session: cleanup segment manager and fifo segment

Change-Id: I984f347fb465c0c405cef668d8690457e81788e2
Signed-off-by: Florin Coras <fcoras@cisco.com>

8 files changed, 402 insertions, 379 deletions

diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index 82b6dfef534..69cc87c9575 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -504,7 +504,7 @@ static int
 application_alloc_and_init (app_init_args_t * a)
 {
   ssvm_segment_type_t seg_type = SSVM_SEGMENT_MEMFD;
-  segment_manager_properties_t *props;
+  segment_manager_props_t *props;
   vl_api_registration_t *reg;
   application_t *app;
   u64 *options;
@@ -553,7 +553,7 @@ application_alloc_and_init (app_init_args_t * a)
     app->flags |= APP_OPTIONS_FLAGS_USE_GLOBAL_SCOPE;
 
   props = application_segment_manager_properties (app);
-  segment_manager_properties_init (props);
+  segment_manager_props_init (props);
   props->segment_size = options[APP_OPTIONS_ADD_SEGMENT_SIZE];
   props->prealloc_fifos = options[APP_OPTIONS_PREALLOC_FIFO_PAIRS];
   if (options[APP_OPTIONS_ADD_SEGMENT_SIZE])
@@ -719,7 +719,7 @@ application_alloc_worker_and_init (application_t * app, app_worker_t ** wrk)
   /*
    * Setup first segment manager
    */
-  sm = segment_manager_new ();
+  sm = segment_manager_alloc ();
   sm->app_wrk_index = app_wrk->wrk_index;
 
   if ((rv = segment_manager_init (sm, app->sm_properties.segment_size,
@@ -746,7 +746,7 @@ application_alloc_worker_and_init (application_t * app, app_worker_t ** wrk)
 int
 vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
 {
-  svm_fifo_segment_private_t *fs;
+  fifo_segment_t *fs;
   app_worker_map_t *wrk_map;
   app_worker_t *app_wrk;
   segment_manager_t *sm;
@@ -838,7 +838,7 @@ app_name_from_api_index (u32 api_client_index)
 int
 vnet_application_attach (vnet_app_attach_args_t * a)
 {
-  svm_fifo_segment_private_t *fs;
+  fifo_segment_t *fs;
   application_t *app = 0;
   app_worker_t *app_wrk;
   segment_manager_t *sm;
@@ -1313,13 +1313,13 @@ application_remove_proxy (application_t * app)
   /* *INDENT-ON* */
 }
 
-segment_manager_properties_t *
+segment_manager_props_t *
 application_segment_manager_properties (application_t * app)
 {
   return &app->sm_properties;
 }
 
-segment_manager_properties_t *
+segment_manager_props_t *
 application_get_segment_manager_properties (u32 app_index)
 {
   application_t *app = application_get (app_index);
@@ -1404,7 +1404,7 @@ format_application (u8 * s, va_list * args)
 {
   application_t *app = va_arg (*args, application_t *);
   CLIB_UNUSED (int verbose) = va_arg (*args, int);
-  segment_manager_properties_t *props;
+  segment_manager_props_t *props;
   const u8 *app_ns_name, *app_name;
   app_worker_map_t *wrk_map;
   app_worker_t *app_wrk;
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index 0cf97a75742..4485b743589 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -92,7 +92,7 @@ typedef struct application_
   session_cb_vft_t cb_fns;
 
   /** Segment manager properties. Shared by all segment managers */
-  segment_manager_properties_t sm_properties;
+  segment_manager_props_t sm_properties;
 
   /** Pool of mappings that keep track of workers associated to this app */
   app_worker_map_t *worker_maps;
@@ -197,10 +197,10 @@ u8 application_has_global_scope (application_t * app);
 void application_setup_proxy (application_t * app);
 void application_remove_proxy (application_t * app);
 
-segment_manager_properties_t *application_get_segment_manager_properties (u32
-									  app_index);
+segment_manager_props_t *application_get_segment_manager_properties (u32
+								     app_index);
 
-segment_manager_properties_t
+segment_manager_props_t
   * application_segment_manager_properties (application_t * app);
 
 /*
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index 3e6abdbec86..aa1a3f30877 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -17,9 +17,9 @@
 
 #include <vlibmemory/api.h>
 #include <svm/message_queue.h>
-#include <svm/svm_fifo_segment.h>
 #include <vnet/session/session_types.h>
 #include <vnet/tls/tls_test.h>
+#include <svm/fifo_segment.h>
 
 typedef struct _stream_session_cb_vft
 {
diff --git a/src/vnet/session/application_local.c b/src/vnet/session/application_local.c
index d2edd54512a..f868e1964cc 100644
--- a/src/vnet/session/application_local.c
+++ b/src/vnet/session/application_local.c
@@ -91,10 +91,10 @@ ct_session_endpoint (session_t * ll, session_endpoint_t * sep)
 int
 ct_session_connect_notify (session_t * ss)
 {
-  svm_fifo_segment_private_t *seg;
   ct_connection_t *sct, *cct;
   app_worker_t *client_wrk;
   segment_manager_t *sm;
+  fifo_segment_t *seg;
   u64 segment_handle;
   int is_fail = 0;
   session_t *cs;
@@ -167,11 +167,11 @@ ct_init_local_session (app_worker_t * client_wrk, app_worker_t * server_wrk,
 		       ct_connection_t * ct, session_t * ls, session_t * ll)
 {
   u32 round_rx_fifo_sz, round_tx_fifo_sz, sm_index, seg_size;
-  segment_manager_properties_t *props;
-  svm_fifo_segment_private_t *seg;
+  segment_manager_props_t *props;
   application_t *server;
   segment_manager_t *sm;
   u32 margin = 16 << 10;
+  fifo_segment_t *seg;
   u64 segment_handle;
   int seg_index, rv;
 
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 3cc84e84f1a..d98c437ec84 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -95,7 +95,7 @@ app_worker_free (app_worker_t * app_wrk)
       sm = segment_manager_get (app_wrk->connects_seg_manager);
       sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
       sm->first_is_protected = 0;
-      segment_manager_init_del (sm);
+      segment_manager_init_free (sm);
     }
 
