Tenure allocation sites only when semi-space is maximum size.

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 1559 matching lines @@
 }
 
 
 inline void AllocationSite::IncrementMementoCreateCount() {
   ASSERT(FLAG_allocation_site_pretenuring);
   int value = memento_create_count();
   set_memento_create_count(value + 1);
 }
 
 
-inline bool AllocationSite::DigestPretenuringFeedback() {
-  bool decision_changed = false;
+inline bool AllocationSite::MakePretenureDecision(
+    PretenureDecision current_decision,
+    double ratio,
+    bool maximum_size_scavenge) {
+  // Here we just allow state transitions from undecided or maybe tenure
+  // to don't tenure, maybe tenure, or tenure.
+  if ((current_decision == kUndecided || current_decision == kMaybeTenure)) {
+    if (ratio >= kPretenureRatio) {
+      // We just transition into tenure state when the semi-space was at
+      // maximum capacity.
+      if (maximum_size_scavenge) {
+        set_deopt_dependent_code(true);
+        set_pretenure_decision(kTenure);
+        // Currently we just need to deopt when we make a state transition to
+        // tenure.
+        return true;
+      }
+      set_pretenure_decision(kMaybeTenure);
+    } else {
+      set_pretenure_decision(kDontTenure);
+    }
+  }
+  return false;
+}
+
+
+inline bool AllocationSite::DigestPretenuringFeedback(
+    bool maximum_size_scavenge) {
+  bool deopt = false;
   int create_count = memento_create_count();
   int found_count = memento_found_count();
   bool minimum_mementos_created = create_count >= kPretenureMinimumCreated;
   double ratio =
       minimum_mementos_created || FLAG_trace_pretenuring_statistics ?
           static_cast<double>(found_count) / create_count : 0.0;
-  PretenureFlag current_mode = GetPretenureMode();
+  PretenureDecision current_decision = pretenure_decision();
 
-  // TODO(hpayer): Add an intermediate state MAYBE_TENURE which collects
-  // more lifetime feedback for tenuring candidates. In the meantime, we
-  // just allow transitions from undecided to tenured or not tenured.
-  if (minimum_mementos_created && pretenure_decision() == kUndecided) {
-    PretenureDecision result = ratio >= kPretenureRatio
-        ? kTenure
-        : kDontTenure;
-    set_pretenure_decision(result);
-    if (current_mode != GetPretenureMode()) {
-      decision_changed = true;
-      set_deopt_dependent_code(true);
-    }
+  if (minimum_mementos_created) {
+    deopt = MakePretenureDecision(
+        current_decision, ratio, maximum_size_scavenge);
   }
 
   if (FLAG_trace_pretenuring_statistics) {
     PrintF(
         "AllocationSite(%p): (created, found, ratio) (%d, %d, %f) %s => %s\n",
          static_cast<void*>(this), create_count, found_count, ratio,
-         current_mode == TENURED ? "tenured" : "not tenured",
-         GetPretenureMode() == TENURED ? "tenured" : "not tenured");
+         PretenureDecisionName(current_decision),
+         PretenureDecisionName(pretenure_decision()));
   }
 
   // Clear feedback calculation fields until the next gc.
   set_memento_found_count(0);
   set_memento_create_count(0);
-  return decision_changed;
+  return deopt;
 }
 
 
 void JSObject::EnsureCanContainHeapObjectElements(Handle<JSObject> object) {
   JSObject::ValidateElements(object);
   ElementsKind elements_kind = object->map()->elements_kind();
   if (!IsFastObjectElementsKind(elements_kind)) {
     if (IsFastHoleyElementsKind(elements_kind)) {
       TransitionElementsKind(object, FAST_HOLEY_ELEMENTS);
     } else {
@@ skipping 5243 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_