1. Add code to grow the heap instead of collecting garbage in Heap::AllocateOld when allocation is …

runtime/vm/heap.h

Index: runtime/vm/heap.h
diff --git a/runtime/vm/heap.h b/runtime/vm/heap.h
index 2ef3e3cd5d422ddd3f5bcae781cd496032435a07..4a8ae93afaacae64b41fc6437de10ee313139bac 100644
--- a/runtime/vm/heap.h
+++ b/runtime/vm/heap.h
@@ -125,6 +125,9 @@ class Heap {
   void CollectGarbage(Space space);
   void CollectGarbage(Space space, ApiCallbacks api_callbacks, GCReason reason);
   void CollectAllGarbage();
+  bool NeedsGarbageCollection() const {
+    return old_space_.NeedsGarbageCollection();
+  }
 
   // Enables growth control on the page space heaps.  This should be
   // called before any user code is executed.
@@ -231,8 +234,6 @@ class Heap {
     stats_.data_[id] = value;
   }
 
-  bool gc_in_progress();
-
   void UpdateGlobalMaxUsed();
 
   static bool IsAllocatableInNewSpace(intptr_t size) {
@@ -308,16 +309,24 @@ class Heap {
   // ensure thread-safety.
   bool VerifyGC(MarkExpectation mark_expectation = kForbidMarked) const;
 
+  // Helper functions for garbage collection.
+  void CollectNewSpaceGarbage(
+      Thread* thread, ApiCallbacks api_callbacks, GCReason reason);
+  void CollectOldSpaceGarbage(
+      Thread* thread, ApiCallbacks api_callbacks, GCReason reason);
+
   // GC stats collection.
   void RecordBeforeGC(Space space, GCReason reason);
-  void RecordAfterGC();
+  void RecordAfterGC(Space space);
   void PrintStats();
   void UpdateClassHeapStatsBeforeGC(Heap::Space space);
   void UpdatePretenurePolicy();
 
-  // Updates gc_in_progress.
-  void BeginGC();
-  void EndGC();
+  // Updates gc in progress flags.
+  bool BeginNewSpaceGC();
+  void EndNewSpaceGC();
+  bool BeginOldSpaceGC();
+  void EndOldSpaceGC();
 
   // If this heap is non-empty, updates start and end to the smallest range that
   // contains both the original [start, end) and the [lowest, highest) addresses
@@ -340,8 +349,9 @@ class Heap {
   bool read_only_;
 
   // GC on the heap is in progress.
-  Mutex gc_in_progress_mutex_;
-  bool gc_in_progress_;
+  Monitor gc_in_progress_monitor_;
+  bool gc_new_space_in_progress_;
+  bool gc_old_space_in_progress_;
 
   int pretenure_policy_;