Perform smaller marking steps incrementally in idle notification.

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 4471 matching lines @@
 
   bool result = false;
   switch (action.type) {
     case DONE:
       result = true;
       break;
     case DO_INCREMENTAL_MARKING: {
       if (incremental_marking()->IsStopped()) {
         incremental_marking()->Start();
       }
-      incremental_marking()->Step(action.parameter,
-                                  IncrementalMarking::NO_GC_VIA_STACK_GUARD,
-                                  IncrementalMarking::FORCE_MARKING,
-                                  IncrementalMarking::DO_NOT_FORCE_COMPLETION);
-      double remaining_idle_time_in_ms =
-          deadline_in_ms - MonotonicallyIncreasingTimeInMs();
+      double remaining_idle_time_in_ms = 0.0;
+      do {
+        incremental_marking()->Step(
+            action.parameter, IncrementalMarking::NO_GC_VIA_STACK_GUARD,
+            IncrementalMarking::FORCE_MARKING,
+            IncrementalMarking::DO_NOT_FORCE_COMPLETION);
+        remaining_idle_time_in_ms =
+            deadline_in_ms - MonotonicallyIncreasingTimeInMs();
+      } while (remaining_idle_time_in_ms >=
+                   2.0 * GCIdleTimeHandler::kIncrementalMarkingStepTimeInMs &&
+               !incremental_marking()->IsComplete() &&
+               !mark_compact_collector_.marking_deque()->IsEmpty());
       if (remaining_idle_time_in_ms > 0.0) {
         TryFinalizeIdleIncrementalMarking(
             remaining_idle_time_in_ms, heap_state.size_of_objects,
             heap_state.final_incremental_mark_compact_speed_in_bytes_per_ms);
       }
       break;
     }
     case DO_FULL_GC: {
       if (contexts_disposed_) {
         HistogramTimerScope scope(isolate_->counters()->gc_context());
@@ skipping 1862 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal