Reland "Replace reduce-memory mode in idle notification with delayed clean-up GC."

test/unittests/heap/gc-idle-time-handler-unittest.cc

 // Copyright 2014 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 <limits>
 
 #include "src/heap/gc-idle-time-handler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
 namespace internal {
 
 namespace {
 
 class GCIdleTimeHandlerTest : public ::testing::Test {
  public:
   GCIdleTimeHandlerTest() {}
   virtual ~GCIdleTimeHandlerTest() {}
 
   GCIdleTimeHandler* handler() { return &handler_; }
 
   GCIdleTimeHandler::HeapState DefaultHeapState() {
     GCIdleTimeHandler::HeapState result;
     result.contexts_disposed = 0;
     result.contexts_disposal_rate = GCIdleTimeHandler::kHighContextDisposalRate;
     result.size_of_objects = kSizeOfObjects;
     result.incremental_marking_stopped = false;
-    result.can_start_incremental_marking = true;
     result.sweeping_in_progress = false;
     result.sweeping_completed = false;
     result.mark_compact_speed_in_bytes_per_ms = kMarkCompactSpeed;
     result.incremental_marking_speed_in_bytes_per_ms = kMarkingSpeed;
     result.scavenge_speed_in_bytes_per_ms = kScavengeSpeed;
     result.used_new_space_size = 0;
     result.new_space_capacity = kNewSpaceCapacity;
     result.new_space_allocation_throughput_in_bytes_per_ms =
         kNewSpaceAllocationThroughput;
     return result;
   }
 
-  void TransitionToReduceMemoryMode(
-      const GCIdleTimeHandler::HeapState& heap_state) {
-    handler()->NotifyScavenge();
-    EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-    double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-    int limit = GCIdleTimeHandler::kLongIdleNotificationsBeforeMutatorIsIdle;
-    bool incremental = !heap_state.incremental_marking_stopped ||
-                       heap_state.can_start_incremental_marking;
-    for (int i = 0; i < limit; i++) {
-      GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-      if (incremental) {
-        EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-      } else {
-        EXPECT_TRUE(DO_NOTHING == action.type || DONE == action.type);
-      }
-    }
-    handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-  }
-
-  void TransitionToDoneMode(const GCIdleTimeHandler::HeapState& heap_state,
-                            double idle_time_ms,
-                            GCIdleTimeActionType expected) {
-    EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-    int limit = GCIdleTimeHandler::kMaxIdleMarkCompacts;
-    for (int i = 0; i < limit; i++) {
-      GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-      EXPECT_EQ(expected, action.type);
-      EXPECT_TRUE(action.reduce_memory);
-      handler()->NotifyMarkCompact(true);
-      handler()->NotifyIdleMarkCompact();
-    }
-    handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(GCIdleTimeHandler::kDone, handler()->mode());
-  }
-
-  void TransitionToReduceLatencyMode(
-      const GCIdleTimeHandler::HeapState& heap_state) {
-    EXPECT_EQ(GCIdleTimeHandler::kDone, handler()->mode());
-    int limit = GCIdleTimeHandler::kMarkCompactsBeforeMutatorIsActive;
-    double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-    for (int i = 0; i < limit; i++) {
-      GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-      EXPECT_EQ(DONE, action.type);
-      handler()->NotifyMarkCompact(true);
-    }
-    handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-  }
-
   static const size_t kSizeOfObjects = 100 * MB;
   static const size_t kMarkCompactSpeed = 200 * KB;
   static const size_t kMarkingSpeed = 200 * KB;
   static const size_t kScavengeSpeed = 100 * KB;
   static const size_t kNewSpaceCapacity = 1 * MB;
   static const size_t kNewSpaceAllocationThroughput = 10 * KB;
-  static const int kMaxNotifications = 1000;
+  static const int kMaxNotifications = 100;
 
  private:
   GCIdleTimeHandler handler_;
 };
 
