session: connects seg manager is always first

By convention, connects segment manager will be first. Therefore it will
be the one with the first segment wherein lies the app's message queue.

Saves us the trouble of allocating it on first connect, if app started
by listening, and we no longer need to track if it's assignable to a
listener or if it can be removed.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Iba9a8ffaab618eeb41ec2144dcfee62d006dc7a2

3 files changed, 23 insertions, 77 deletions

diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index 2f6bfa97892..8abec7797ec 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -1008,7 +1008,7 @@ application_alloc_worker_and_init (application_t * app, app_worker_t ** wrk)
   /*
    * Setup app worker
    */
-  app_wrk->first_segment_manager = segment_manager_index (sm);
+  app_wrk->connects_seg_manager = segment_manager_index (sm);
   app_wrk->listeners_table = hash_create (0, sizeof (u64));
   app_wrk->event_queue = segment_manager_event_queue (sm);
   app_wrk->app_is_builtin = application_is_builtin (app);
@@ -1041,7 +1041,7 @@ vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
       app_wrk->api_client_index = a->api_client_index;
       application_api_table_add (app->app_index, a->api_client_index);
 
-      sm = segment_manager_get (app_wrk->first_segment_manager);
+      sm = segment_manager_get (app_wrk->connects_seg_manager);
       fs = segment_manager_get_segment_w_lock (sm, 0);
       a->segment = &fs->ssvm;
       a->segment_handle = segment_manager_segment_handle (sm, fs);
@@ -1157,7 +1157,7 @@ vnet_application_attach (vnet_app_attach_args_t * a)
 
   a->app_evt_q = app_wrk->event_queue;
   app_wrk->api_client_index = a->api_client_index;
-  sm = segment_manager_get (app_wrk->first_segment_manager);
+  sm = segment_manager_get (app_wrk->connects_seg_manager);
   fs = segment_manager_get_segment_w_lock (sm, 0);
 
   if (application_is_proxy (app))
@@ -1165,7 +1165,7 @@ vnet_application_attach (vnet_app_attach_args_t * a)
       application_setup_proxy (app);
       /* The segment manager pool is reallocated because a new listener
        * is added. Re-grab segment manager to avoid dangling reference */
-      sm = segment_manager_get (app_wrk->first_segment_manager);
+      sm = segment_manager_get (app_wrk->connects_seg_manager);
     }
 
   ASSERT (vec_len (fs->ssvm.name) <= 128);
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index 0bfd4d1d813..a8ddfec07f5 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -45,20 +45,17 @@ typedef struct app_worker_
   /** Application listens for events on this svm queue */
   svm_msg_q_t *event_queue;
 
-  /** Segment manager used for outgoing connects issued by the app */
+  /**
+   * Segment manager used for outgoing connects issued by the app. By
+   * convention this is the first segment manager allocated by the worker
+   * so it's also the one that holds the first segment with the app's
+   * message queue in it.
+   */
   u32 connects_seg_manager;
 
   /** Lookup tables for listeners. Value is segment manager index */
   uword *listeners_table;
 
-  /**
-   * First segment manager has in the the first segment the application's
-   * event fifo. Depending on what the app does, it may be either used for
-   * a listener or for connects.
-   */
-  u32 first_segment_manager;
-  u8 first_segment_manager_in_use;
-
   /** API index for the worker. Needed for multi-process apps */
   u32 api_client_index;
 
@@ -339,9 +336,6 @@ int app_worker_session_fifo_tuning (app_worker_t * app_wrk, session_t * s,
 segment_manager_t *app_worker_get_listen_segment_manager (app_worker_t *,
 							  session_t *);
 segment_manager_t *app_worker_get_connect_segment_manager (app_worker_t *);
-segment_manager_t
-  * app_worker_get_or_alloc_connect_segment_manager (app_worker_t *);
-int app_worker_alloc_connects_segment_manager (app_worker_t * app);
 int app_worker_add_segment_notify (app_worker_t * app_wrk,
 				   u64 segment_handle);
 int app_worker_del_segment_notify (app_worker_t * app_wrk,
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 8c3be22d4dc..7e03171b115 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -32,7 +32,6 @@ app_worker_alloc (application_t * app)
   app_wrk->app_index = app->app_index;
   app_wrk->wrk_map_index = ~0;
   app_wrk->connects_seg_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
-  app_wrk->first_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
   clib_spinlock_init (&app_wrk->detached_seg_managers_lock);
   APP_DBG ("New app %v worker %u", app->name, app_wrk->wrk_index);
   return app_wrk;
@@ -143,17 +142,6 @@ app_worker_free (app_worker_t * app_wrk)
   vec_free (app_wrk->detached_seg_managers);
   clib_spinlock_free (&app_wrk->detached_seg_managers_lock);
 