   /* If first segment manager is used by a listener */
@@ -108,7 +108,7 @@ app_worker_free (app_worker_t * app_wrk)
       /* .. and has no fifos, e.g. it might be used for redirected sessions,
        * remove it */
       if (!segment_manager_has_fifos (sm))
-	segment_manager_del (sm);
+	segment_manager_free (sm);
     }
 
   pool_put (app_workers, app_wrk);
@@ -140,7 +140,7 @@ app_worker_alloc_segment_manager (app_worker_t * app_wrk)
       return sm;
     }
 
-  sm = segment_manager_new ();
+  sm = segment_manager_alloc ();
   sm->app_wrk_index = app_wrk->wrk_index;
 
   return sm;
@@ -238,7 +238,7 @@ app_worker_stop_listen_session (app_worker_t * app_wrk, session_t * ls)
     }
   else
     {
-      segment_manager_init_del (sm);
+      segment_manager_init_free (sm);
     }
   hash_unset (app_wrk->listeners_table, handle);
 }
@@ -698,63 +698,20 @@ format_app_worker (u8 * s, va_list * args)
 void
 app_worker_format_connects (app_worker_t * app_wrk, int verbose)
 {
-  svm_fifo_segment_private_t *fifo_segment;
-  vlib_main_t *vm = vlib_get_main ();
   segment_manager_t *sm;
-  const u8 *app_name;
-  u8 *s = 0;
 
   /* Header */
   if (!app_wrk)
     {
-      if (verbose)
-	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
-			 "API Client", "SegManager");
-      else
-	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
+      segment_manager_format_sessions (0, verbose);
       return;
     }
 
   if (app_wrk->connects_seg_manager == (u32) ~ 0)
     return;
 
-  app_name = application_name_from_index (app_wrk->app_index);
-
-  /* Across all fifo segments */
   sm = segment_manager_get (app_wrk->connects_seg_manager);
-
-  /* *INDENT-OFF* */
-  segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
-    svm_fifo_t *fifo;
-    u8 *str;
-
-    fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
-    while (fifo)
-      {
-        u32 session_index, thread_index;
-        session_t *session;
-
-        session_index = fifo->master_session_index;
-        thread_index = fifo->master_thread_index;
-
-        session = session_get (session_index, thread_index);
-        str = format (0, "%U", format_session, session, verbose);
-
-        if (verbose)
-          s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
-                      app_wrk->api_client_index, app_wrk->connects_seg_manager);
-        else
-          s = format (s, "%-40s%-20s", str, app_name);
-
-        vlib_cli_output (vm, "%v", s);
-        vec_reset_length (s);
-        vec_free (str);
-
-        fifo = fifo->next;
-      }
-    vec_free (s);
-  }));
-  /* *INDENT-ON* */
+  segment_manager_format_sessions (sm, verbose);
 }
 
 /*
diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index 2437f99098b..47c7f563542 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -17,34 +17,43 @@
 #include <vnet/session/session.h>
 #include <vnet/session/application.h>
 
-segment_manager_main_t segment_manager_main;
+typedef struct segment_manager_main_
+{
+  segment_manager_t *segment_managers;	/**< Pool of segment managers */
+  clib_valloc_main_t va_allocator;	/**< Virtual address allocator */
+  u32 seg_name_counter;			/**< Counter for segment names */
 
-/**
- * Counter used to build segment names
- */
-static u32 segment_name_counter = 0;
+  /*
+   * Configuration
+   */
+  u32 default_fifo_size;		/**< default rx/tx fifo size */
+  u32 default_segment_size;		/**< default fifo segment size */
+  u32 default_app_mq_size;		/**< default app msg q size */
+} segment_manager_main_t;
 
-/**
- * Default fifo and segment size. TODO config.
- */
-static u32 default_fifo_size = 1 << 12;
-static u32 default_segment_size = 1 << 20;
-static u32 default_app_evt_queue_size = 128;
+static segment_manager_main_t sm_main;
 
-segment_manager_properties_t *
+#define segment_manager_foreach_segment_w_lock(VAR, SM, BODY)		\
+do {									\
+    clib_rwlock_reader_lock (&(SM)->segments_rwlock);			\
+    pool_foreach((VAR), ((SM)->segments), (BODY));			\
+    clib_rwlock_reader_unlock (&(SM)->segments_rwlock);			\
+} while (0)
+
+static segment_manager_props_t *
 segment_manager_properties_get (segment_manager_t * sm)
 {
   app_worker_t *app_wrk = app_worker_get (sm->app_wrk_index);
   return application_get_segment_manager_properties (app_wrk->app_index);
 }
 
-segment_manager_properties_t *
-segment_manager_properties_init (segment_manager_properties_t * props)
+segment_manager_props_t *
+segment_manager_props_init (segment_manager_props_t * props)
 {
-  props->add_segment_size = default_segment_size;
-  props->rx_fifo_size = default_fifo_size;
-  props->tx_fifo_size = default_fifo_size;
-  props->evt_q_size = default_app_evt_queue_size;
+  props->add_segment_size = sm_main.default_segment_size;
+  props->rx_fifo_size = sm_main.default_fifo_size;
+  props->tx_fifo_size = sm_main.default_fifo_size;
+  props->evt_q_size = sm_main.default_app_mq_size;
   return props;
 }
 
@@ -61,20 +70,103 @@ segment_manager_app_detach (segment_manager_t * sm)
 }
 
 always_inline u32
-segment_manager_segment_index (segment_manager_t * sm,
-			       svm_fifo_segment_private_t * seg)
+segment_manager_segment_index (segment_manager_t * sm, fifo_segment_t * seg)
 {
   return (seg - sm->segments);
 }
 