 }  // namespace
 
 
 TEST(GCIdleTimeHandler, EstimateMarkingStepSizeInitial) {
   size_t step_size = GCIdleTimeHandler::EstimateMarkingStepSize(1, 0);
@@ skipping 148 matching lines @@
   EXPECT_FALSE(GCIdleTimeHandler::ShouldDoFinalIncrementalMarkCompact(
       idle_time_ms, kSizeOfObjects, kMarkingSpeed));
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, ContextDisposeLowRate) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.contexts_disposed = 1;
   heap_state.incremental_marking_stopped = true;
   double idle_time_ms = 0;
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_NOTHING, action.type);
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_NOTHING, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, ContextDisposeHighRate) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.contexts_disposed = 1;
   heap_state.contexts_disposal_rate =
       GCIdleTimeHandler::kHighContextDisposalRate - 1;
   heap_state.incremental_marking_stopped = true;
   double idle_time_ms = 0;
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_FULL_GC, action.type);
-    heap_state.contexts_disposal_rate = 0.0;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_FULL_GC, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeZeroIdleTime) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.contexts_disposed = 1;
   heap_state.contexts_disposal_rate = 1.0;
   heap_state.incremental_marking_stopped = true;
   double idle_time_ms = 0;
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_FULL_GC, action.type);
-    heap_state.contexts_disposal_rate = 0.0;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_FULL_GC, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeSmallIdleTime1) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.contexts_disposed = 1;
   heap_state.contexts_disposal_rate =
       GCIdleTimeHandler::kHighContextDisposalRate;
-  heap_state.incremental_marking_stopped = true;
   size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
   double idle_time_ms =
       static_cast<double>(heap_state.size_of_objects / speed - 1);
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    heap_state.contexts_disposal_rate = 0.0;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeSmallIdleTime2) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.contexts_disposed = 1;
   heap_state.contexts_disposal_rate =
       GCIdleTimeHandler::kHighContextDisposalRate;
   size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
   double idle_time_ms =
       static_cast<double>(heap_state.size_of_objects / speed - 1);
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    heap_state.contexts_disposal_rate = 0.0;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, IncrementalMarking1) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   size_t speed = heap_state.incremental_marking_speed_in_bytes_per_ms;
   double idle_time_ms = 10;
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
-              static_cast<size_t>(action.parameter));
-    EXPECT_LT(0, action.parameter);
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+  EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
+            static_cast<size_t>(action.parameter));
+  EXPECT_LT(0, action.parameter);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, IncrementalMarking2) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
   size_t speed = heap_state.incremental_marking_speed_in_bytes_per_ms;
   double idle_time_ms = 10;
-  for (int mode = 0; mode < 1; mode++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
-              static_cast<size_t>(action.parameter));
-    EXPECT_LT(0, action.parameter);
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+  EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
+            static_cast<size_t>(action.parameter));
+  EXPECT_LT(0, action.parameter);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, NotEnoughTime) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
   size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
   double idle_time_ms =
       static_cast<double>(heap_state.size_of_objects / speed - 1);
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_NOTHING, action.type);
-  TransitionToReduceMemoryMode(heap_state);
-  action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+  EXPECT_EQ(DONE, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, FinalizeSweeping) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  for (int mode = 0; mode < 1; mode++) {
-    heap_state.sweeping_in_progress = true;
-    heap_state.sweeping_completed = true;
-    double idle_time_ms = 10.0;
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_FINALIZE_SWEEPING, action.type);
-    heap_state.sweeping_in_progress = false;
-    heap_state.sweeping_completed = false;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  heap_state.sweeping_in_progress = true;
+  heap_state.sweeping_completed = true;
+  double idle_time_ms = 10.0;
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_FINALIZE_SWEEPING, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, CannotFinalizeSweeping) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  for (int mode = 0; mode < 1; mode++) {
-    heap_state.sweeping_in_progress = true;
-    heap_state.sweeping_completed = false;
-    double idle_time_ms = 10.0;
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_NOTHING, action.type);
-    heap_state.sweeping_in_progress = false;
-    heap_state.sweeping_completed = false;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  heap_state.sweeping_in_progress = true;
+  heap_state.sweeping_completed = false;
+  double idle_time_ms = 10.0;
+  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_NOTHING, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, Scavenge) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   int idle_time_ms = 10;
-  for (int mode = 0; mode < 1; mode++) {
-    heap_state.used_new_space_size =
-        heap_state.new_space_capacity -
-        (kNewSpaceAllocationThroughput * idle_time_ms);
-    GCIdleTimeAction action =
-        handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
-    EXPECT_EQ(DO_SCAVENGE, action.type);
-    heap_state.used_new_space_size = 0;
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  heap_state.used_new_space_size =
+      heap_state.new_space_capacity -
+      (kNewSpaceAllocationThroughput * idle_time_ms);
+  GCIdleTimeAction action =
+      handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
+  EXPECT_EQ(DO_SCAVENGE, action.type);
+  heap_state.used_new_space_size = 0;
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, ScavengeAndDone) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   int idle_time_ms = 10;
-  heap_state.can_start_incremental_marking = false;
   heap_state.incremental_marking_stopped = true;
-  for (int mode = 0; mode < 1; mode++) {
-    heap_state.used_new_space_size =
-        heap_state.new_space_capacity -
-        (kNewSpaceAllocationThroughput * idle_time_ms);
-    GCIdleTimeAction action =
-        handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
-    EXPECT_EQ(DO_SCAVENGE, action.type);
-    heap_state.used_new_space_size = 0;
-    action = handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
-    EXPECT_EQ(DO_NOTHING, action.type);
-    TransitionToReduceMemoryMode(heap_state);
-  }
+  heap_state.used_new_space_size =
+      heap_state.new_space_capacity -
+      (kNewSpaceAllocationThroughput * idle_time_ms);
+  GCIdleTimeAction action =
+      handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
+  EXPECT_EQ(DO_SCAVENGE, action.type);
+  heap_state.used_new_space_size = 0;
+  action = handler()->Compute(static_cast<double>(idle_time_ms), heap_state);
+  EXPECT_EQ(DONE, action.type);
 }
 
