if (f_pos_gt (tail + len, f_chunk_end (f->end_chunk)))
+      if (f_pos_gt (tail + len, f_chunk_end (f->shr->end_chunk)))
 	{
 	  if (PREDICT_FALSE (f_try_chunk_alloc (f, head, tail, len)))
 	    {
-	      len = f_chunk_end (f->end_chunk) - tail;
+	      len = f_chunk_end (f->shr->end_chunk) - tail;
 	      if (!len)
 		return SVM_FIFO_EGROW;
 	    }
@@ -1013,8 +1018,8 @@ svm_fifo_enqueue_segments (svm_fifo_t * f, const svm_fifo_seg_t segs[],
       while (len)
 	{
 	  u32 to_copy = clib_min (segs[i].len, len);
-	  svm_fifo_copy_to_chunk (f, f->tail_chunk, tail, segs[i].data,
-				  to_copy, &f->tail_chunk);
+	  svm_fifo_copy_to_chunk (f, f->shr->tail_chunk, tail, segs[i].data,
+				  to_copy, &f->shr->tail_chunk);
 	  len -= to_copy;
 	  tail += to_copy;
 	  i++;
@@ -1026,12 +1031,12 @@ svm_fifo_enqueue_segments (svm_fifo_t * f, const svm_fifo_seg_t segs[],
     {
       len += ooo_segment_try_collect (f, len, &tail);
       /* Tail chunk might've changed even if nothing was collected */
-      f->tail_chunk = f_lookup_clear_enq_chunks (f, old_tail_c, tail);
+      f->shr->tail_chunk = f_lookup_clear_enq_chunks (f, old_tail_c, tail);
       f->ooo_enq = 0;
     }
 
   /* store-rel: producer owned index (paired with load-acq in consumer) */
-  clib_atomic_store_rel_n (&f->tail, tail);
+  clib_atomic_store_rel_n (&f->shr->tail, tail);
 
   return len;
 }
@@ -1043,12 +1048,12 @@ f_unlink_chunks (svm_fifo_t * f, u32 end_pos, u8 maybe_ooo)
   rb_tree_t *rt;
   rb_node_t *n;
 
-  ASSERT (!f_chunk_includes_pos (f->start_chunk, end_pos));
+  ASSERT (!f_chunk_includes_pos (f->shr->start_chunk, end_pos));
 
   if (maybe_ooo)
     rt = &f->ooo_deq_lookup;
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
 
   do
     {
@@ -1082,8 +1087,8 @@ f_unlink_chunks (svm_fifo_t * f, u32 end_pos, u8 maybe_ooo)
     return 0;
 
   prev->next = 0;
-  start = f->start_chunk;
-  f->start_chunk = c;
+  start = f->shr->start_chunk;
+  f->shr->start_chunk = c;
 
   return start;
 }
@@ -1103,22 +1108,23 @@ svm_fifo_dequeue (svm_fifo_t * f, u32 len, u8 * dst)
 
   len = clib_min (cursize, len);
 
-  if (!f->head_chunk)
-    f->head_chunk = svm_fifo_find_chunk (f, head);
+  if (!f->shr->head_chunk)
+    f->shr->head_chunk = svm_fifo_find_chunk (f, head);
 
-  svm_fifo_copy_from_chunk (f, f->head_chunk, head, dst, len, &f->head_chunk);
+  svm_fifo_copy_from_chunk (f, f->shr->head_chunk, head, dst, len,
+			    &f->shr->head_chunk);
   head = head + len;
 
   /* In order dequeues are not supported in combination with ooo peeking.
    * Use svm_fifo_dequeue_drop instead. */
   ASSERT (rb_tree_n_nodes (&f->ooo_deq_lookup) <= 1);
 
-  if (f_pos_geq (head, f_chunk_end (f->start_chunk)))
-    fsh_collect_chunks (f->fs_hdr, f->slice_index,
+  if (f_pos_geq (head, f_chunk_end (f->shr->start_chunk)))
+    fsh_collect_chunks (f->fs_hdr, f->shr->slice_index,
 			f_unlink_chunks (f, head, 0));
 
   /* store-rel: consumer owned index (paired with load-acq in producer) */
-  clib_atomic_store_rel_n (&f->head, head);
+  clib_atomic_store_rel_n (&f->shr->head, head);
 
   return len;
 }
@@ -1167,16 +1173,17 @@ svm_fifo_dequeue_drop (svm_fifo_t * f, u32 len)
   /* move head */
   head = head + total_drop_bytes;
 
-  if (f_pos_geq (head, f_chunk_end (f->start_chunk)))
+  if (f_pos_geq (head, f_chunk_end (f->shr->start_chunk)))
     {
-      fsh_collect_chunks (f->fs_hdr, f->slice_index,
+      fsh_collect_chunks (f->fs_hdr, f->shr->slice_index,
 			  f_unlink_chunks (f, head, 1));
-      f->head_chunk =
-	f_chunk_includes_pos (f->start_chunk, head) ? f->start_chunk : 0;
+      f->shr->head_chunk = f_chunk_includes_pos (f->shr->start_chunk, head) ?
+			     f->shr->start_chunk :
+			     0;
     }
 
   /* store-rel: consumer owned index (paired with load-acq in producer) */
-  clib_atomic_store_rel_n (&f->head, head);
+  clib_atomic_store_rel_n (&f->shr->head, head);
 
   return total_drop_bytes;
 }
@@ -1192,17 +1199,17 @@ svm_fifo_dequeue_drop_all (svm_fifo_t * f)
 
   f_load_head_tail_all_acq (f, &head, &tail);
 
-  if (!f->head_chunk || !f_chunk_includes_pos (f->head_chunk, head))
-    f->head_chunk = svm_fifo_find_chunk (f, head);
+  if (!f->shr->head_chunk || !f_chunk_includes_pos (f->shr->head_chunk, head))
+    f->shr->head_chunk = svm_fifo_find_chunk (f, head);
 
-  f->head_chunk = f_lookup_clear_deq_chunks (f, f->head_chunk, tail);
+  f->shr->head_chunk = f_lookup_clear_deq_chunks (f, f->shr->head_chunk, tail);
 
-  if (f_pos_geq (tail, f_chunk_end (f->start_chunk)))
-    fsh_collect_chunks (f->fs_hdr, f->slice_index,
+  if (f_pos_geq (tail, f_chunk_end (f->shr->start_chunk)))
+    fsh_collect_chunks (f->fs_hdr, f->shr->slice_index,
 			f_unlink_chunks (f, tail, 0));
 
