From 3ac08f9b668613a4292436979eacc61863c2ab94 Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Wed, 16 Sep 2015 15:02:50 +0200
Subject: 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.
---
 erts/emulator/beam/dist.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

(limited to 'erts/emulator/beam/dist.c')

diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index efd5109269..bfddcadca3 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -373,10 +373,11 @@ static void doit_node_link_net_exits(ErtsLink *lnk, void *vnecp)
     ASSERT(lnk->type == LINK_NODE);
     if (is_internal_pid(lnk->pid)) {
 	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
-	rp = erts_pid2proc(NULL, 0, lnk->pid, rp_locks);
-	if (!rp) {
+	ErlOffHeap *ohp;
+	rp = erts_proc_lookup(lnk->pid);
+	if (!rp)
 	    goto done;
-	}
+	erts_smp_proc_lock(rp, rp_locks);
 	rlnk = erts_remove_link(&ERTS_P_LINKS(rp), name);
 	if (rlnk != NULL) {
 	    ASSERT(is_atom(rlnk->pid) && (rlnk->type == LINK_NODE));
@@ -384,12 +385,14 @@ static void doit_node_link_net_exits(ErtsLink *lnk, void *vnecp)
 	}
 	n = ERTS_LINK_REFC(lnk);
 	for (i = 0; i < n; ++i) {
-	    ErlHeapFragment* bp;
-	    ErlOffHeap *ohp;
 	    Eterm tup;
-	    Eterm *hp = erts_alloc_message_heap(3,&bp,&ohp,rp,&rp_locks);
+	    Eterm *hp;
+	    ErtsMessage *msgp;
+
+	    msgp = erts_alloc_message_heap(rp, &rp_locks,
+					   3, &hp, &ohp);
 	    tup = TUPLE2(hp, am_nodedown, name);
-	    erts_queue_message(rp, &rp_locks, bp, tup, NIL);
+	    erts_queue_message(rp, &rp_locks, msgp, tup, NIL);
 	}
 	erts_smp_proc_unlock(rp, rp_locks);
     }
@@ -1458,7 +1461,7 @@ int erts_net_message(Port *prt,
 		ErlOffHeap *ohp;
 		ASSERT(xsize);
 		heap_frag = erts_dist_ext_trailer(ede_copy);
-		ERTS_INIT_HEAP_FRAG(heap_frag, token_size);
+		ERTS_INIT_HEAP_FRAG(heap_frag, token_size, token_size);
 		hp = heap_frag->mem;
 		ohp = &heap_frag->off_heap;
 		token = tuple[5];
@@ -1507,7 +1510,7 @@ int erts_net_message(Port *prt,
 		ErlOffHeap *ohp;
 		ASSERT(xsize);
 		heap_frag = erts_dist_ext_trailer(ede_copy);
-		ERTS_INIT_HEAP_FRAG(heap_frag, token_size);
+		ERTS_INIT_HEAP_FRAG(heap_frag, token_size, token_size);
 		hp = heap_frag->mem;
 		ohp = &heap_frag->off_heap;
 		token = tuple[4];
@@ -3267,11 +3270,16 @@ send_nodes_mon_msg(Process *rp,
 		   Uint sz)
 {
     Eterm msg;
-    ErlHeapFragment* bp;
+    Eterm *hp;
+    ErtsMessage *mp;
     ErlOffHeap *ohp;
-    Eterm *hp = erts_alloc_message_heap(sz, &bp, &ohp, rp, rp_locksp);
 #ifdef DEBUG
-    Eterm *hend = hp + sz;
+    Eterm *hend;
+#endif
+
+    mp = erts_alloc_message_heap(rp, rp_locksp, sz, &hp, &ohp);
+#ifdef DEBUG
+    hend = hp + sz;
 #endif
 
     if (!nmp->opts) {
@@ -3317,7 +3325,7 @@ send_nodes_mon_msg(Process *rp,
     }
 
     ASSERT(hend == hp);
-    erts_queue_message(rp, rp_locksp, bp, msg, NIL);
+    erts_queue_message(rp, rp_locksp, mp, msg, NIL);
 }
 
 static void
-- 
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