session/tcp: improve preallocated segment handling

- add preallocated segment flag
- don't remove pre-allocated segments except if application detaches
- when preallocating fifos in multiple segments, completely fill
  a segment before moving to the next
- detach server application from segment-managers when deleting app
- batch syn/syn-ack/fin (re)transmissions
- loosen up close-wait and time-wait times

Change-Id: I412f53ce601cc83b3acc26aeffd7fa2d52d73b03
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 40 insertions, 33 deletions

diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index c23e4c0237c..48d027553b1 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -197,27 +197,24 @@ u8
 segment_manager_has_fifos (segment_manager_t * sm)
 {
   svm_fifo_segment_private_t *segment;
-  /* Weird, but handle it */
-  if (vec_len (sm->segment_indices) == 0)
-    return 0;
-  if (vec_len (sm->segment_indices) == 1)
-    {
-      segment = svm_fifo_segment_get_segment (sm->segment_indices[0]);
-      if (svm_fifo_segment_num_fifos (segment) == 0)
-	return 0;
-    }
-  if (CLIB_DEBUG)
+  int i;
+
+  for (i = 0; i < vec_len (sm->segment_indices); i++)
     {
-      svm_fifo_segment_private_t *segment;
-      int i;
-      for (i = 1; i < vec_len (sm->segment_indices); i++)
-	{
-	  segment = svm_fifo_segment_get_segment (sm->segment_indices[i]);
-	  if (!svm_fifo_segment_has_fifos (segment))
-	    clib_warning ("segment has no fifos!");
-	}
+      segment = svm_fifo_segment_get_segment (sm->segment_indices[i]);
+      if (CLIB_DEBUG && i && !svm_fifo_segment_has_fifos (segment)
+	  && !(segment->h->flags & FIFO_SEGMENT_F_IS_PREALLOCATED))
+	clib_warning ("segment %d has no fifos!", sm->segment_indices[i]);
+      if (svm_fifo_segment_has_fifos (segment))
+	return 1;
     }
-  return 1;
+  return 0;
+}
+
+static u8
+segment_manager_app_detached (segment_manager_t * sm)
+{
+  return (sm->app_index == SEGMENT_MANAGER_INVALID_APP_INDEX);
 }
 
 static void
@@ -228,6 +225,13 @@ segment_manager_del_segment (segment_manager_t * sm, u32 segment_index)
   clib_spinlock_lock (&sm->lockp);
   svm_segment_index = sm->segment_indices[segment_index];
   fifo_segment = svm_fifo_segment_get_segment (svm_segment_index);
+  if (!fifo_segment
+      || ((fifo_segment->h->flags & FIFO_SEGMENT_F_IS_PREALLOCATED)
+	  && !segment_manager_app_detached (sm)))
+    {
+      clib_spinlock_unlock (&sm->lockp);
+      return;
+    }
   svm_fifo_segment_delete (fifo_segment);
   vec_del1 (sm->segment_indices, segment_index);
   clib_spinlock_unlock (&sm->lockp);
@@ -288,26 +292,29 @@ segment_manager_del_sessions (segment_manager_t * sm)
  *
  * Since the fifos allocated in the segment keep backpointers to the sessions
  * prior to removing the segment, we call session disconnect. This
- * subsequently propages into transport.
+ * subsequently propagates into transport.
  */
 void
 segment_manager_del (segment_manager_t * sm)
 {
+  int i;
 
-  ASSERT (vec_len (sm->segment_indices) <= 1);
-  if (vec_len (sm->segment_indices))
+  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. */
+  for (i = vec_len (sm->segment_indices) - 1; i >= 0; i--)
     {
-      /* 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. */
       if (CLIB_DEBUG)
 	{
-	  svm_fifo_segment_private_t *fifo_segment;
-	  fifo_segment =
-	    svm_fifo_segment_get_segment (sm->segment_indices[0]);
-	  ASSERT (!svm_fifo_segment_has_fifos (fifo_segment));
+	  svm_fifo_segment_private_t *segment;
+	  segment = svm_fifo_segment_get_segment (sm->segment_indices[i]);
+	  ASSERT (!svm_fifo_segment_has_fifos (segment));
 	}
-      segment_manager_del_segment (sm, 0);
+      segment_manager_del_segment (sm, i);
     }
   clib_spinlock_free (&sm->lockp);
   if (CLIB_DEBUG)
@@ -322,8 +329,7 @@ segment_manager_init_del (segment_manager_t * sm)
     segment_manager_del_sessions (sm);
   else
     {
-      ASSERT (!sm->first_is_protected
-	      || sm->app_index == SEGMENT_MANAGER_INVALID_APP_INDEX);
+      ASSERT (!sm->first_is_protected || segment_manager_app_detached (sm));
       segment_manager_del (sm);
     }
 }
@@ -478,7 +484,8 @@ segment_manager_dealloc_fifos (u32 svm_segment_index, svm_fifo_t * rx_fifo,
 	}
 
       /* Remove segment manager if no sessions and detached from app */
-      if (sm->app_index == SEGMENT_MANAGER_INVALID_APP_INDEX && is_first)
+      if (segment_manager_app_detached (sm)
+	  && !segment_manager_has_fifos (sm))
 	segment_manager_del (sm);
     }
 }