   /* store-rel: consumer owned index (paired with load-acq in producer) */
-  clib_atomic_store_rel_n (&f->head, tail);
+  clib_atomic_store_rel_n (&f->shr->head, tail);
 }
 
 int
@@ -1212,10 +1219,10 @@ svm_fifo_fill_chunk_list (svm_fifo_t * f)
 
   f_load_head_tail_prod (f, &head, &tail);
 
-  if (f_chunk_end (f->end_chunk) - head >= f->size)
+  if (f_chunk_end (f->shr->end_chunk) - head >= f->shr->size)
     return 0;
 
-  if (f_try_chunk_alloc (f, head, tail, f->size - (tail - head)))
+  if (f_try_chunk_alloc (f, head, tail, f->shr->size - (tail - head)))
     return SVM_FIFO_EGROW;
 
   return 0;
@@ -1233,12 +1240,12 @@ svm_fifo_provision_chunks (svm_fifo_t *f, svm_fifo_seg_t *fs, u32 n_segs,
   if (f_free_count (f, head, tail) < len)
     return SVM_FIFO_EFULL;
 
-  n_avail = f_chunk_end (f->end_chunk) - tail;
+  n_avail = f_chunk_end (f->shr->end_chunk) - tail;
 
   if (n_avail < len && f_try_chunk_alloc (f, head, tail, len))
     return SVM_FIFO_EGROW;
 
-  c = f->tail_chunk;
+  c = f->shr->tail_chunk;
   head_pos = (tail - c->start_byte);
   fs[0].data = c->data + head_pos;
   fs[0].len = clib_min (c->length - head_pos, len);
@@ -1279,10 +1286,10 @@ svm_fifo_segments (svm_fifo_t * f, u32 offset, svm_fifo_seg_t * fs,
   to_read = clib_min (cursize - offset, max_bytes);
   start = head + offset;
 
-  if (!f->head_chunk)
-    f->head_chunk = svm_fifo_find_chunk (f, head);
+  if (!f->shr->head_chunk)
+    f->shr->head_chunk = svm_fifo_find_chunk (f, head);
 
-  c = f->head_chunk;
+  c = f->shr->head_chunk;
 
   while (!f_chunk_includes_pos (c, start))
     c = c->next;
@@ -1320,11 +1327,12 @@ svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf)
   /* Support only single chunk clones for now */
   ASSERT (svm_fifo_n_chunks (sf) == 1);
 
-  clib_memcpy_fast (df->head_chunk->data, sf->head_chunk->data, sf->size);
+  clib_memcpy_fast (df->shr->head_chunk->data, sf->shr->head_chunk->data,
+		    sf->shr->size);
 
   f_load_head_tail_all_acq (sf, &head, &tail);
-  clib_atomic_store_rel_n (&df->head, head);
-  clib_atomic_store_rel_n (&df->tail, tail);
+  clib_atomic_store_rel_n (&df->shr->head, head);
+  clib_atomic_store_rel_n (&df->shr->tail, tail);
 }
 
 u32
@@ -1347,23 +1355,23 @@ svm_fifo_init_pointers (svm_fifo_t * f, u32 head, u32 tail)
 {
   svm_fifo_chunk_t *c;
 
-  clib_atomic_store_rel_n (&f->head, head);
-  clib_atomic_store_rel_n (&f->tail, tail);
+  clib_atomic_store_rel_n (&f->shr->head, head);
+  clib_atomic_store_rel_n (&f->shr->tail, tail);
 
   c = svm_fifo_find_chunk (f, head);
   ASSERT (c != 0);
-  f->head_chunk = f->ooo_deq = c;
+  f->shr->head_chunk = f->ooo_deq = c;
   c = svm_fifo_find_chunk (f, tail);
   ASSERT (c != 0);
-  f->tail_chunk = f->ooo_enq = c;
+  f->shr->tail_chunk = f->ooo_enq = c;
 }
 
 void
 svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber)
 {
-  if (f->n_subscribers >= SVM_FIFO_MAX_EVT_SUBSCRIBERS)
+  if (f->shr->n_subscribers >= SVM_FIFO_MAX_EVT_SUBSCRIBERS)
     return;
-  f->subscribers[f->n_subscribers++] = subscriber;
+  f->shr->subscribers[f->shr->n_subscribers++] = subscriber;
 }
 
 void
@@ -1371,12 +1379,12 @@ svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
 {
   int i;
 
-  for (i = 0; i < f->n_subscribers; i++)
+  for (i = 0; i < f->shr->n_subscribers; i++)
     {
-      if (f->subscribers[i] != subscriber)
+      if (f->shr->subscribers[i] != subscriber)
 	continue;
-      f->subscribers[i] = f->subscribers[f->n_subscribers - 1];
-      f->n_subscribers--;
+      f->shr->subscribers[i] = f->shr->subscribers[f->shr->n_subscribers - 1];
+      f->shr->n_subscribers--;
       break;
     }
 }
@@ -1386,17 +1394,20 @@ svm_fifo_is_sane (svm_fifo_t * f)
 {
   svm_fifo_chunk_t *tmp;
 
-  if (f->head_chunk && !f_chunk_includes_pos (f->head_chunk, f->head))
+  if (f->shr->head_chunk &&
+      !f_chunk_includes_pos (f->shr->head_chunk, f->shr->head))
     return 0;
-  if (f->tail_chunk && !f_chunk_includes_pos (f->tail_chunk, f->tail))
+  if (f->shr->tail_chunk &&
+      !f_chunk_includes_pos (f->shr->tail_chunk, f->shr->tail))
     return 0;
   if (f->ooo_deq)
     {
       if (rb_tree_is_init (&f->ooo_deq_lookup))
 	{
-	  if (f_pos_lt (f->ooo_deq->start_byte, f->start_chunk->start_byte)
-	      || f_pos_gt (f->ooo_deq->start_byte,
-			   f_chunk_end (f->end_chunk)))
+	  if (f_pos_lt (f->ooo_deq->start_byte,
+			f->shr->start_chunk->start_byte) ||
+	      f_pos_gt (f->ooo_deq->start_byte,
+			f_chunk_end (f->shr->end_chunk)))
 	    return 0;
 
 	  tmp = f_find_chunk_rbtree (&f->ooo_deq_lookup,
@@ -1411,9 +1422,10 @@ svm_fifo_is_sane (svm_fifo_t * f)
     {
       if (rb_tree_is_init (&f->ooo_enq_lookup))
 	{
-	  if (f_pos_lt (f->ooo_enq->start_byte, f->start_chunk->start_byte)
-	      || f_pos_gt (f->ooo_enq->start_byte,
-			   f_chunk_end (f->end_chunk)))
+	  if (f_pos_lt (f->ooo_enq->start_byte,
+			f->shr->start_chunk->start_byte) ||
+	      f_pos_gt (f->ooo_enq->start_byte,
+			f_chunk_end (f->shr->end_chunk)))
 	    return 0;
 
 	  tmp = f_find_chunk_rbtree (&f->ooo_enq_lookup,
@@ -1421,19 +1433,19 @@ svm_fifo_is_sane (svm_fifo_t * f)
 	}
       else
 	{
-	  tmp = svm_fifo_find_next_chunk (f, f->tail_chunk,
+	  tmp = svm_fifo_find_next_chunk (f, f->shr->tail_chunk,
 					  f->ooo_enq->start_byte);
 	}
       if (tmp != f->ooo_enq)
 	return 0;
     }
 