 /**
+ * Adds segment to segment manager's pool
+ *
+ * If needed a writer's lock is acquired before allocating a new segment
+ * to avoid affecting any of the segments pool readers.
+ */
+int
+segment_manager_add_segment (segment_manager_t * sm, u32 segment_size)
+{
+  segment_manager_main_t *smm = &sm_main;
+  u32 rnd_margin = 128 << 10, fs_index = ~0, page_size;
+  uword baseva = (uword) ~ 0ULL, alloc_size;
+  segment_manager_props_t *props;
+  fifo_segment_t *fs;
+  u8 *seg_name;
+  int rv;
+
+  props = segment_manager_properties_get (sm);
+
+  /* Not configured for addition of new segments and not first */
+  if (!props->add_segment && !segment_size)
+    {
+      clib_warning ("cannot allocate new segment");
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
+
+  /*
+   * Allocate fifo segment and lock if needed
+   */
+  if (vlib_num_workers ())
+    clib_rwlock_writer_lock (&sm->segments_rwlock);
+
+  pool_get_zero (sm->segments, fs);
+
+  /*
+   * Initialize ssvm segment and svm fifo private header
+   */
+  segment_size = segment_size ? segment_size : props->add_segment_size;
+  page_size = clib_mem_get_page_size ();
+  segment_size = (segment_size + page_size - 1) & ~(page_size - 1);
+  if (props->segment_type != SSVM_SEGMENT_PRIVATE)
+    {
+      seg_name = format (0, "%d-%d%c", getpid (), smm->seg_name_counter++, 0);
+      alloc_size = (uword) segment_size + rnd_margin;
+      baseva = clib_valloc_alloc (&smm->va_allocator, alloc_size, 0);
+      if (!baseva)
+	{
+	  clib_warning ("out of space for segments");
+	  pool_put (sm->segments, fs);
+	  goto done;
+	}
+    }
+  else
+    seg_name = format (0, "%s%c", "process-private-segment", 0);
+
+  fs->ssvm.ssvm_size = segment_size;
+  fs->ssvm.name = seg_name;
+  fs->ssvm.requested_va = baseva;
+
+  if ((rv = ssvm_master_init (&fs->ssvm, props->segment_type)))
+    {
+      clib_warning ("svm_master_init ('%v', %u) failed", seg_name,
+		    segment_size);
+
+      if (props->segment_type != SSVM_SEGMENT_PRIVATE)
+	clib_valloc_free (&smm->va_allocator, baseva);
+      pool_put (sm->segments, fs);
+      goto done;
+    }
+
+  fifo_segment_init (fs);
+
+  /*
+   * Save segment index before dropping lock, if any held
+   */
+  fs_index = fs - sm->segments;
+
+done:
+
+  if (vlib_num_workers ())
+    clib_rwlock_writer_unlock (&sm->segments_rwlock);
+
+  return fs_index;
+}
+
+/**
  * Remove segment without lock
  */
 void
-segment_manager_del_segment (segment_manager_t * sm,
-			     svm_fifo_segment_private_t * fs)
+segment_manager_del_segment (segment_manager_t * sm, fifo_segment_t * fs)
 {
-  segment_manager_main_t *smm = &segment_manager_main;
+  segment_manager_main_t *smm = &sm_main;
 
   if (ssvm_type (&fs->ssvm) != SSVM_SEGMENT_PRIVATE)
     {
@@ -103,12 +195,12 @@ segment_manager_del_segment (segment_manager_t * sm,
 static inline void
 segment_manager_lock_and_del_segment (segment_manager_t * sm, u32 fs_index)
 {
-  svm_fifo_segment_private_t *fs;
+  fifo_segment_t *fs;
   u8 is_prealloc;
 
   clib_rwlock_writer_lock (&sm->segments_rwlock);
   fs = segment_manager_get_segment (sm, fs_index);
-  is_prealloc = svm_fifo_segment_flags (fs) & FIFO_SEGMENT_F_IS_PREALLOCATED;
+  is_prealloc = fifo_segment_flags (fs) & FIFO_SEGMENT_F_IS_PREALLOCATED;
   if (is_prealloc && !segment_manager_app_detached (sm))
     {
       clib_rwlock_writer_unlock (&sm->segments_rwlock);
@@ -122,7 +214,7 @@ segment_manager_lock_and_del_segment (segment_manager_t * sm, u32 fs_index)
 /**
  * Reads a segment from the segment manager's pool without lock
  */
-svm_fifo_segment_private_t *
+fifo_segment_t *
 segment_manager_get_segment (segment_manager_t * sm, u32 segment_index)
 {
   return pool_elt_at_index (sm->segments, segment_index);
@@ -130,13 +222,13 @@ segment_manager_get_segment (segment_manager_t * sm, u32 segment_index)
 
 u64
 segment_manager_segment_handle (segment_manager_t * sm,
-				svm_fifo_segment_private_t * segment)
+				fifo_segment_t * segment)
 {
   u32 segment_index = segment_manager_segment_index (sm, segment);
   return (((u64) segment_manager_index (sm) << 32) | segment_index);
 }
 
-void
+static void
 segment_manager_parse_segment_handle (u64 segment_handle, u32 * sm_index,
 				      u32 * segment_index)
 {
@@ -144,7 +236,14 @@ segment_manager_parse_segment_handle (u64 segment_handle, u32 * sm_index,
   *segment_index = segment_handle & 0xFFFFFFFF;
 }
 
-svm_fifo_segment_private_t *
+u64
+segment_manager_make_segment_handle (u32 segment_manager_index,
+				     u32 segment_index)
+{
+  return (((u64) segment_manager_index << 32) | segment_index);
+}
+
+fifo_segment_t *
 segment_manager_get_segment_w_handle (u64 segment_handle)
 {
   u32 sm_index, segment_index;
@@ -165,7 +264,7 @@ segment_manager_get_segment_w_handle (u64 segment_handle)
  * @ref segment_manager_segment_reader_unlock once it finishes working with
  * the segment.
  */
-svm_fifo_segment_private_t *
+fifo_segment_t *
 segment_manager_get_segment_w_lock (segment_manager_t * sm, u32 segment_index)
 {
   clib_rwlock_reader_lock (&sm->segments_rwlock);
@@ -185,98 +284,13 @@ segment_manager_segment_writer_unlock (segment_manager_t * sm)
   clib_rwlock_writer_unlock (&sm->segments_rwlock);
 }
 
