GC. Delay/avoid entering high promotion mode

src/heap/heap.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 99 matching lines @@
       idle_old_generation_allocation_limit_(
           kMinimumOldGenerationAllocationLimit),
       old_gen_exhausted_(false),
       inline_allocation_disabled_(false),
       store_buffer_rebuilder_(store_buffer()),
       hidden_string_(NULL),
       gc_safe_size_of_old_object_(NULL),
       total_regexp_code_generated_(0),
       tracer_(this),
       new_space_high_promotion_mode_active_(false),
+      gathering_lifetime_feedback_(0),
       high_survival_rate_period_length_(0),
       promoted_objects_size_(0),
       low_survival_rate_period_length_(0),
       survival_rate_(0),
       promotion_ratio_(0),
       semi_space_copied_object_size_(0),
       previous_semi_space_copied_object_size_(0),
       semi_space_copied_rate_(0),
       nodes_died_in_new_space_(0),
       nodes_copied_in_new_space_(0),
@@ skipping 1116 matching lines @@
     old_generation_size_at_last_gc_ = PromotedSpaceSizeOfObjects();
   } else {
     Scavenge();
   }
 
   bool deopted = ProcessPretenuringFeedback();
   UpdateSurvivalStatistics(start_new_space_size);
 
   // When pretenuring is collecting new feedback, we do not shrink the new space
   // right away.
-  if (!deopted) {
+  if (deopted) {
+    RecordDeoptForPretenuring();
+  } else {
     ConfigureNewGenerationSize();
   }
   ConfigureInitialOldGenerationSize();
 
   isolate_->counters()->objs_since_last_young()->Set(0);
 
   if (collector != SCAVENGER) {
     // Callbacks that fire after this point might trigger nested GCs and
     // restart incremental marking, the assertion can't be moved down.
     DCHECK(incremental_marking()->IsStopped());
@@ skipping 1361 matching lines @@
     old_generation_allocation_limit_ =
         Max(kMinimumOldGenerationAllocationLimit,
             static_cast<intptr_t>(
                 static_cast<double>(old_generation_allocation_limit_) *
                 (tracer()->AverageSurvivalRatio() / 100)));
   }
 }
 
 
 void Heap::ConfigureNewGenerationSize() {
+  bool still_gathering_lifetime_data = gathering_lifetime_feedback_ != 0;
+  if (gathering_lifetime_feedback_ != 0) gathering_lifetime_feedback_--;
   if (!new_space_high_promotion_mode_active_ &&
       new_space_.TotalCapacity() == new_space_.MaximumCapacity() &&
       IsStableOrIncreasingSurvivalTrend() && IsHighSurvivalRate()) {
     // Stable high survival rates even though young generation is at
     // maximum capacity indicates that most objects will be promoted.
     // To decrease scavenger pauses and final mark-sweep pauses, we
     // have to limit maximal capacity of the young generation.
-    new_space_high_promotion_mode_active_ = true;
-    if (FLAG_trace_gc) {
-      PrintPID("Limited new space size due to high promotion rate: %d MB\n",
-               new_space_.InitialTotalCapacity() / MB);
+    if (still_gathering_lifetime_data) {
+      if (FLAG_trace_gc) {
+        PrintPID(
+            "Postpone entering high promotion mode as optimized pretenuring "
+            "code is still being generated\n");
+      }
+    } else {
+      new_space_high_promotion_mode_active_ = true;
+      if (FLAG_trace_gc) {
+        PrintPID("Limited new space size due to high promotion rate: %d MB\n",
+                 new_space_.InitialTotalCapacity() / MB);
+      }
     }
   } else if (new_space_high_promotion_mode_active_ &&
              IsStableOrDecreasingSurvivalTrend() && IsLowSurvivalRate()) {
     // Decreasing low survival rates might indicate that the above high
     // promotion mode is over and we should allow the young generation
     // to grow again.
     new_space_high_promotion_mode_active_ = false;
     if (FLAG_trace_gc) {
       PrintPID("Unlimited new space size due to low promotion rate: %d MB\n",
                new_space_.MaximumCapacity() / MB);
@@ skipping 4189 matching lines @@
     *object_type = "CODE_TYPE";                                                \
     *object_sub_type = "CODE_AGE/" #name;                                      \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 }  // namespace internal
 }  // namespace v8