-  if (f->start_chunk->next)
+  if (f->shr->start_chunk->next)
     {
       svm_fifo_chunk_t *c, *prev = 0, *tmp;
       u32 chunks_bytes = 0;
 
-      c = f->start_chunk;
+      c = f->shr->start_chunk;
       do
 	{
 	  tmp = svm_fifo_find_chunk (f, c->start_byte);
@@ -1467,7 +1479,7 @@ svm_fifo_is_sane (svm_fifo_t * f)
 	}
       while (c);
 
-      if (chunks_bytes < f->tail - f->head)
+      if (chunks_bytes < f->shr->tail - f->shr->head)
 	return 0;
     }
 
@@ -1480,7 +1492,7 @@ svm_fifo_n_chunks (svm_fifo_t * f)
   svm_fifo_chunk_t *c;
   int n_chunks = 0;
 
-  c = f->start_chunk;
+  c = f->shr->start_chunk;
   while (c)
     {
       n_chunks++;
@@ -1544,10 +1556,10 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
   trace_len = 0;
 #endif
 
-  placeholder_fifo = svm_fifo_alloc (f->size);
-  svm_fifo_init (f, f->size);
-  clib_memset (f->head_chunk->data, 0xFF, f->size);
-  vec_validate (data, f->size);
+  placeholder_fifo = svm_fifo_alloc (f->shr->size);
+  svm_fifo_init (f, f->shr->size);
+  clib_memset (f->shr->head_chunk->data, 0xFF, f->shr->size);
+  vec_validate (data, f->shr->size);
   for (i = 0; i < vec_len (data); i++)
     data[i] = i;
 
@@ -1614,14 +1626,15 @@ format_svm_fifo (u8 * s, va_list * args)
 
   indent = format_get_indent (s);
   s = format (s, "cursize %u nitems %u has_event %d min_alloc %u\n",
-	      svm_fifo_max_dequeue (f), f->size, f->has_event, f->min_alloc);
+	      svm_fifo_max_dequeue (f), f->shr->size, f->shr->has_event,
+	      f->shr->min_alloc);
   s = format (s, "%Uhead %u tail %u segment manager %u\n", format_white_space,
-	      indent, f->head, f->tail, f->segment_manager);
+	      indent, f->shr->head, f->shr->tail, f->segment_manager);
 
   if (verbose > 1)
     s = format (s, "%Uvpp session %d thread %d app session %d thread %d\n",
-		format_white_space, indent, f->master_session_index,
-		f->master_thread_index, f->client_session_index,
+		format_white_space, indent, f->shr->master_session_index,
+		f->master_thread_index, f->shr->client_session_index,
 		f->client_thread_index);
 
   if (verbose)
diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index 5656e63d998..5845d7042af 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -80,9 +80,9 @@ static inline void
 f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
 {
   /* load-relaxed: consumer owned index */
-  *head = f->head;
+  *head = f->shr->head;
   /* load-acq: consumer foreign index (paired with store-rel in producer) */
-  *tail = clib_atomic_load_acq_n (&f->tail);
+  *tail = clib_atomic_load_acq_n (&f->shr->tail);
 }
 
 /** Load head and tail optimized for producer
@@ -93,9 +93,9 @@ static inline void
 f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
 {
   /* load relaxed: producer owned index */
-  *tail = f->tail;
+  *tail = f->shr->tail;
   /* load-acq: producer foreign index (paired with store-rel in consumer) */
-  *head = clib_atomic_load_acq_n (&f->head);
+  *head = clib_atomic_load_acq_n (&f->shr->head);
 }
 
 /**
@@ -107,9 +107,9 @@ static inline void
 f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
 {
   /* load-acq : consumer foreign index (paired with store-rel) */
-  *tail = clib_atomic_load_acq_n (&f->tail);
+  *tail = clib_atomic_load_acq_n (&f->shr->tail);
   /* load-acq : producer foriegn index (paired with store-rel) */
-  *head = clib_atomic_load_acq_n (&f->head);
+  *head = clib_atomic_load_acq_n (&f->shr->head);
 }
 
 /**
@@ -131,7 +131,7 @@ f_cursize (svm_fifo_t * f, u32 head, u32 tail)
 static inline u32
 f_free_count (svm_fifo_t * f, u32 head, u32 tail)
 {
-  return (f->size - f_cursize (f, head, tail));
+  return (f->shr->size - f_cursize (f, head, tail));
 }
 
 always_inline u32
@@ -487,7 +487,7 @@ svm_fifo_max_dequeue (svm_fifo_t * f)
 static inline int
 svm_fifo_is_full_prod (svm_fifo_t * f)
 {
-  return (svm_fifo_max_dequeue_prod (f) == f->size);
+  return (svm_fifo_max_dequeue_prod (f) == f->shr->size);
 }
 
 /* Check if fifo is full.
@@ -499,7 +499,7 @@ svm_fifo_is_full_prod (svm_fifo_t * f)
 static inline int
 svm_fifo_is_full (svm_fifo_t * f)
 {
-  return (svm_fifo_max_dequeue (f) == f->size);
+  return (svm_fifo_max_dequeue (f) == f->shr->size);
 }
 
 /**
@@ -606,7 +606,7 @@ u32 svm_fifo_max_write_chunk (svm_fifo_t * f);
 static inline svm_fifo_chunk_t *
 svm_fifo_head_chunk (svm_fifo_t * f)
 {
-  return f->head_chunk;
+  return f->shr->head_chunk;
 }
 
 /**
@@ -618,10 +618,11 @@ svm_fifo_head_chunk (svm_fifo_t * f)
 static inline u8 *
 svm_fifo_head (svm_fifo_t * f)
 {
-  if (!f->head_chunk)
+  if (!f->shr->head_chunk)
     return 0;
   /* load-relaxed: consumer owned index */
-  return (f->head_chunk->data + (f->head - f->head_chunk->start_byte));
+  return (f->shr->head_chunk->data +
+	  (f->shr->head - f->shr->head_chunk->start_byte));
 }
 
