[NOT FOR LANDING] Patch for experiments: V8

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index c4a1baa6d38acac0a66323c79da10afb8134ca92..26df0f7275357ace876a8c59ea8c013ce53fd970 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -814,7 +814,10 @@ void Heap::FinalizeIncrementalMarking(GarbageCollectionReason gc_reason) {
       TRACE_GC(tracer(), GCTracer::Scope::MC_INCREMENTAL_EXTERNAL_PROLOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
-      CallGCPrologueCallbacks(kGCTypeIncrementalMarking, kNoGCCallbackFlags);
+      CallGCPrologueCallbacks(kGCTypeIncrementalMarking,
+          FLAG_object_grouping_in_incremental_finalization
+              ? kNoGCCallbackFlags
+              : kGCCallbackFlagDisableObjectGrouping);
     }
   }
   incremental_marking()->FinalizeIncrementally();
@@ -5411,16 +5414,6 @@ bool Heap::ShouldOptimizeForLoadTime() {
 // - or the incremental marking is not in progress and we cannot start it.
 bool Heap::ShouldExpandOldGenerationOnSlowAllocation() {
   if (always_allocate() || OldGenerationSpaceAvailable() > 0) return true;
-  // We reached the old generation allocation limit.

[ulan, 2017/03/30 16:24:30]

This changes reduce noise in scheduling mark-compact GCs.

-
-  if (ShouldOptimizeForMemoryUsage()) return false;
-
-  if (ShouldOptimizeForLoadTime()) return true;
-
-  if (incremental_marking()->NeedsFinalization()) {
-    return !AllocationLimitOvershotByLargeMargin();
-  }
-
   if (incremental_marking()->IsStopped() &&
       IncrementalMarkingLimitReached() == IncrementalMarkingLimit::kNoLimit) {
     // We cannot start incremental marking.
@@ -5451,12 +5444,6 @@ Heap::IncrementalMarkingLimit Heap::IncrementalMarkingLimitReached() {
   if (old_generation_space_available > new_space_->Capacity()) {
     return IncrementalMarkingLimit::kNoLimit;
   }
-  if (ShouldOptimizeForMemoryUsage()) {

[ulan, 2017/03/30 16:24:30]

This changes reduce noise in scheduling mark-compact GCs.

-    return IncrementalMarkingLimit::kHardLimit;
-  }
-  if (ShouldOptimizeForLoadTime()) {
-    return IncrementalMarkingLimit::kNoLimit;
-  }
   if (old_generation_space_available == 0) {
     return IncrementalMarkingLimit::kHardLimit;
   }