Immediatelly promote marked objects

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index ea25bdb69869208c12021b3c6ba1bf4e663efd56..b82490c06844c7fa835b540afd37db858b4aece3 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1599,7 +1599,15 @@ class ScavengeWeakObjectRetainer : public WeakObjectRetainer {
   Heap* heap_;
 };
 
+void Heap::Scavenge() {
+  if (incremental_marking()->IsMarking()) {
+    Scavenge<PROMOTE_MARKED>();
+  } else {
+    Scavenge<DEFAULT_PROMOTION>();
+  }
+}
 
+template <PromotionMode promotion_mode>
 void Heap::Scavenge() {

[ulan, 2016/05/30 16:09:06]

Wdyt about detemplatizing this functoin and making the promotion_mode a local
variable?

   TRACE_GC(tracer(), GCTracer::Scope::SCAVENGER_SCAVENGE);
   RelocationLock relocation_lock(this);
@@ -1653,7 +1661,7 @@ void Heap::Scavenge() {
   Address new_space_front = new_space_.ToSpaceStart();
   promotion_queue_.Initialize();
 
-  ScavengeVisitor scavenge_visitor(this);
+  ScavengeVisitor<promotion_mode> scavenge_visitor(this);

[ulan, 2016/05/30 16:09:06]

If we make the promotion mode a field of ScavengeVisitor, then we can
detemplatize this function.

 
   if (FLAG_scavenge_reclaim_unmodified_objects) {
     isolate()->global_handles()->IdentifyWeakUnmodifiedObjects(
@@ -1670,7 +1678,7 @@ void Heap::Scavenge() {
     // Copy objects reachable from the old generation.
     TRACE_GC(tracer(), GCTracer::Scope::SCAVENGER_OLD_TO_NEW_POINTERS);
     RememberedSet<OLD_TO_NEW>::Iterate(this, [this](Address addr) {
-      return Scavenger::CheckAndScavengeObject(this, addr, DEFAULT_PROMOTION);
+      return Scavenger::CheckAndScavengeObject<promotion_mode>(this, addr);
     });
 
     RememberedSet<OLD_TO_NEW>::IterateTyped(
@@ -1680,8 +1688,8 @@ void Heap::Scavenge() {
                 // We expect that objects referenced by code are long living.
                 // If we do not force promotion, then we need to clear
                 // old_to_new slots in dead code objects after mark-compact.
-                return Scavenger::CheckAndScavengeObject(
-                    this, reinterpret_cast<Address>(addr), FORCE_PROMOTION);
+                return Scavenger::CheckAndScavengeObject<promotion_mode>(
+                    this, reinterpret_cast<Address>(addr));
               });
         });
   }
@@ -1705,7 +1713,8 @@ void Heap::Scavenge() {
 
   {
     TRACE_GC(tracer(), GCTracer::Scope::SCAVENGER_SEMISPACE);
-    new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+    new_space_front =
+        DoScavenge<promotion_mode>(&scavenge_visitor, new_space_front);
   }
 
   if (FLAG_scavenge_reclaim_unmodified_objects) {
@@ -1714,12 +1723,14 @@ void Heap::Scavenge() {
 
     isolate()->global_handles()->IterateNewSpaceWeakUnmodifiedRoots(
         &scavenge_visitor);
-    new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+    new_space_front =
+        DoScavenge<promotion_mode>(&scavenge_visitor, new_space_front);
   } else {
     TRACE_GC(tracer(), GCTracer::Scope::SCAVENGER_OBJECT_GROUPS);
     while (isolate()->global_handles()->IterateObjectGroups(
         &scavenge_visitor, &IsUnscavengedHeapObject)) {
-      new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+      new_space_front =
+          DoScavenge<promotion_mode>(&scavenge_visitor, new_space_front);
     }
     isolate()->global_handles()->RemoveObjectGroups();
     isolate()->global_handles()->RemoveImplicitRefGroups();
@@ -1729,7 +1740,8 @@ void Heap::Scavenge() {
 
     isolate()->global_handles()->IterateNewSpaceWeakIndependentRoots(
         &scavenge_visitor);
-    new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+    new_space_front =
+        DoScavenge<promotion_mode>(&scavenge_visitor, new_space_front);
   }
 
   UpdateNewSpaceReferencesInExternalStringTable(
@@ -1911,7 +1923,7 @@ void Heap::VisitExternalResources(v8::ExternalResourceVisitor* visitor) {
   external_string_table_.Iterate(&external_string_table_visitor);
 }
 
-
+template <PromotionMode promotion_mode>
 Address Heap::DoScavenge(ObjectVisitor* scavenge_visitor,
                          Address new_space_front) {

[ulan, 2016/05/30 16:09:06]

How about making promotion_mode a parameter of the function?

   do {
@@ -1922,8 +1934,8 @@ Address Heap::DoScavenge(ObjectVisitor* scavenge_visitor,
     while (new_space_front != new_space_.top()) {
       if (!Page::IsAlignedToPageSize(new_space_front)) {
         HeapObject* object = HeapObject::FromAddress(new_space_front);
-        new_space_front +=
-            StaticScavengeVisitor::IterateBody(object->map(), object);
+        new_space_front += StaticScavengeVisitor<promotion_mode>::IterateBody(
+            object->map(), object);
       } else {
         new_space_front = Page::FromAllocationAreaAddress(new_space_front)
                               ->next_page()
@@ -1946,7 +1958,7 @@ Address Heap::DoScavenge(ObjectVisitor* scavenge_visitor,
         DCHECK(!target->IsMap());
 
         IteratePromotedObject(target, static_cast<int>(size), was_marked_black,
-                              &Scavenger::ScavengeObject);
+                              &Scavenger::ScavengeObject<promotion_mode>);
       }
     }
 
@@ -4689,8 +4701,8 @@ void Heap::IteratePromotedObjectPointers(HeapObject* object, Address start,
     Object* target = *slot;
     if (target->IsHeapObject()) {
       if (Heap::InFromSpace(target)) {
-        callback(reinterpret_cast<HeapObject**>(slot), HeapObject::cast(target),
-                 DEFAULT_PROMOTION);
+        callback(reinterpret_cast<HeapObject**>(slot),
+                 HeapObject::cast(target));
         Object* new_target = *slot;
         if (InNewSpace(new_target)) {
           SLOW_DCHECK(Heap::InToSpace(new_target));
@@ -5232,7 +5244,8 @@ V8_DECLARE_ONCE(initialize_gc_once);
 
 static void InitializeGCOnce() {
   Scavenger::Initialize();
-  StaticScavengeVisitor::Initialize();
+  StaticScavengeVisitor<DEFAULT_PROMOTION>::Initialize();
+  StaticScavengeVisitor<PROMOTE_MARKED>::Initialize();
   MarkCompactCollector::Initialize();
 }