 /**
@@ -633,7 +634,7 @@ svm_fifo_head (svm_fifo_t * f)
 static inline svm_fifo_chunk_t *
 svm_fifo_tail_chunk (svm_fifo_t * f)
 {
-  return f->tail_chunk;
+  return f->shr->tail_chunk;
 }
 
 /**
@@ -646,7 +647,8 @@ static inline u8 *
 svm_fifo_tail (svm_fifo_t * f)
 {
   /* load-relaxed: producer owned index */
-  return (f->tail_chunk->data + (f->tail - f->tail_chunk->start_byte));
+  return (f->shr->tail_chunk->data +
+	  (f->shr->tail - f->shr->tail_chunk->start_byte));
 }
 
 /**
@@ -658,7 +660,7 @@ svm_fifo_tail (svm_fifo_t * f)
 static inline u8
 svm_fifo_n_subscribers (svm_fifo_t * f)
 {
-  return f->n_subscribers;
+  return f->shr->n_subscribers;
 }
 
 /**
@@ -692,7 +694,7 @@ ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
 {
   u32 tail;
   /* load-relaxed: producer owned index */
-  tail = f->tail;
+  tail = f->shr->tail;
 
   return (s->start - tail);
 }
@@ -706,7 +708,7 @@ ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
 static inline u32
 svm_fifo_size (svm_fifo_t * f)
 {
-  return f->size;
+  return f->shr->size;
 }
 
 static inline void
@@ -714,8 +716,9 @@ svm_fifo_set_size (svm_fifo_t * f, u32 size)
 {
   if (size > (1 << f->fs_hdr->max_log2_fifo_size))
     return;
-  fsh_virtual_mem_update (f->fs_hdr, f->slice_index, (int) f->size - size);
-  f->size = size;
+  fsh_virtual_mem_update (f->fs_hdr, f->shr->slice_index,
+			  (int) f->shr->size - size);
+  f->shr->size = size;
 }
 
 /**
@@ -727,7 +730,7 @@ svm_fifo_set_size (svm_fifo_t * f, u32 size)
 static inline int
 svm_fifo_has_event (svm_fifo_t * f)
 {
-  return f->has_event;
+  return f->shr->has_event;
 }
 
 /**
@@ -741,7 +744,7 @@ svm_fifo_has_event (svm_fifo_t * f)
 always_inline u8
 svm_fifo_set_event (svm_fifo_t * f)
 {
-  return !clib_atomic_swap_rel_n (&f->has_event, 1);
+  return !clib_atomic_swap_rel_n (&f->shr->has_event, 1);
 }
 
 /**
@@ -754,7 +757,7 @@ svm_fifo_set_event (svm_fifo_t * f)
 always_inline void
 svm_fifo_unset_event (svm_fifo_t * f)
 {
-  clib_atomic_swap_acq_n (&f->has_event, 0);
+  clib_atomic_swap_acq_n (&f->shr->has_event, 0);
 }
 
 /**
@@ -768,7 +771,7 @@ svm_fifo_unset_event (svm_fifo_t * f)
 static inline void
 svm_fifo_add_want_deq_ntf (svm_fifo_t * f, u8 ntf_type)
 {
-  f->want_deq_ntf |= ntf_type;
+  f->shr->want_deq_ntf |= ntf_type;
 }
 
 /**
@@ -782,7 +785,7 @@ svm_fifo_add_want_deq_ntf (svm_fifo_t * f, u8 ntf_type)
 static inline void
 svm_fifo_del_want_deq_ntf (svm_fifo_t * f, u8 ntf_type)
 {
-  f->want_deq_ntf &= ~ntf_type;
+  f->shr->want_deq_ntf &= ~ntf_type;
 }
 
 /**
@@ -800,7 +803,8 @@ static inline void
 svm_fifo_clear_deq_ntf (svm_fifo_t * f)
 {
   /* Set the flag if want_notif_if_full was the only ntf requested */
-  f->has_deq_ntf = f->want_deq_ntf == SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL;
+  f->shr->has_deq_ntf =
+    f->shr->want_deq_ntf == SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL;
   svm_fifo_del_want_deq_ntf (f, SVM_FIFO_WANT_DEQ_NOTIF);
 }
 
@@ -816,7 +820,7 @@ svm_fifo_clear_deq_ntf (svm_fifo_t * f)
 static inline void
 svm_fifo_reset_has_deq_ntf (svm_fifo_t * f)
 {
-  f->has_deq_ntf = 0;
+  f->shr->has_deq_ntf = 0;
 }
 
 /**
@@ -832,7 +836,7 @@ svm_fifo_reset_has_deq_ntf (svm_fifo_t * f)
 static inline u8
 svm_fifo_needs_deq_ntf (svm_fifo_t * f, u32 n_last_deq)
 {
-  u8 want_ntf = f->want_deq_ntf;
+  u8 want_ntf = f->shr->want_deq_ntf;
 
   if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_DEQ_NOTIF))
     return 0;
@@ -841,13 +845,14 @@ svm_fifo_needs_deq_ntf (svm_fifo_t * f, u32 n_last_deq)
   if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL)
     {
       u32 max_deq = svm_fifo_max_dequeue_cons (f);
-      u32 size = f->size;
-      if (!f->has_deq_ntf && max_deq < size && max_deq + n_last_deq >= size)
+      u32 size = f->shr->size;
+      if (!f->shr->has_deq_ntf && max_deq < size &&
+	  max_deq + n_last_deq >= size)
 	return 1;
     }
   if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY)
     {
-      if (!f->has_deq_ntf && svm_fifo_is_empty (f))
+      if (!f->shr->has_deq_ntf && svm_fifo_is_empty (f))
 	return 1;
     }
   return 0;
diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c
index c5dcd39038e..ea938113615 100644
--- a/src/vcl/vcl_private.c
+++ b/src/vcl/vcl_private.c
@@ -374,6 +374,51 @@ vcl_segment_detach (u64 segment_handle)
   VDBG (0, "detached segment %u handle %u", segment_index, segment_handle);
 }
 