-/**
- * Adds segment to segment manager's pool
- *
- * If needed a writer's lock is acquired before allocating a new segment
- * to avoid affecting any of the segments pool readers.
- */
-int
-segment_manager_add_segment (segment_manager_t * sm, u32 segment_size)
-{
-  segment_manager_main_t *smm = &segment_manager_main;
-  u32 rnd_margin = 128 << 10, seg_index = ~0, page_size;
-  segment_manager_properties_t *props;
-  uword baseva = (uword) ~ 0ULL, alloc_size;
-  svm_fifo_segment_private_t *seg;
-  u8 *seg_name;
-  int rv;
-
-  props = segment_manager_properties_get (sm);
-
-  /* Not configured for addition of new segments and not first */
-  if (!props->add_segment && !segment_size)
-    {
-      clib_warning ("cannot allocate new segment");
-      return VNET_API_ERROR_INVALID_VALUE;
-    }
-
-  /*
-   * Allocate fifo segment and lock if needed
-   */
-  if (vlib_num_workers ())
-    clib_rwlock_writer_lock (&sm->segments_rwlock);
-
-  pool_get_zero (sm->segments, seg);
-
-  /*
-   * Initialize ssvm segment and svm fifo private header
-   */
-  segment_size = segment_size ? segment_size : props->add_segment_size;
-  page_size = clib_mem_get_page_size ();
-  segment_size = (segment_size + page_size - 1) & ~(page_size - 1);
-  if (props->segment_type != SSVM_SEGMENT_PRIVATE)
-    {
-      seg_name = format (0, "%d-%d%c", getpid (), segment_name_counter++, 0);
-      alloc_size = (uword) segment_size + rnd_margin;
-      baseva = clib_valloc_alloc (&smm->va_allocator, alloc_size, 0);
-      if (!baseva)
-	{
-	  clib_warning ("out of space for segments");
-	  pool_put (sm->segments, seg);
-	  goto done;
-	}
-    }
-  else
-    seg_name = format (0, "%s%c", "process-private-segment", 0);
-
-  seg->ssvm.ssvm_size = segment_size;
-  seg->ssvm.name = seg_name;
-  seg->ssvm.requested_va = baseva;
-
-  if ((rv = ssvm_master_init (&seg->ssvm, props->segment_type)))
-    {
-      clib_warning ("svm_master_init ('%v', %u) failed", seg_name,
-		    segment_size);
-
-      if (props->segment_type != SSVM_SEGMENT_PRIVATE)
-	clib_valloc_free (&smm->va_allocator, baseva);
-      pool_put (sm->segments, seg);
-      goto done;
-    }
-
-  svm_fifo_segment_init (seg);
-
-  /*
-   * Save segment index before dropping lock, if any held
-   */
-  seg_index = seg - sm->segments;
-
-done:
-
-  if (vlib_num_workers ())
-    clib_rwlock_writer_unlock (&sm->segments_rwlock);
-
-  return seg_index;
-}
-
 segment_manager_t *
-segment_manager_new ()
+segment_manager_alloc (void)
 {
-  segment_manager_main_t *smm = &segment_manager_main;
+  segment_manager_main_t *smm = &sm_main;
   segment_manager_t *sm;
-  pool_get (smm->segment_managers, sm);
-  clib_memset (sm, 0, sizeof (*sm));
+
+  pool_get_zero (smm->segment_managers, sm);
   clib_rwlock_init (&sm->segments_rwlock);
   return sm;
 }
@@ -292,13 +306,13 @@ segment_manager_init (segment_manager_t * sm, u32 first_seg_size,
   u32 rx_fifo_size, tx_fifo_size, pair_size;
   u32 rx_rounded_data_size, tx_rounded_data_size;
   u64 approx_total_size, max_seg_size = ((u64) 1 << 32) - (128 << 10);
-  segment_manager_properties_t *props;
-  svm_fifo_segment_private_t *segment;
+  segment_manager_props_t *props;
+  fifo_segment_t *segment;
   u32 approx_segment_count;
   int seg_index, i;
 
   props = segment_manager_properties_get (sm);
-  first_seg_size = clib_max (first_seg_size, default_segment_size);
+  first_seg_size = clib_max (first_seg_size, sm_main.default_segment_size);
 
   if (prealloc_fifo_pairs)
     {
@@ -330,11 +344,11 @@ segment_manager_init (segment_manager_t * sm, u32 first_seg_size,
 	  if (i == 0)
 	    sm->event_queue = segment_manager_alloc_queue (segment, props);
 
-	  svm_fifo_segment_preallocate_fifo_pairs (segment,
-						   props->rx_fifo_size,
-						   props->tx_fifo_size,
-						   &prealloc_fifo_pairs);
-	  svm_fifo_segment_flags (segment) = FIFO_SEGMENT_F_IS_PREALLOCATED;
+	  fifo_segment_preallocate_fifo_pairs (segment,
+					       props->rx_fifo_size,
+					       props->tx_fifo_size,
+					       &prealloc_fifo_pairs);
+	  fifo_segment_flags (segment) = FIFO_SEGMENT_F_IS_PREALLOCATED;
 	  if (prealloc_fifo_pairs == 0)
 	    break;
 	}
@@ -354,22 +368,87 @@ segment_manager_init (segment_manager_t * sm, u32 first_seg_size,
   return 0;
 }
 
+/**
+ * Cleanup segment manager.
+ */
+void
+segment_manager_free (segment_manager_t * sm)
+{
+  segment_manager_main_t *smm = &sm_main;
+  fifo_segment_t *fifo_segment;
+
+  ASSERT (!segment_manager_has_fifos (sm)
+	  && segment_manager_app_detached (sm));
+
+  /* If we have empty preallocated segments that haven't been removed, remove
+   * them now. Apart from that, the first segment in the first segment manager
+   * is not removed when all fifos are removed. It can only be removed when
+   * the manager is explicitly deleted/detached by the app. */
+  clib_rwlock_writer_lock (&sm->segments_rwlock);
+
+  /* *INDENT-OFF* */
+  pool_foreach (fifo_segment, sm->segments, ({
+    segment_manager_del_segment (sm, fifo_segment);
+  }));
+  /* *INDENT-ON* */
+
+  clib_rwlock_writer_unlock (&sm->segments_rwlock);
+
+  clib_rwlock_free (&sm->segments_rwlock);
+  if (CLIB_DEBUG)
+    clib_memset (sm, 0xfe, sizeof (*sm));
+  pool_put (smm->segment_managers, sm);
+}
+
+void
+segment_manager_init_free (segment_manager_t * sm)
+{
+  segment_manager_app_detach (sm);
+  if (segment_manager_has_fifos (sm))
+    segment_manager_del_sessions (sm);
+  else
+    {
+      ASSERT (!sm->first_is_protected || segment_manager_app_detached (sm));
+      segment_manager_free (sm);
+    }
+}
+
+segment_manager_t *
+segment_manager_get (u32 index)
+{
+  return pool_elt_at_index (sm_main.segment_managers, index);
+}
+
+segment_manager_t *
+segment_manager_get_if_valid (u32 index)
+{
+  if (pool_is_free_index (sm_main.segment_managers, index))
+    return 0;
+  return pool_elt_at_index (sm_main.segment_managers, index);
+}
+
+u32
+segment_manager_index (segment_manager_t * sm)
+{
+  return sm - sm_main.segment_managers;
+}
+
 u8
 segment_manager_has_fifos (segment_manager_t * sm)
 {
-  svm_fifo_segment_private_t *seg;
+  fifo_segment_t *seg;
   u8 first = 1;
 