-  /* If first segment manager is used by a listener that recently
-   * stopped listening, mark it as detached */
-  if (app_wrk->first_segment_manager != app_wrk->connects_seg_manager
-      && (sm = segment_manager_get_if_valid (app_wrk->first_segment_manager))
-      && !segment_manager_app_detached (sm))
-    {
-      sm->first_is_protected = 0;
-      sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
-      segment_manager_init_free (sm);
-    }
-
   if (CLIB_DEBUG)
     clib_memset (app_wrk, 0xfe, sizeof (*app_wrk));
   pool_put (app_workers, app_wrk);
@@ -172,19 +160,9 @@ app_worker_get_app (u32 wrk_index)
 static segment_manager_t *
 app_worker_alloc_segment_manager (app_worker_t * app_wrk)
 {
-  segment_manager_t *sm = 0;
+  segment_manager_t *sm;
 
-  /* If the first segment manager is not in use, don't allocate a new one */
-  if (app_wrk->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
-      && app_wrk->first_segment_manager_in_use == 0)
-    {
-      sm = segment_manager_get (app_wrk->first_segment_manager);
-      app_wrk->first_segment_manager_in_use = 1;
-    }
-  else
-    {
-      sm = segment_manager_alloc ();
-    }
+  sm = segment_manager_alloc ();
   sm->app_wrk_index = app_wrk->wrk_index;
   segment_manager_init (sm);
   return sm;
@@ -309,20 +287,21 @@ app_worker_stop_listen_session (app_worker_t * app_wrk, session_t * ls)
 
   /* Try to cleanup segment manager */
   sm = segment_manager_get (*sm_indexp);
-  if (sm && segment_manager_has_fifos (sm))
-    {
-      /* Delete sessions in CREATED state */
-      vec_add1 (states, SESSION_STATE_CREATED);
-      segment_manager_del_sessions_filter (sm, states);
-      vec_free (states);
-    }
-  if (sm && app_wrk->first_segment_manager != *sm_indexp)
+  if (sm)
     {
       segment_manager_app_detach (sm);
       if (!segment_manager_has_fifos (sm))
-	segment_manager_free (sm);
+	{
+	  /* Empty segment manager, cleanup it up */
+	  segment_manager_free (sm);
+	}
       else
 	{
+	  /* Delete sessions in CREATED state */
+	  vec_add1 (states, SESSION_STATE_CREATED);
+	  segment_manager_del_sessions_filter (sm, states);
+	  vec_free (states);
+
 	  /* Track segment manager in case app detaches and all the
 	   * outstanding sessions need to be closed */
 	  app_worker_add_detached_sm (app_wrk, *sm_indexp);
@@ -534,7 +513,7 @@ app_worker_own_session (app_worker_t * app_wrk, session_t * s)
   s->rx_fifo = 0;
   s->tx_fifo = 0;
 
-  sm = app_worker_get_or_alloc_connect_segment_manager (app_wrk);
+  sm = app_worker_get_connect_segment_manager (app_wrk);
   if (app_worker_alloc_session_fifos (sm, s))
     return -1;
 
@@ -555,10 +534,6 @@ app_worker_connect_session (app_worker_t * app_wrk, session_endpoint_t * sep,
 {
   int rv;
 
-  /* Make sure we have a segment manager for connects */
-  if (app_worker_alloc_connects_segment_manager (app_wrk))
-    return SESSION_E_ALLOC;
-
   if ((rv = session_open (app_wrk->wrk_index, sep, api_context)))
     return rv;
 
@@ -574,21 +549,6 @@ app_worker_session_fifo_tuning (app_worker_t * app_wrk, session_t * s,
   return app->cb_fns.fifo_tuning_callback (s, f, act, len);
 }
 
-int
-app_worker_alloc_connects_segment_manager (app_worker_t * app_wrk)
-{
-  segment_manager_t *sm;
-
-  if (app_wrk->connects_seg_manager == APP_INVALID_SEGMENT_MANAGER_INDEX)
-    {
-      sm = app_worker_alloc_segment_manager (app_wrk);
-      if (sm == 0)
-	return -1;
-      app_wrk->connects_seg_manager = segment_manager_index (sm);
-    }
-  return 0;
-}
-
 segment_manager_t *
 app_worker_get_connect_segment_manager (app_worker_t * app)
 {
@@ -597,14 +557,6 @@ app_worker_get_connect_segment_manager (app_worker_t * app)
 }
 
 segment_manager_t *
-app_worker_get_or_alloc_connect_segment_manager (app_worker_t * app_wrk)
-{
-  if (app_wrk->connects_seg_manager == (u32) ~ 0)
-    app_worker_alloc_connects_segment_manager (app_wrk);
-  return segment_manager_get (app_wrk->connects_seg_manager);
-}
-
-segment_manager_t *
 app_worker_get_listen_segment_manager (app_worker_t * app,
 				       session_t * listener)
 {