+int
+vcl_segment_attach_session (uword segment_handle, uword rxf_offset,
+			    uword txf_offset, u8 is_ct, vcl_session_t *s)
+{
+  svm_fifo_shared_t *rxsf, *txsf;
+  svm_fifo_t *rxf, *txf;
+  fifo_segment_t *fs;
+  u32 fs_index;
+
+  fs_index = vcl_segment_table_lookup (segment_handle);
+  if (fs_index == VCL_INVALID_SEGMENT_INDEX)
+    {
+      VDBG (0, "ERROR: segment for session %u is not mounted!",
+	    s->session_index);
+      return -1;
+    }
+
+  rxsf = uword_to_pointer (rxf_offset, svm_fifo_shared_t *);
+  txsf = uword_to_pointer (txf_offset, svm_fifo_shared_t *);
+
+  clib_rwlock_reader_lock (&vcm->segment_table_lock);
+
+  fs = fifo_segment_get_segment (&vcm->segment_main, fs_index);
+  rxf = fifo_segment_alloc_fifo_w_shared (fs, rxsf);
+  txf = fifo_segment_alloc_fifo_w_shared (fs, txsf);
+
+  clib_rwlock_reader_unlock (&vcm->segment_table_lock);
+
+  if (!is_ct)
+    {
+      rxsf->client_session_index = s->session_index;
+      txsf->client_session_index = s->session_index;
+      rxf->client_thread_index = vcl_get_worker_index ();
+      txf->client_thread_index = vcl_get_worker_index ();
+      s->rx_fifo = rxf;
+      s->tx_fifo = txf;
+    }
+  else
+    {
+      s->ct_rx_fifo = rxf;
+      s->ct_tx_fifo = txf;
+    }
+
+  return 0;
+}
 
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index 0d26e64917c..637581b1b4b 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -685,6 +685,9 @@ int vcl_segment_attach (u64 segment_handle, char *name,
 void vcl_segment_detach (u64 segment_handle);
 void vcl_send_session_unlisten (vcl_worker_t * wrk, vcl_session_t * s);
 
+int vcl_segment_attach_session (uword segment_handle, uword rxf_offset,
+				uword txf_offset, u8 is_ct, vcl_session_t *s);
+
 /*
  * VCL Binary API
  */
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 58c13c28763..734d062669e 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -22,21 +22,6 @@
 
 __thread uword __vcl_worker_index = ~0;
 
-static int
-vcl_segment_is_not_mounted (vcl_worker_t * wrk, u64 segment_handle)
-{
-  u32 segment_index;
-
-  if (segment_handle == VCL_INVALID_SEGMENT_HANDLE)
-    return 0;
-
-  segment_index = vcl_segment_table_lookup (segment_handle);
-  if (segment_index != VCL_INVALID_SEGMENT_INDEX)
-    return 0;
-
-  return 1;
-}
-
 static inline int
 vcl_mq_dequeue_batch (vcl_worker_t * wrk, svm_msg_q_t * mq, u32 n_max_msg)
 {
@@ -377,7 +362,6 @@ vcl_session_accepted_handler (vcl_worker_t * wrk, session_accepted_msg_t * mp,
 			      u32 ls_index)
 {
   vcl_session_t *session, *listen_session;
-  svm_fifo_t *rx_fifo, *tx_fifo;
   svm_msg_q_t *evt_q;
 
   session = vcl_session_alloc (wrk);
@@ -390,26 +374,17 @@ vcl_session_accepted_handler (vcl_worker_t * wrk, session_accepted_msg_t * mp,
       goto error;
     }
 
-  if (vcl_segment_is_not_mounted (wrk, mp->segment_handle))
+  session->vpp_evt_q =
+    uword_to_pointer (mp->vpp_event_queue_address, svm_msg_q_t *);
+
+  if (vcl_segment_attach_session (mp->segment_handle, mp->server_rx_fifo,
+				  mp->server_tx_fifo, 0, session))
     {
-      VDBG (0, "ERROR: segment for session %u is not mounted!",
-	    session->session_index);
+      VDBG (0, "failed to attach fifos for %u", session->session_index);
       goto error;
     }
 
-  rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
-  tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  session->vpp_evt_q = uword_to_pointer (mp->vpp_event_queue_address,
-					 svm_msg_q_t *);
-  rx_fifo->client_session_index = session->session_index;
-  tx_fifo->client_session_index = session->session_index;
-  rx_fifo->client_thread_index = vcl_get_worker_index ();
-  tx_fifo->client_thread_index = vcl_get_worker_index ();
-
   session->vpp_handle = mp->handle;
-  session->rx_fifo = rx_fifo;
-  session->tx_fifo = tx_fifo;
-
   session->session_state = VCL_STATE_READY;
   session->transport.rmt_port = mp->rmt.port;
   session->transport.is_ip4 = mp->rmt.is_ip4;
@@ -448,7 +423,6 @@ static u32
 vcl_session_connected_handler (vcl_worker_t * wrk,
 			       session_connected_msg_t * mp)
 {
-  svm_fifo_t *rx_fifo, *tx_fifo;
   vcl_session_t *session = 0;
   u32 session_index;
 
@@ -472,38 +446,28 @@ vcl_session_connected_handler (vcl_worker_t * wrk,
   session->vpp_handle = mp->handle;
   session->vpp_evt_q = uword_to_pointer (mp->vpp_event_queue_address,
 					 svm_msg_q_t *);
-  rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
-  tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  if (vcl_segment_is_not_mounted (wrk, mp->segment_handle))
+
+  if (vcl_segment_attach_session (mp->segment_handle, mp->server_rx_fifo,
+				  mp->server_tx_fifo, 0, session))
     {
-      VDBG (0, "segment for session %u is not mounted!",
-	    session->session_index);
+      VDBG (0, "failed to attach fifos for %u", session->session_index);
       session->session_state = VCL_STATE_DETACHED;
       vcl_send_session_disconnect (wrk, session);
       return session_index;
     }
 
-  rx_fifo->client_session_index = session_index;
-  tx_fifo->client_session_index = session_index;
-  rx_fifo->client_thread_index = vcl_get_worker_index ();
-  tx_fifo->client_thread_index = vcl_get_worker_index ();
-
   if (mp->ct_rx_fifo)
     {
-      session->ct_rx_fifo = uword_to_pointer (mp->ct_rx_fifo, svm_fifo_t *);
-      session->ct_tx_fifo = uword_to_pointer (mp->ct_tx_fifo, svm_fifo_t *);
-      if (vcl_segment_is_not_mounted (wrk, mp->ct_segment_handle))
+      if (vcl_segment_attach_session (mp->ct_segment_handle, mp->ct_rx_fifo,
+				      mp->ct_tx_fifo, 1, session))
 	{
-	  VDBG (0, "ct segment for session %u is not mounted!",
-		session->session_index);
+	  VDBG (0, "failed to attach ct fifos for %u", session->session_index);
 	  session->session_state = VCL_STATE_DETACHED;
 	  vcl_send_session_disconnect (wrk, session);
 	  return session_index;
 	}
     }
 