   /* *INDENT-OFF* */
   segment_manager_foreach_segment_w_lock (seg, sm, ({
-    if (CLIB_DEBUG && !first && !svm_fifo_segment_has_fifos (seg)
-	&& !(svm_fifo_segment_flags (seg) & FIFO_SEGMENT_F_IS_PREALLOCATED))
+    if (CLIB_DEBUG && !first && !fifo_segment_has_fifos (seg)
+	&& !(fifo_segment_flags (seg) & FIFO_SEGMENT_F_IS_PREALLOCATED))
       {
 	clib_warning ("segment %d has no fifos!",
 	              segment_manager_segment_index (sm, seg));
 	first = 0;
       }
-    if (svm_fifo_segment_has_fifos (seg))
+    if (fifo_segment_has_fifos (seg))
       {
 	segment_manager_segment_reader_unlock (sm);
 	return 1;
@@ -386,7 +465,7 @@ segment_manager_has_fifos (segment_manager_t * sm)
 void
 segment_manager_del_sessions (segment_manager_t * sm)
 {
-  svm_fifo_segment_private_t *fifo_segment;
+  fifo_segment_t *fifo_segment;
   session_handle_t *handles = 0, *handle;
   session_t *session;
   svm_fifo_t *fifo;
@@ -396,7 +475,7 @@ segment_manager_del_sessions (segment_manager_t * sm)
   /* Across all fifo segments used by the server */
   /* *INDENT-OFF* */
   segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
-    fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
+    fifo = fifo_segment_get_fifo_list (fifo_segment);
 
     /*
      * Remove any residual sessions from the session lookup table
@@ -422,75 +501,25 @@ segment_manager_del_sessions (segment_manager_t * sm)
     session_close (session_get_from_handle (*handle));
 }
 
-/**
- * Removes segment manager.
- *
- * Since the fifos allocated in the segment keep backpointers to the sessions
- * prior to removing the segment, we call session disconnect. This
- * subsequently propagates into transport.
- */
-void
-segment_manager_del (segment_manager_t * sm)
-{
-  segment_manager_main_t *smm = &segment_manager_main;
-  svm_fifo_segment_private_t *fifo_segment;
-
-  ASSERT (!segment_manager_has_fifos (sm)
-	  && segment_manager_app_detached (sm));
-
-  /* If we have empty preallocated segments that haven't been removed, remove
-   * them now. Apart from that, the first segment in the first segment manager
-   * is not removed when all fifos are removed. It can only be removed when
-   * the manager is explicitly deleted/detached by the app. */
-  clib_rwlock_writer_lock (&sm->segments_rwlock);
-
-  /* *INDENT-OFF* */
-  pool_foreach (fifo_segment, sm->segments, ({
-    segment_manager_del_segment (sm, fifo_segment);
-  }));
-  /* *INDENT-ON* */
-
-  clib_rwlock_writer_unlock (&sm->segments_rwlock);
-
-  clib_rwlock_free (&sm->segments_rwlock);
-  if (CLIB_DEBUG)
-    clib_memset (sm, 0xfe, sizeof (*sm));
-  pool_put (smm->segment_managers, sm);
-}
-
-void
-segment_manager_init_del (segment_manager_t * sm)
-{
-  segment_manager_app_detach (sm);
-  if (segment_manager_has_fifos (sm))
-    segment_manager_del_sessions (sm);
-  else
-    {
-      ASSERT (!sm->first_is_protected || segment_manager_app_detached (sm));
-      segment_manager_del (sm);
-    }
-}
-
 int
-segment_manager_try_alloc_fifos (svm_fifo_segment_private_t * fifo_segment,
+segment_manager_try_alloc_fifos (fifo_segment_t * fifo_segment,
 				 u32 rx_fifo_size, u32 tx_fifo_size,
 				 svm_fifo_t ** rx_fifo, svm_fifo_t ** tx_fifo)
 {
-  rx_fifo_size = clib_max (rx_fifo_size, default_fifo_size);
-  *rx_fifo = svm_fifo_segment_alloc_fifo (fifo_segment, rx_fifo_size,
-					  FIFO_SEGMENT_RX_FREELIST);
+  rx_fifo_size = clib_max (rx_fifo_size, sm_main.default_fifo_size);
+  *rx_fifo = fifo_segment_alloc_fifo (fifo_segment, rx_fifo_size,
+				      FIFO_SEGMENT_RX_FIFO);
 
-  tx_fifo_size = clib_max (tx_fifo_size, default_fifo_size);
-  *tx_fifo = svm_fifo_segment_alloc_fifo (fifo_segment, tx_fifo_size,
-					  FIFO_SEGMENT_TX_FREELIST);
+  tx_fifo_size = clib_max (tx_fifo_size, sm_main.default_fifo_size);
+  *tx_fifo = fifo_segment_alloc_fifo (fifo_segment, tx_fifo_size,
+				      FIFO_SEGMENT_TX_FIFO);
 
   if (*rx_fifo == 0)
     {
       /* This would be very odd, but handle it... */
       if (*tx_fifo != 0)
 	{
-	  svm_fifo_segment_free_fifo (fifo_segment, *tx_fifo,
-				      FIFO_SEGMENT_TX_FREELIST);
+	  fifo_segment_free_fifo (fifo_segment, *tx_fifo);
 	  *tx_fifo = 0;
 	}
       return -1;
@@ -499,8 +528,7 @@ segment_manager_try_alloc_fifos (svm_fifo_segment_private_t * fifo_segment,
     {
       if (*rx_fifo != 0)
 	{
-	  svm_fifo_segment_free_fifo (fifo_segment, *rx_fifo,
-				      FIFO_SEGMENT_RX_FREELIST);
+	  fifo_segment_free_fifo (fifo_segment, *rx_fifo);
 	  *rx_fifo = 0;
 	}
       return -1;
@@ -514,12 +542,12 @@ segment_manager_alloc_session_fifos (segment_manager_t * sm,
 				     svm_fifo_t ** rx_fifo,
 				     svm_fifo_t ** tx_fifo)
 {
-  svm_fifo_segment_private_t *fifo_segment = 0;
   int alloc_fail = 1, rv = 0, new_fs_index;
-  segment_manager_properties_t *props;
-  u32 sm_index, fifo_segment_index;
+  segment_manager_props_t *props;
+  fifo_segment_t *fs = 0;
+  u32 sm_index, fs_index;
   u8 added_a_segment = 0;
-  u64 segment_handle;
+  u64 fs_handle;
 
   props = segment_manager_properties_get (sm);
 
