Version 4.3.61.2 (cherry-pick)

Merged 00477a5

Ensure that GC idle notifications either make progress or stop requesting more GCs.

BUG=chromium:470615
LOG=N
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/1071503002

Cr-Commit-Position: refs/branch-heads/4.3@{#3}
Cr-Branched-From: f5c0a23-refs/heads/4.3.61@{#1}
Cr-Branched-From: 0a7d4f4-refs/heads/master@{#27508}

include/v8-version.h

@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 4
 #define V8_MINOR_VERSION 3
 #define V8_BUILD_NUMBER 61
-#define V8_PATCH_LEVEL 1
+#define V8_PATCH_LEVEL 2
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)

src/heap/gc-idle-time-handler.cc

@@ -184,11 +184,22 @@ bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure(
 }
 
 
+GCIdleTimeAction GCIdleTimeHandler::NothingOrDone() {
+  if (idle_times_which_made_no_progress_since_last_idle_round_ >=
+      kMaxNoProgressIdleTimesPerIdleRound) {
+    return GCIdleTimeAction::Done();
+  } else {
+    idle_times_which_made_no_progress_since_last_idle_round_++;
+    return GCIdleTimeAction::Nothing();
+  }
+}
+
+
 // The following logic is implemented by the controller:
 // (1) If we don't have any idle time, do nothing, unless a context was
 // disposed, incremental marking is stopped, and the heap is small. Then do
 // a full GC.
-// (2) If the new space is almost full and we can affort a Scavenge or if the
+// (2) If the new space is almost full and we can afford a Scavenge or if the
 // next Scavenge will very likely take long, then a Scavenge is performed.
 // (3) If there is currently no MarkCompact idle round going on, we start a
 // new idle round if enough garbage was created. Otherwise we do not perform
@@ -249,8 +260,9 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
 
   if (heap_state.incremental_marking_stopped &&
       !heap_state.can_start_incremental_marking) {
-    return GCIdleTimeAction::Nothing();
+    return NothingOrDone();
   }
+
   size_t step_size = EstimateMarkingStepSize(
       static_cast<size_t>(kIncrementalMarkingStepTimeInMs),
       heap_state.incremental_marking_speed_in_bytes_per_ms);

src/heap/gc-idle-time-handler.h

@@ -138,6 +138,11 @@ class GCIdleTimeHandler {
 
   static const size_t kMinTimeForOverApproximatingWeakClosureInMs;
 
+  // Number of times we will return a Nothing action per Idle round despite
+  // having idle time available before we returning a Done action to ensure we
+  // don't keep scheduling idle tasks and making no progress.
+  static const int kMaxNoProgressIdleTimesPerIdleRound = 10;
+
   class HeapState {
    public:
     void Print();
@@ -159,7 +164,8 @@ class GCIdleTimeHandler {
 
   GCIdleTimeHandler()
       : mark_compacts_since_idle_round_started_(0),
-        scavenges_since_last_idle_round_(0) {}
+        scavenges_since_last_idle_round_(0),
+        idle_times_which_made_no_progress_since_last_idle_round_(0) {}
 
   GCIdleTimeAction Compute(double idle_time_in_ms, HeapState heap_state);
 
@@ -203,7 +209,12 @@ class GCIdleTimeHandler {
       size_t new_space_allocation_throughput_in_bytes_per_ms);
 
  private:
-  void StartIdleRound() { mark_compacts_since_idle_round_started_ = 0; }
+  GCIdleTimeAction NothingOrDone();
+
+  void StartIdleRound() {
+    mark_compacts_since_idle_round_started_ = 0;
+    idle_times_which_made_no_progress_since_last_idle_round_ = 0;
+  }
   bool IsMarkCompactIdleRoundFinished() {
     return mark_compacts_since_idle_round_started_ ==
            kMaxMarkCompactsInIdleRound;
@@ -214,6 +225,7 @@ class GCIdleTimeHandler {
 
   int mark_compacts_since_idle_round_started_;
   int scavenges_since_last_idle_round_;
+  int idle_times_which_made_no_progress_since_last_idle_round_;
 
   DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler);
 };

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

@@ -440,5 +440,55 @@ TEST_F(GCIdleTimeHandlerTest, ZeroIdleTimeDoNothingButStartIdleRound) {
   EXPECT_EQ(DO_NOTHING, action.type);
 }
 
+
+TEST_F(GCIdleTimeHandlerTest, KeepDoingDoNothingWithZeroIdleTime) {
+  GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerIdleRound;
+       i++) {
+    GCIdleTimeAction action = handler()->Compute(0, heap_state);
+    EXPECT_EQ(DO_NOTHING, action.type);
+  }
+  // Should still return DO_NOTHING if we have been given 0 deadline yet.
+  GCIdleTimeAction action = handler()->Compute(0, heap_state);
+  EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, DoneIfNotMakingProgressOnSweeping) {
+  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;
+  double idle_time_ms = 10.0;
+  for (int i = 0; i < GCIdleTimeHandler::kMaxNoProgressIdleTimesPerIdleRound;
+       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) {
+  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::kMaxNoProgressIdleTimesPerIdleRound;
+       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);
+}
+
 }  // namespace internal
 }  // namespace v8