-  session->rx_fifo = rx_fifo;
-  session->tx_fifo = tx_fifo;
   session->transport.is_ip4 = mp->lcl.is_ip4;
   clib_memcpy_fast (&session->transport.lcl_ip, &mp->lcl.ip,
 		    sizeof (session->transport.lcl_ip));
@@ -611,14 +575,13 @@ vcl_session_bound_handler (vcl_worker_t * wrk, session_bound_msg_t * mp)
 
   if (vcl_session_is_cl (session))
     {
-      svm_fifo_t *rx_fifo, *tx_fifo;
-      session->vpp_evt_q = uword_to_pointer (mp->vpp_evt_q, svm_msg_q_t *);
-      rx_fifo = uword_to_pointer (mp->rx_fifo, svm_fifo_t *);
-      rx_fifo->client_session_index = sid;
-      tx_fifo = uword_to_pointer (mp->tx_fifo, svm_fifo_t *);
-      tx_fifo->client_session_index = sid;
-      session->rx_fifo = rx_fifo;
-      session->tx_fifo = tx_fifo;
+      if (vcl_segment_attach_session (mp->segment_handle, mp->rx_fifo,
+				      mp->tx_fifo, 0, session))
+	{
+	  VDBG (0, "failed to attach fifos for %u", session->session_index);
+	  session->session_state = VCL_STATE_DETACHED;
+	  return VCL_INVALID_SESSION_INDEX;
+	}
     }
 
   VDBG (0, "session %u [0x%llx]: listen succeeded!", sid, mp->handle);
@@ -664,6 +627,7 @@ vcl_session_migrated_handler (vcl_worker_t * wrk, void *data)
 {
   session_migrated_msg_t *mp = (session_migrated_msg_t *) data;
   vcl_session_t *s;
+  u32 fs_index;
 
   s = vcl_session_get_w_vpp_handle (wrk, mp->handle);
   if (!s)
@@ -672,6 +636,14 @@ vcl_session_migrated_handler (vcl_worker_t * wrk, void *data)
       return;
     }
 
+  fs_index = vcl_segment_table_lookup (mp->segment_handle);
+  if (fs_index == VCL_INVALID_SEGMENT_INDEX)
+    {
+      VDBG (0, "segment for session %u is not mounted!", s->session_index);
+      s->session_state = VCL_STATE_DETACHED;
+      return;
+    }
+
   s->vpp_handle = mp->new_handle;
   s->vpp_evt_q = uword_to_pointer (mp->vpp_evt_q, svm_msg_q_t *);
 
@@ -680,7 +652,8 @@ vcl_session_migrated_handler (vcl_worker_t * wrk, void *data)
 
   /* Generate new tx event if we have outstanding data */
   if (svm_fifo_has_event (s->tx_fifo))
-    app_send_io_evt_to_vpp (s->vpp_evt_q, s->tx_fifo->master_session_index,
+    app_send_io_evt_to_vpp (s->vpp_evt_q,
+			    s->tx_fifo->shr->master_session_index,
 			    SESSION_IO_EVT_TX, SVM_Q_WAIT);
 
   VDBG (0, "Migrated 0x%lx to thread %u 0x%lx", mp->handle,
@@ -879,21 +852,15 @@ vcl_session_worker_update_reply_handler (vcl_worker_t * wrk, void *data)
       VDBG (0, "unknown handle 0x%llx", msg->handle);
       return;
     }
-  if (vcl_segment_is_not_mounted (wrk, msg->segment_handle))
-    {
-      clib_warning ("segment for session %u is not mounted!",
-		    s->session_index);
-      return;
-    }
 
   if (s->rx_fifo)
     {
-      s->rx_fifo = uword_to_pointer (msg->rx_fifo, svm_fifo_t *);
-      s->tx_fifo = uword_to_pointer (msg->tx_fifo, svm_fifo_t *);
-      s->rx_fifo->client_session_index = s->session_index;
-      s->tx_fifo->client_session_index = s->session_index;
-      s->rx_fifo->client_thread_index = wrk->wrk_index;
-      s->tx_fifo->client_thread_index = wrk->wrk_index;
+      if (vcl_segment_attach_session (msg->segment_handle, msg->rx_fifo,
+				      msg->tx_fifo, 0, s))
+	{
+	  VDBG (0, "failed to attach fifos for %u", s->session_index);
+	  return;
+	}
     }
   s->session_state = VCL_STATE_UPDATED;
 
@@ -1921,7 +1888,8 @@ read_again:
   if (PREDICT_FALSE (svm_fifo_needs_deq_ntf (rx_fifo, n_read)))
     {
       svm_fifo_clear_deq_ntf (rx_fifo);
-      app_send_io_evt_to_vpp (s->vpp_evt_q, s->rx_fifo->master_session_index,
+      app_send_io_evt_to_vpp (s->vpp_evt_q,
+			      s->rx_fifo->shr->master_session_index,
 			      SESSION_IO_EVT_RX, SVM_Q_WAIT);
     }
 
@@ -2132,8 +2100,8 @@ vppcom_session_write_inline (vcl_worker_t * wrk, vcl_session_t * s, void *buf,
 				   0 /* do_evt */ , SVM_Q_WAIT);
 
   if (svm_fifo_set_event (s->tx_fifo))
-    app_send_io_evt_to_vpp (s->vpp_evt_q, s->tx_fifo->master_session_index,
-			    et, SVM_Q_WAIT);
+    app_send_io_evt_to_vpp (
+      s->vpp_evt_q, s->tx_fifo->shr->master_session_index, et, SVM_Q_WAIT);
 
   /* The underlying fifo segment can run out of memory */
   if (PREDICT_FALSE (n_write < 0))
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index 79c6f288e93..096af1efa15 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -343,9 +343,7 @@ typedef struct session_bound_msg_
   uword rx_fifo;
   uword tx_fifo;
   uword vpp_evt_q;
-  u32 segment_size;
-  u8 segment_name_length;
-  u8 segment_name[128];
+  u64 segment_handle;
 } __clib_packed session_bound_msg_t;
 
 typedef struct session_unlisten_msg_
@@ -519,6 +517,7 @@ typedef struct session_migrate_msg_
   uword vpp_evt_q;
   session_handle_t handle;
   session_handle_t new_handle;
+  u64 segment_handle;
   u32 vpp_thread_index;
 } __clib_packed session_migrated_msg_t;
 