@@ -528,8 +556,8 @@ segment_manager_alloc_session_fifos (segment_manager_t * sm,
    */
 
   /* *INDENT-OFF* */
-  segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
-    alloc_fail = segment_manager_try_alloc_fifos (fifo_segment,
+  segment_manager_foreach_segment_w_lock (fs, sm, ({
+    alloc_fail = segment_manager_try_alloc_fifos (fs,
                                                   props->rx_fifo_size,
                                                   props->tx_fifo_size,
                                                   rx_fifo, tx_fifo);
@@ -548,18 +576,18 @@ alloc_check:
 
       ASSERT (rx_fifo && tx_fifo);
       sm_index = segment_manager_index (sm);
-      fifo_segment_index = segment_manager_segment_index (sm, fifo_segment);
+      fs_index = segment_manager_segment_index (sm, fs);
       (*tx_fifo)->segment_manager = sm_index;
       (*rx_fifo)->segment_manager = sm_index;
-      (*tx_fifo)->segment_index = fifo_segment_index;
-      (*rx_fifo)->segment_index = fifo_segment_index;
+      (*tx_fifo)->segment_index = fs_index;
+      (*rx_fifo)->segment_index = fs_index;
 
       if (added_a_segment)
 	{
 	  app_worker_t *app_wrk;
-	  segment_handle = segment_manager_segment_handle (sm, fifo_segment);
+	  fs_handle = segment_manager_segment_handle (sm, fs);
 	  app_wrk = app_worker_get (sm->app_wrk_index);
-	  rv = app_worker_add_segment_notify (app_wrk, segment_handle);
+	  rv = app_worker_add_segment_notify (app_wrk, fs_handle);
 	}
       /* Drop the lock after app is notified */
       segment_manager_segment_reader_unlock (sm);
@@ -582,9 +610,8 @@ alloc_check:
 	  clib_warning ("Failed to add new segment");
 	  return SESSION_ERROR_SEG_CREATE;
 	}
-      fifo_segment = segment_manager_get_segment_w_lock (sm, new_fs_index);
-      alloc_fail = segment_manager_try_alloc_fifos (fifo_segment,
-						    props->rx_fifo_size,
+      fs = segment_manager_get_segment_w_lock (sm, new_fs_index);
+      alloc_fail = segment_manager_try_alloc_fifos (fs, props->rx_fifo_size,
 						    props->tx_fifo_size,
 						    rx_fifo, tx_fifo);
       added_a_segment = 1;
@@ -600,7 +627,7 @@ alloc_check:
 void
 segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo, svm_fifo_t * tx_fifo)
 {
-  svm_fifo_segment_private_t *fifo_segment;
+  fifo_segment_t *fs;
   segment_manager_t *sm;
   u32 segment_index;
 
@@ -613,11 +640,9 @@ segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo, svm_fifo_t * tx_fifo)
     return;
 
   segment_index = rx_fifo->segment_index;
-  fifo_segment = segment_manager_get_segment_w_lock (sm, segment_index);
-  svm_fifo_segment_free_fifo (fifo_segment, rx_fifo,
-			      FIFO_SEGMENT_RX_FREELIST);
-  svm_fifo_segment_free_fifo (fifo_segment, tx_fifo,
-			      FIFO_SEGMENT_TX_FREELIST);
+  fs = segment_manager_get_segment_w_lock (sm, segment_index);
+  fifo_segment_free_fifo (fs, rx_fifo);
+  fifo_segment_free_fifo (fs, tx_fifo);
 
   /*
    * Try to remove svm segment if it has no fifos. This can be done only if
@@ -625,7 +650,7 @@ segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo, svm_fifo_t * tx_fifo)
    * and it is not protected. Moreover, if the segment is first and the app
    * has detached from the segment manager, remove the segment manager.
    */
-  if (!svm_fifo_segment_has_fifos (fifo_segment))
+  if (!fifo_segment_has_fifos (fs))
     {
       segment_manager_segment_reader_unlock (sm);
 
@@ -637,7 +662,7 @@ segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo, svm_fifo_t * tx_fifo)
       if (segment_manager_app_detached (sm)
 	  && !segment_manager_has_fifos (sm))
 	{
-	  segment_manager_del (sm);
+	  segment_manager_free (sm);
 	}
     }
   else
@@ -667,8 +692,8 @@ segment_manager_evt_q_expected_size (u32 q_len)
  * Must be called with lock held
  */
 svm_msg_q_t *
-segment_manager_alloc_queue (svm_fifo_segment_private_t * segment,
-			     segment_manager_properties_t * props)
+segment_manager_alloc_queue (fifo_segment_t * segment,
+			     segment_manager_props_t * props)
 {
   u32 fifo_evt_size, session_evt_size = 256, notif_q_size;
   svm_msg_q_cfg_t _cfg, *cfg = &_cfg;
@@ -700,13 +725,19 @@ segment_manager_alloc_queue (svm_fifo_segment_private_t * segment,
   return q;
 }
 
+svm_msg_q_t *
+segment_manager_event_queue (segment_manager_t * sm)
+{
+  return sm->event_queue;
+}
+
 /**
  * Frees shm queue allocated in the first segment
  */
 void
 segment_manager_dealloc_queue (segment_manager_t * sm, svm_queue_t * q)
 {
-  svm_fifo_segment_private_t *segment;
+  fifo_segment_t *segment;
   ssvm_shared_header_t *sh;
   void *oldheap;
 