 
-TEST_F(GCIdleTimeHandlerTest, StopEventually1) {
+TEST_F(GCIdleTimeHandlerTest, DoNotStartIncrementalMarking) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  bool stopped = false;
-  for (int i = 0; i < kMaxNotifications && !stopped; i++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    if (action.type == DO_INCREMENTAL_MARKING || action.type == DO_FULL_GC) {
-      handler()->NotifyMarkCompact(true);
-      handler()->NotifyIdleMarkCompact();
-    }
-    if (action.type == DONE) stopped = true;
-  }
-  EXPECT_TRUE(stopped);
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, StopEventually2) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
-  double idle_time_ms =
-      static_cast<double>(heap_state.size_of_objects / speed + 1);
-  TransitionToReduceMemoryMode(heap_state);
-  TransitionToDoneMode(heap_state, idle_time_ms, DO_FULL_GC);
+  double idle_time_ms = 10.0;
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
   EXPECT_EQ(DONE, action.type);
 }
 
 
-TEST_F(GCIdleTimeHandlerTest, StopEventually3) {
+TEST_F(GCIdleTimeHandlerTest, ContinueAfterStop) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = 10;
-  TransitionToReduceMemoryMode(heap_state);
-  TransitionToDoneMode(heap_state, idle_time_ms, DO_INCREMENTAL_MARKING);
+  double idle_time_ms = 10.0;
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
   EXPECT_EQ(DONE, action.type);
+  heap_state.incremental_marking_stopped = false;
+  action = handler()->Compute(idle_time_ms, heap_state);
+  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
 }
 
 
-TEST_F(GCIdleTimeHandlerTest, ContinueAfterStop1) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
-  double idle_time_ms =
-      static_cast<double>(heap_state.size_of_objects / speed + 1);
-  TransitionToReduceMemoryMode(heap_state);
-  TransitionToDoneMode(heap_state, idle_time_ms, DO_FULL_GC);
-  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DONE, action.type);
-  TransitionToReduceLatencyMode(heap_state);
-  heap_state.can_start_incremental_marking = true;
-  action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-  EXPECT_FALSE(action.reduce_memory);
-  EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, ContinueAfterStop2) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = 10;
-  TransitionToReduceMemoryMode(heap_state);
-  TransitionToDoneMode(heap_state, idle_time_ms, DO_INCREMENTAL_MARKING);
-  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DONE, action.type);
-  TransitionToReduceLatencyMode(heap_state);
-  heap_state.can_start_incremental_marking = true;
-  action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-  EXPECT_FALSE(action.reduce_memory);
-  EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-}
-
-
 TEST_F(GCIdleTimeHandlerTest, ZeroIdleTimeNothingToDo) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   for (int i = 0; i < kMaxNotifications; i++) {
     GCIdleTimeAction action = handler()->Compute(0, heap_state);
     EXPECT_EQ(DO_NOTHING, action.type);
   }
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, SmallIdleTimeNothingToDo) {
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
   for (int i = 0; i < kMaxNotifications; i++) {
     GCIdleTimeAction action = handler()->Compute(10, heap_state);
     EXPECT_TRUE(DO_NOTHING == action.type || DONE == action.type);
   }
 }
 
