Fragmented young heap generation and off_heap_message_queue option

* The youngest generation of the heap can now consist of multiple
  blocks. Heap fragments and message fragments are added to the
  youngest generation when needed without triggering a GC. After
  a GC the youngest generation is contained in one single block.
* The off_heap_message_queue process flag has been added. When
  enabled all message data in the queue is kept off heap. When
  a message is selected from the queue, the message fragment (or
  heap fragment) containing the actual message is attached to the
  youngest generation. Messages stored off heap is not part of GC.

1 files changed, 10 insertions, 7 deletions

diff --git a/erts/emulator/beam/erl_bif_ddll.c b/erts/emulator/beam/erl_bif_ddll.c
index 28bec6325c..2b1d875bfe 100644
--- a/erts/emulator/beam/erl_bif_ddll.c
+++ b/erts/emulator/beam/erl_bif_ddll.c
@@ -1707,18 +1707,19 @@ static void notify_proc(Process *proc, Eterm ref, Eterm driver_name, Eterm type,
     Eterm mess;
     Eterm r;
     Eterm *hp;
-    ErlHeapFragment *bp;
-    ErlOffHeap *ohp;
+    ErtsMessage *mp;
     ErtsProcLocks rp_locks = 0;
+    ErlOffHeap *ohp;
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 
     assert_drv_list_rwlocked();
     if (errcode != 0) {
 	int need = load_error_need(errcode);
 	Eterm e;
-	hp = erts_alloc_message_heap(6 /* tuple */ + 3 /* Error tuple */ + 
-				     REF_THING_SIZE + need, &bp, &ohp, 
-				     proc, &rp_locks);
+	mp = erts_alloc_message_heap(proc, &rp_locks,
+				     (6 /* tuple */ + 3 /* Error tuple */ + 
+				      REF_THING_SIZE + need),
+				     &hp, &ohp);
 	r = copy_ref(ref,hp);
 	hp += REF_THING_SIZE;
 	e = build_load_error_hp(hp, errcode);
@@ -1727,12 +1728,14 @@ static void notify_proc(Process *proc, Eterm ref, Eterm driver_name, Eterm type,
 	hp += 3;
 	mess = TUPLE5(hp,type,r,am_driver,driver_name,mess);
     } else {	
-	hp = erts_alloc_message_heap(6 /* tuple */ + REF_THING_SIZE, &bp, &ohp, proc, &rp_locks);
+	mp = erts_alloc_message_heap(proc, &rp_locks,
+				     6 /* tuple */ + REF_THING_SIZE,
+				     &hp, &ohp);
 	r = copy_ref(ref,hp);
 	hp += REF_THING_SIZE;
 	mess = TUPLE5(hp,type,r,am_driver,driver_name,tag);
     }
-    erts_queue_message(proc, &rp_locks, bp, mess, am_undefined);
+    erts_queue_message(proc, &rp_locks, mp, mess, am_undefined);
     erts_smp_proc_unlock(proc, rp_locks);
     ERTS_SMP_CHK_NO_PROC_LOCKS;
 }