@@ -727,21 +758,25 @@ segment_manager_dealloc_queue (segment_manager_t * sm, svm_queue_t * q)
 void
 segment_manager_main_init (segment_manager_main_init_args_t * a)
 {
-  segment_manager_main_t *sm = &segment_manager_main;
+  segment_manager_main_t *sm = &sm_main;
   clib_valloc_chunk_t _ip, *ip = &_ip;
 
   ip->baseva = a->baseva;
   ip->size = a->size;
 
   clib_valloc_init (&sm->va_allocator, ip, 1 /* lock */ );
+
+  sm->default_fifo_size = 1 << 12;
+  sm->default_segment_size = 1 << 20;
+  sm->default_app_mq_size = 128;
 }
 
 static clib_error_t *
 segment_manager_show_fn (vlib_main_t * vm, unformat_input_t * input,
 			 vlib_cli_command_t * cmd)
 {
-  segment_manager_main_t *smm = &segment_manager_main;
-  svm_fifo_segment_private_t *seg;
+  segment_manager_main_t *smm = &sm_main;
+  fifo_segment_t *seg;
   segment_manager_t *sm;
   u8 show_segments = 0, verbose = 0;
   char *address;
@@ -782,15 +817,15 @@ segment_manager_show_fn (vlib_main_t * vm, unformat_input_t * input,
       /* *INDENT-OFF* */
       pool_foreach (sm, smm->segment_managers, ({
 	  segment_manager_foreach_segment_w_lock (seg, sm, ({
-	    svm_fifo_segment_info (seg, &address, &size);
-	    active_fifos = svm_fifo_segment_num_fifos (seg);
-	    free_fifos = svm_fifo_segment_num_free_fifos (seg, ~0 /* size */);
+	    fifo_segment_info (seg, &address, &size);
+	    active_fifos = fifo_segment_num_fifos (seg);
+	    free_fifos = fifo_segment_num_free_fifos (seg, ~0 /* size */);
 	    vlib_cli_output (vm, "%-15v%15U%15llu%15u%15u%15llx",
-			     ssvm_name (&seg->ssvm), format_svm_fifo_segment_type,
+			     ssvm_name (&seg->ssvm), format_fifo_segment_type,
 			     seg, size >> 20ULL, active_fifos, free_fifos,
 			     address);
 	    if (verbose)
-	      vlib_cli_output (vm, "%U", format_svm_fifo_segment, seg, verbose);
+	      vlib_cli_output (vm, "%U", format_fifo_segment, seg, verbose);
 	  }));
       }));
       /* *INDENT-ON* */
@@ -808,6 +843,66 @@ VLIB_CLI_COMMAND (segment_manager_show_command, static) =
 };
 /* *INDENT-ON* */
 
+void
+segment_manager_format_sessions (segment_manager_t * sm, int verbose)
+{
+  fifo_segment_t *fifo_segment;
+  vlib_main_t *vm = vlib_get_main ();
+  app_worker_t *app_wrk;
+  const u8 *app_name;
+  u8 *s = 0;
+
+  if (!sm)
+    {
+      if (verbose)
+	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
+			 "API Client", "SegManager");
+      else
+	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
+      return;
+    }
+
+  app_wrk = app_worker_get (sm->app_wrk_index);
+  app_name = application_name_from_index (app_wrk->app_index);
+
+  clib_rwlock_reader_lock (&sm->segments_rwlock);
+
+  /* *INDENT-OFF* */
+  pool_foreach (fifo_segment, sm->segments, ({
+    svm_fifo_t *fifo;
+    u8 *str;
+
+    fifo = fifo_segment_get_fifo_list (fifo_segment);
+    while (fifo)
+      {
+        u32 session_index, thread_index;
+        session_t *session;
+
+        session_index = fifo->master_session_index;
+        thread_index = fifo->master_thread_index;
+
+        session = session_get (session_index, thread_index);
+        str = format (0, "%U", format_session, session, verbose);
+
+        if (verbose)
+          s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
+                      app_wrk->api_client_index, app_wrk->connects_seg_manager);
+        else
+          s = format (s, "%-40s%-20s", str, app_name);
+
+        vlib_cli_output (vm, "%v", s);
+        vec_reset_length (s);
+        vec_free (str);
+
+        fifo = fifo->next;
+      }
+    vec_free (s);
+  }));
+  /* *INDENT-ON* */
+
+  clib_rwlock_reader_unlock (&sm->segments_rwlock);
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vnet/session/segment_manager.h b/src/vnet/session/segment_manager.h
index 2b6f43feba7..4f30b7a8d2c 100644
--- a/src/vnet/session/segment_manager.h
+++ b/src/vnet/session/segment_manager.h
@@ -15,14 +15,12 @@
 #ifndef SRC_VNET_SESSION_SEGMENT_MANAGER_H_
 #define SRC_VNET_SESSION_SEGMENT_MANAGER_H_
 
-#include <vnet/vnet.h>
-#include <svm/svm_fifo_segment.h>
 #include <svm/message_queue.h>
-#include <vlibmemory/api.h>
 #include <vppinfra/lock.h>
 #include <vppinfra/valloc.h>
+#include <svm/fifo_segment.h>
 
-typedef struct _segment_manager_properties
+typedef struct _segment_manager_props
 {
   u32 rx_fifo_size;			/**< receive fifo size */
   u32 tx_fifo_size;			/**< transmit fifo size */
@@ -35,12 +33,12 @@ typedef struct _segment_manager_properties
   u8 reserved:6;			/**< reserved flags */
   ssvm_segment_type_t segment_type;	/**< seg type: if set to SSVM_N_TYPES,
 					     private segments are used */
-} segment_manager_properties_t;
+} segment_manager_props_t;
 
 typedef struct _segment_manager
 {
   /** Pool of segments allocated by this manager */
-  svm_fifo_segment_private_t *segments;
+  fifo_segment_t *segments;
 
   /** rwlock that protects the segments pool */
   clib_rwlock_t segments_rwlock;
@@ -61,25 +59,6 @@ typedef struct _segment_manager
   svm_msg_q_t *event_queue;
 } segment_manager_t;
 
-#define segment_manager_foreach_segment_w_lock(VAR, SM, BODY)		\
-do {									\
-    clib_rwlock_reader_lock (&(SM)->segments_rwlock);			\
-    pool_foreach((VAR), ((SM)->segments), (BODY));			\
-    clib_rwlock_reader_unlock (&(SM)->segments_rwlock);			\
-} while (0)
-
-typedef struct segment_manager_main_
-{
-  /** Pool of segment managers */
-  segment_manager_t *segment_managers;
-
-  /** Virtual address allocator */
-  clib_valloc_main_t va_allocator;
-
-} segment_manager_main_t;
-
-extern segment_manager_main_t segment_manager_main;
-
 typedef struct segment_manager_main_init_args_
 {
   u64 baseva;
@@ -88,86 +67,78 @@ typedef struct segment_manager_main_init_args_
 
 #define SEGMENT_MANAGER_INVALID_APP_INDEX ((u32) ~0)
 