@@ -640,8 +639,8 @@ app_send_dgram_raw (svm_fifo_t * f, app_session_transport_t * at,
   if (do_evt)
     {
       if (svm_fifo_set_event (f))
-	app_send_io_evt_to_vpp (vpp_evt_q, f->master_session_index, evt_type,
-				noblock);
+	app_send_io_evt_to_vpp (vpp_evt_q, f->shr->master_session_index,
+				evt_type, noblock);
     }
   return len;
 }
@@ -664,8 +663,8 @@ app_send_stream_raw (svm_fifo_t * f, svm_msg_q_t * vpp_evt_q, u8 * data,
   if (do_evt)
     {
       if (rv > 0 && svm_fifo_set_event (f))
-	app_send_io_evt_to_vpp (vpp_evt_q, f->master_session_index, evt_type,
-				noblock);
+	app_send_io_evt_to_vpp (vpp_evt_q, f->shr->master_session_index,
+				evt_type, noblock);
     }
   return rv;
 }
diff --git a/src/vnet/session/application_local.c b/src/vnet/session/application_local.c
index 6e0aee2aae3..18e26f2c1cc 100644
--- a/src/vnet/session/application_local.c
+++ b/src/vnet/session/application_local.c
@@ -208,8 +208,8 @@ ct_init_accepted_session (app_worker_t * server_wrk,
     }
 
   sm_index = segment_manager_index (sm);
-  ls->rx_fifo->master_session_index = ls->session_index;
-  ls->tx_fifo->master_session_index = ls->session_index;
+  ls->rx_fifo->shr->master_session_index = ls->session_index;
+  ls->tx_fifo->shr->master_session_index = ls->session_index;
   ls->rx_fifo->master_thread_index = ls->thread_index;
   ls->tx_fifo->master_thread_index = ls->thread_index;
   ls->rx_fifo->segment_manager = sm_index;
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index dd159c6693c..d44f52c5340 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -200,10 +200,10 @@ app_worker_alloc_session_fifos (segment_manager_t * sm, session_t * s)
 						 &rx_fifo, &tx_fifo)))
     return rv;
 
-  rx_fifo->master_session_index = s->session_index;
+  rx_fifo->shr->master_session_index = s->session_index;
   rx_fifo->master_thread_index = s->thread_index;
 
-  tx_fifo->master_session_index = s->session_index;
+  tx_fifo->shr->master_session_index = s->session_index;
   tx_fifo->master_thread_index = s->thread_index;
 
   s->rx_fifo = rx_fifo;
@@ -711,7 +711,7 @@ app_send_io_evt_rx (app_worker_t * app_wrk, session_t * s)
 
   msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
   evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->session_index = s->rx_fifo->client_session_index;
+  evt->session_index = s->rx_fifo->shr->client_session_index;
   evt->event_type = SESSION_IO_EVT_RX;
 
   (void) svm_fifo_set_event (s->rx_fifo);
@@ -750,7 +750,7 @@ app_send_io_evt_tx (app_worker_t * app_wrk, session_t * s)
   msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
   evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
   evt->event_type = SESSION_IO_EVT_TX;
-  evt->session_index = s->tx_fifo->client_session_index;
+  evt->session_index = s->tx_fifo->shr->client_session_index;
 
   svm_msg_q_add_and_unlock (mq, &msg);
   return 0;
diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index bb3d7adc379..7683760fde9 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -211,6 +211,7 @@ segment_manager_del_segment (segment_manager_t * sm, fifo_segment_t * fs)
 	}
     }
 
+  fifo_segment_cleanup (fs);
   ssvm_delete (&fs->ssvm);
 
   if (CLIB_DEBUG)
@@ -612,12 +613,12 @@ segment_manager_del_sessions (segment_manager_t * sm)
          */
         while (f)
           {
-            session = session_get_if_valid (f->master_session_index,
-                                            f->master_thread_index);
-            if (session)
-              vec_add1 (handles, session_handle (session));
-            f = f->next;
-          }
+	    session = session_get_if_valid (f->shr->master_session_index,
+					    f->master_thread_index);
+	    if (session)
+	      vec_add1 (handles, session_handle (session));
+	    f = f->next;
+	  }
       }
 
     /* Instead of removing the segment, test when cleaning up disconnected
@@ -841,7 +842,7 @@ segment_manager_attach_fifo (segment_manager_t * sm, svm_fifo_t * f,
   fifo_segment_attach_fifo (fs, f, s->thread_index);
   segment_manager_segment_reader_unlock (sm);
 
-  f->master_session_index = s->session_index;
+  f->shr->master_session_index = s->session_index;
   f->master_thread_index = s->thread_index;
 }
 
@@ -1059,25 +1060,26 @@ segment_manager_format_sessions (segment_manager_t * sm, int verbose)
             u32 session_index, thread_index;
             session_t *session;
 
-            session_index = f->master_session_index;
-            thread_index = f->master_thread_index;
+	    session_index = f->shr->master_session_index;
+	    thread_index = f->master_thread_index;
 
-            session = session_get (session_index, thread_index);
-            str = format (0, "%U", format_session, session, verbose);
+	    session = session_get (session_index, thread_index);
+	    str = format (0, "%U", format_session, session, verbose);
 
-            if (verbose)
-              s = format (s, "%-40v%-20v%-15u%-10u", str, app_name,
-                          app_wrk->api_client_index, app_wrk->connects_seg_manager);
-            else
-              s = format (s, "%-40v%-20v", str, app_name);
+	    if (verbose)
+	      s = format (s, "%-40v%-20v%-15u%-10u", str, app_name,
+			  app_wrk->api_client_index,
+			  app_wrk->connects_seg_manager);
+	    else
+	      s = format (s, "%-40v%-20v", str, app_name);
 
-            vlib_cli_output (vm, "%v", s);
-            vec_reset_length (s);
-            vec_free (str);
+	    vlib_cli_output (vm, "%v", s);
+	    vec_reset_length (s);
+	    vec_free (str);
 
-            f = f->next;
-          }
-        vec_free (s);
+	    f = f->next;
+	  }
+	vec_free (s);
       }
   }
   /* *INDENT-ON* */
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index b0a17bbb214..962df556de9 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -78,7 +78,7 @@ session_send_evt_to_thread (void *data, void *args, u32 thread_index,
 int
 session_send_io_evt_to_thread (svm_fifo_t * f, session_evt_type_t evt_type)
 {
-  return session_send_evt_to_thread (&f->master_session_index, 0,
+  return session_send_evt_to_thread (&f->shr->master_session_index, 0,
 				     f->master_thread_index, evt_type);
 }
 
@@ -436,8 +436,8 @@ session_fifo_tuning (session_t * s, svm_fifo_t * f,
 	{
 	  segment_manager_t *sm;
 	  sm = segment_manager_get (f->segment_manager);
-	  ASSERT (f->size >= 4096);
-	  ASSERT (f->size <= sm->max_fifo_size);
+	  ASSERT (f->shr->size >= 4096);
+	  ASSERT (f->shr->size <= sm->max_fifo_size);
 	}
     }
 }
@@ -611,9 +611,9 @@ session_notify_subscribers (u32 app_index, session_t * s,
   if (!app)
     return -1;
 