 
-TEST_F(GCIdleTimeHandlerTest, StayInReduceLatencyModeBecauseOfScavenges) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  int limit = GCIdleTimeHandler::kLongIdleNotificationsBeforeMutatorIsIdle;
-  for (int i = 0; i < kMaxNotifications; i++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_TRUE(DO_NOTHING == action.type || DONE == action.type);
-    if ((i + 1) % limit == 0) handler()->NotifyScavenge();
-    EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-  }
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, StayInReduceLatencyModeBecauseOfMarkCompacts) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  int limit = GCIdleTimeHandler::kLongIdleNotificationsBeforeMutatorIsIdle;
-  for (int i = 0; i < kMaxNotifications; i++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_TRUE(DO_NOTHING == action.type || DONE == action.type);
-    if ((i + 1) % limit == 0) handler()->NotifyMarkCompact(true);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-  }
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, ReduceMemoryToReduceLatency) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  int limit = GCIdleTimeHandler::kMaxIdleMarkCompacts;
-  for (int idle_gc = 0; idle_gc < limit; idle_gc++) {
-    TransitionToReduceMemoryMode(heap_state);
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    EXPECT_TRUE(action.reduce_memory);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-    for (int i = 0; i < idle_gc; i++) {
-      action = handler()->Compute(idle_time_ms, heap_state);
-      EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-      EXPECT_TRUE(action.reduce_memory);
-      // ReduceMemory mode should tolerate one mutator GC per idle GC.
-      handler()->NotifyScavenge();
-      // Notify idle GC.
-      handler()->NotifyMarkCompact(true);
-      handler()->NotifyIdleMarkCompact();
-    }
-    // Transition to ReduceLatency mode after doing |idle_gc| idle GCs.
-    handler()->NotifyScavenge();
-    action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_NOTHING, action.type);
-    EXPECT_FALSE(action.reduce_memory);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-  }
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, ReduceMemoryToDone) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  int limit = GCIdleTimeHandler::kMaxIdleMarkCompacts;
-  TransitionToReduceMemoryMode(heap_state);
-  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-  EXPECT_TRUE(action.reduce_memory);
-  for (int i = 0; i < limit; i++) {
-    action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-    EXPECT_TRUE(action.reduce_memory);
-    EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-    // ReduceMemory mode should tolerate one mutator GC per idle GC.
-    handler()->NotifyScavenge();
-    // Notify idle GC.
-    handler()->NotifyMarkCompact(true);
-    handler()->NotifyIdleMarkCompact();
-  }
-  action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DONE, action.type);
-}
-
-
 TEST_F(GCIdleTimeHandlerTest, DoneIfNotMakingProgressOnSweeping) {
   // Regression test for crbug.com/489323.
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
 
   // Simulate sweeping being in-progress but not complete.
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
   heap_state.sweeping_in_progress = true;
   heap_state.sweeping_completed = false;
   double idle_time_ms = 10.0;
-  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerMode; i++) {
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimes; i++) {
     GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
     EXPECT_EQ(DO_NOTHING, action.type);
   }
   // We should return DONE after not making progress for some time.
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
   EXPECT_EQ(DONE, action.type);
 }
 
 
 TEST_F(GCIdleTimeHandlerTest, DoneIfNotMakingProgressOnIncrementalMarking) {
   // Regression test for crbug.com/489323.
   GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
 
   // Simulate incremental marking stopped and not eligible to start.
   heap_state.incremental_marking_stopped = true;
-  heap_state.can_start_incremental_marking = false;
   double idle_time_ms = 10.0;
-  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerMode; i++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_NOTHING, action.type);
-  }
-  // We should return DONE after not making progress for some time.
+  // We should return DONE if we cannot start incremental marking.
   GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
   EXPECT_EQ(DONE, action.type);
 }
 
-
-TEST_F(GCIdleTimeHandlerTest, BackgroundReduceLatencyToReduceMemory) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = false;
-  heap_state.can_start_incremental_marking = true;
-  double idle_time_ms = GCIdleTimeHandler::kMinBackgroundIdleTime;
-  handler()->NotifyScavenge();
-  EXPECT_EQ(GCIdleTimeHandler::kReduceLatency, handler()->mode());
-  int limit =
-      GCIdleTimeHandler::kBackgroundIdleNotificationsBeforeMutatorIsIdle;
-  for (int i = 0; i < limit; i++) {
-    GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-    EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-  }
-  handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-}
-
-
-TEST_F(GCIdleTimeHandlerTest, SkipUselessGCs) {
-  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
-  heap_state.incremental_marking_stopped = false;
-  heap_state.can_start_incremental_marking = true;
-  TransitionToReduceMemoryMode(heap_state);
-  EXPECT_EQ(GCIdleTimeHandler::kReduceMemory, handler()->mode());
-  double idle_time_ms = GCIdleTimeHandler::kMinLongIdleTime;
-  GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
-  handler()->NotifyMarkCompact(false);
-  handler()->NotifyIdleMarkCompact();
-  action = handler()->Compute(idle_time_ms, heap_state);
-  EXPECT_EQ(DONE, action.type);
-}
-
 }  // namespace internal
 }  // namespace v8