session: async rx event notifications

Move from synchronous flushing of io and ctrl events from transports to
applications to an async model via a new session_input input node that
runs in interrupt mode. Events are coalesced per application worker.

On the one hand, this helps by minimizing message queue locking churn.
And on the other, it opens the possibility for further optimizations of
event message generation, obviates need for rx rescheduling rpcs and is
a first step towards a fully async data/io rx path.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Id6bebcb65fc9feef8aa02ddf1af6d9ba6f6745ce

1 files changed, 28 insertions, 12 deletions

diff --git a/src/vnet/session/application_local.c b/src/vnet/session/application_local.c
index 6ac4da2c655..192c22b659a 100644
--- a/src/vnet/session/application_local.c
+++ b/src/vnet/session/application_local.c
@@ -1028,6 +1028,17 @@ ct_close_is_reset (ct_connection_t *ct, session_t *s)
 }
 
 static void
+ct_session_cleanup_server_session (session_t *s)
+{
+  ct_connection_t *ct;
+
+  ct = (ct_connection_t *) session_get_transport (s);
+  ct_session_dealloc_fifos (ct, s->rx_fifo, s->tx_fifo);
+  session_free (s);
+  ct_connection_free (ct);
+}
+
+static void
 ct_session_postponed_cleanup (ct_connection_t *ct)
 {
   ct_connection_t *peer_ct;
@@ -1047,33 +1058,38 @@ ct_session_postponed_cleanup (ct_connection_t *ct)
     }
   session_transport_closed_notify (&ct->connection);
 
+  /* It would be cleaner to call session_transport_delete_notify
+   * but then we can't control session cleanup lower */
+  session_set_state (s, SESSION_STATE_TRANSPORT_DELETED);
+  if (app_wrk)
+    app_worker_cleanup_notify (app_wrk, s, SESSION_CLEANUP_TRANSPORT);
+
   if (ct->flags & CT_CONN_F_CLIENT)
     {
-      if (app_wrk)
-	app_worker_cleanup_notify (app_wrk, s, SESSION_CLEANUP_TRANSPORT);
-
       /* Normal free for client session as the fifos are allocated through
        * the connects segment manager in a segment that's not shared with
        * the server */
       ct_session_dealloc_fifos (ct, ct->client_rx_fifo, ct->client_tx_fifo);
-      session_free_w_fifos (s);
+      session_program_cleanup (s);
+      ct_connection_free (ct);
     }
   else
     {
       /* Manual session and fifo segment cleanup to avoid implicit
        * segment manager cleanups and notifications */
-      app_wrk = app_worker_get_if_valid (s->app_wrk_index);
       if (app_wrk)
 	{
-	  app_worker_cleanup_notify (app_wrk, s, SESSION_CLEANUP_TRANSPORT);
-	  app_worker_cleanup_notify (app_wrk, s, SESSION_CLEANUP_SESSION);
+	  /* Remove custom cleanup notify infra when/if switching to normal
+	   * session cleanup. Note that ct is freed in the cb function */
+	  app_worker_cleanup_notify_custom (app_wrk, s,
+					    SESSION_CLEANUP_SESSION,
+					    ct_session_cleanup_server_session);
+	}
+      else
+	{
+	  ct_connection_free (ct);
 	}
-
-      ct_session_dealloc_fifos (ct, s->rx_fifo, s->tx_fifo);
-      session_free (s);
     }
-
-  ct_connection_free (ct);
 }
 
 static void