-/** Pool of segment managers */
-extern segment_manager_t *segment_managers;
-
-always_inline segment_manager_t *
-segment_manager_get (u32 index)
-{
-  return pool_elt_at_index (segment_manager_main.segment_managers, index);
-}
-
-always_inline segment_manager_t *
-segment_manager_get_if_valid (u32 index)
-{
-  if (pool_is_free_index (segment_manager_main.segment_managers, index))
-    return 0;
-  return pool_elt_at_index (segment_manager_main.segment_managers, index);
-}
-
-always_inline u32
-segment_manager_index (segment_manager_t * sm)
-{
-  return sm - segment_manager_main.segment_managers;
-}
-
-always_inline svm_msg_q_t *
-segment_manager_event_queue (segment_manager_t * sm)
-{
-  return sm->event_queue;
-}
-
-always_inline u64
-segment_manager_make_segment_handle (u32 segment_manager_index,
-				     u32 segment_index)
-{
-  return (((u64) segment_manager_index << 32) | segment_index);
-}
-
-u64 segment_manager_segment_handle (segment_manager_t * sm,
-				    svm_fifo_segment_private_t * segment);
-
-segment_manager_t *segment_manager_new ();
+segment_manager_t *segment_manager_alloc (void);
 int segment_manager_init (segment_manager_t * sm, u32 first_seg_size,
 			  u32 prealloc_fifo_pairs);
 
-svm_fifo_segment_private_t *segment_manager_get_segment (segment_manager_t *,
-							 u32 segment_index);
-svm_fifo_segment_private_t *segment_manager_get_segment_w_handle (u64);
-svm_fifo_segment_private_t
-  * segment_manager_get_segment_w_lock (segment_manager_t * sm,
-					u32 segment_index);
+/**
+ * Cleanup segment manager
+ *
+ * @param sm	segment manager to be freed
+ */
+void segment_manager_free (segment_manager_t * sm);
+
+/**
+ * Initiate segment manager cleanup
+ *
+ * @param sm	segment manager to be freed
+ */
+void segment_manager_init_free (segment_manager_t * sm);
+segment_manager_t *segment_manager_get (u32 index);
+segment_manager_t *segment_manager_get_if_valid (u32 index);
+u32 segment_manager_index (segment_manager_t * sm);
+
 int segment_manager_add_segment (segment_manager_t * sm, u32 segment_size);
 void segment_manager_del_segment (segment_manager_t * sm,
-				  svm_fifo_segment_private_t * fs);
+				  fifo_segment_t * fs);
+fifo_segment_t *segment_manager_get_segment (segment_manager_t * sm,
+					     u32 segment_index);
+fifo_segment_t *segment_manager_get_segment_w_handle (u64 sh);
+fifo_segment_t *segment_manager_get_segment_w_lock (segment_manager_t *,
+						    u32 segment_index);
+int segment_manager_add_first_segment (segment_manager_t * sm,
+				       u32 segment_size);
+u64 segment_manager_make_segment_handle (u32 segment_manager_index,
+					 u32 segment_index);
+u64 segment_manager_segment_handle (segment_manager_t * sm,
+				    fifo_segment_t * segment);
 void segment_manager_segment_reader_unlock (segment_manager_t * sm);
 void segment_manager_segment_writer_unlock (segment_manager_t * sm);
 
-int segment_manager_add_first_segment (segment_manager_t * sm,
-				       u32 segment_size);
-void segment_manager_del_sessions (segment_manager_t * sm);
-void segment_manager_del (segment_manager_t * sm);
-void segment_manager_init_del (segment_manager_t * sm);
-u8 segment_manager_has_fifos (segment_manager_t * sm);
 int segment_manager_alloc_session_fifos (segment_manager_t * sm,
-					 svm_fifo_t ** server_rx_fifo,
-					 svm_fifo_t ** server_tx_fifo);
-int segment_manager_try_alloc_fifos (svm_fifo_segment_private_t * fs,
+					 svm_fifo_t ** rx_fifo,
+					 svm_fifo_t ** tx_fifo);
+int segment_manager_try_alloc_fifos (fifo_segment_t * fs,
 				     u32 rx_fifo_size, u32 tx_fifo_size,
 				     svm_fifo_t ** rx_fifo,
 				     svm_fifo_t ** tx_fifo);
 void segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo,
 				    svm_fifo_t * tx_fifo);
-u32 segment_manager_evt_q_expected_size (u32 q_size);
-svm_msg_q_t *segment_manager_alloc_queue (svm_fifo_segment_private_t * fs,
-					  segment_manager_properties_t *
-					  props);
+u8 segment_manager_has_fifos (segment_manager_t * sm);
+
+svm_msg_q_t *segment_manager_alloc_queue (fifo_segment_t * fs,
+					  segment_manager_props_t * props);
 void segment_manager_dealloc_queue (segment_manager_t * sm, svm_queue_t * q);
+svm_msg_q_t *segment_manager_event_queue (segment_manager_t * sm);
+u32 segment_manager_evt_q_expected_size (u32 q_size);
+
 void segment_manager_app_detach (segment_manager_t * sm);
 
+/**
+ * Cleanup segment manager sessions
+ *
+ * Initiates disconnects for all sessions 'owned' by a segment manager by
+ * leveraging the backpointers that fifos keep.
+ *
+ * @param sm	segment manager whose sessions are to be disconnected
+ */
+void segment_manager_del_sessions (segment_manager_t * sm);
+void segment_manager_format_sessions (segment_manager_t * sm, int verbose);
+
 void segment_manager_main_init (segment_manager_main_init_args_t * a);
-segment_manager_properties_t
-  * segment_manager_properties_init (segment_manager_properties_t * sm);
+
+segment_manager_props_t *segment_manager_props_init (segment_manager_props_t *
+						     sm);
 
 #endif /* SRC_VNET_SESSION_SEGMENT_MANAGER_H_ */
 /*
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 0a7781f2876..83af125946e 100755
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -83,8 +83,8 @@ send_add_segment_callback (u32 api_client_index, u64 segment_handle)
 {
   int fds[SESSION_N_FD_TYPE], n_fds = 0;
   vl_api_map_another_segment_t *mp;
-  svm_fifo_segment_private_t *fs;
   vl_api_registration_t *reg;
+  fifo_segment_t *fs;
   ssvm_private_t *sp;
   u8 fd_flags = 0;