-  for (i = 0; i < f->n_subscribers; i++)
+  for (i = 0; i < f->shr->n_subscribers; i++)
     {
-      app_wrk = application_get_worker (app, f->subscribers[i]);
+      app_wrk = application_get_worker (app, f->shr->subscribers[i]);
       if (!app_wrk)
 	continue;
       if (app_worker_lock_and_send_event (app_wrk, s, evt_type))
@@ -723,7 +723,7 @@ session_dequeue_notify (session_t * s)
 						     SESSION_IO_EVT_TX)))
     return -1;
 
-  if (PREDICT_FALSE (s->tx_fifo->n_subscribers))
+  if (PREDICT_FALSE (s->tx_fifo->shr->n_subscribers))
     return session_notify_subscribers (app_wrk->app_index, s,
 				       s->tx_fifo, SESSION_IO_EVT_TX);
 
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index d080ae44925..a8f92c3cc00 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -147,8 +147,8 @@ mq_send_session_accepted_cb (session_t * s)
   mp = (session_accepted_msg_t *) evt->data;
   clib_memset (mp, 0, sizeof (*mp));
   mp->context = app->app_index;
-  mp->server_rx_fifo = pointer_to_uword (s->rx_fifo);
-  mp->server_tx_fifo = pointer_to_uword (s->tx_fifo);
+  mp->server_rx_fifo = pointer_to_uword (s->rx_fifo->shr);
+  mp->server_tx_fifo = pointer_to_uword (s->tx_fifo->shr);
   mp->segment_handle = session_segment_handle (s);
   mp->flags = s->flags;
 
@@ -221,9 +221,9 @@ mq_notify_close_subscribers (u32 app_index, session_handle_t sh,
   if (!app)
     return;
 
-  for (i = 0; i < f->n_subscribers; i++)
+  for (i = 0; i < f->shr->n_subscribers; i++)
     {
-      if (!(app_wrk = application_get_worker (app, f->subscribers[i])))
+      if (!(app_wrk = application_get_worker (app, f->shr->subscribers[i])))
 	continue;
       mq_send_session_close_evt (app_wrk, sh, SESSION_CTRL_EVT_DISCONNECTED);
     }
@@ -305,8 +305,8 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
 
       session_get_endpoint (s, &mp->lcl, 1 /* is_lcl */ );
 
-      mp->server_rx_fifo = pointer_to_uword (s->rx_fifo);
-      mp->server_tx_fifo = pointer_to_uword (s->tx_fifo);
+      mp->server_rx_fifo = pointer_to_uword (s->rx_fifo->shr);
+      mp->server_tx_fifo = pointer_to_uword (s->tx_fifo->shr);
       mp->segment_handle = session_segment_handle (s);
     }
   else
@@ -320,12 +320,12 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
       mp->lcl.is_ip4 = cct->c_is_ip4;
       vpp_mq = session_main_get_vpp_event_queue (s->thread_index);
       mp->vpp_event_queue_address = pointer_to_uword (vpp_mq);
-      mp->server_rx_fifo = pointer_to_uword (s->rx_fifo);
-      mp->server_tx_fifo = pointer_to_uword (s->tx_fifo);
+      mp->server_rx_fifo = pointer_to_uword (s->rx_fifo->shr);
+      mp->server_tx_fifo = pointer_to_uword (s->tx_fifo->shr);
       mp->segment_handle = session_segment_handle (s);
       ss = ct_session_get_peer (s);
-      mp->ct_rx_fifo = pointer_to_uword (ss->tx_fifo);
-      mp->ct_tx_fifo = pointer_to_uword (ss->rx_fifo);
+      mp->ct_rx_fifo = pointer_to_uword (ss->tx_fifo->shr);
+      mp->ct_tx_fifo = pointer_to_uword (ss->rx_fifo->shr);
       mp->ct_segment_handle = session_segment_handle (ss);
     }
 
@@ -386,8 +386,9 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
 
   if (session_transport_service_type (ls) == TRANSPORT_SERVICE_CL)
     {
-      mp->rx_fifo = pointer_to_uword (ls->rx_fifo);
-      mp->tx_fifo = pointer_to_uword (ls->tx_fifo);
+      mp->rx_fifo = pointer_to_uword (ls->rx_fifo->shr);
+      mp->tx_fifo = pointer_to_uword (ls->tx_fifo->shr);
+      mp->segment_handle = session_segment_handle (ls);
     }
 
 done:
@@ -443,6 +444,7 @@ mq_send_session_migrate_cb (session_t * s, session_handle_t new_sh)
   mp->vpp_thread_index = session_thread_from_handle (new_sh);
   vpp_evt_q = session_main_get_vpp_event_queue (mp->vpp_thread_index);
   mp->vpp_evt_q = pointer_to_uword (vpp_evt_q);
+  mp->segment_handle = session_segment_handle (s);
   svm_msg_q_add_and_unlock (app_mq, msg);
 }
 
diff --git a/src/vnet/session/session_cli.c b/src/vnet/session/session_cli.c
index a9197547501..0d541748d9e 100644
--- a/src/vnet/session/session_cli.c
+++ b/src/vnet/session/session_cli.c
@@ -27,14 +27,14 @@ format_session_fifos (u8 * s, va_list * args)
     return s;
 
   s = format (s, " Rx fifo: %U", format_svm_fifo, ss->rx_fifo, verbose);
-  if (verbose > 2 && ss->rx_fifo->has_event)
+  if (verbose > 2 && ss->rx_fifo->shr->has_event)
     {
       found = session_node_lookup_fifo_event (ss->rx_fifo, e);
       s = format (s, " session node event: %s\n",
 		  found ? "found" : "not found");
     }
   s = format (s, " Tx fifo: %U", format_svm_fifo, ss->tx_fifo, verbose);
-  if (verbose > 2 && ss->tx_fifo->has_event)
+  if (verbose > 2 && ss->tx_fifo->shr->has_event)
     {
       found = session_node_lookup_fifo_event (ss->tx_fifo, e);
       s = format (s, " session node event: %s\n",
diff --git a/src/vnet/session/session_debug.c b/src/vnet/session/session_debug.c
index 33d1dc57196..c2718f3bfc2 100644
--- a/src/vnet/session/session_debug.c
+++ b/src/vnet/session/session_debug.c
@@ -187,7 +187,7 @@ session_node_cmp_event (session_event_t * e, svm_fifo_t * f)
     case SESSION_IO_EVT_BUILTIN_RX:
     case SESSION_IO_EVT_BUILTIN_TX:
     case SESSION_IO_EVT_TX_FLUSH:
-      if (e->session_index == f->master_session_index)
+      if (e->session_index == f->shr->master_session_index)
 	return 1;
       break;
     case SESSION_CTRL_EVT_CLOSE: