Version 4.5.103.23 (cherry-pick)

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 757 matching lines @@
   }
   // We must not compact the weak fixed list here, as we may be in the middle
   // of writing to it, when the GC triggered. Instead, we reset the root value.
   set_weak_stack_trace_list(Smi::FromInt(0));
 }
 
 
 void Heap::HandleGCRequest() {
   if (incremental_marking()->request_type() ==
       IncrementalMarking::COMPLETE_MARKING) {
-    CollectAllGarbage(Heap::kNoGCFlags, "GC interrupt");
+    CollectAllGarbage(Heap::kNoGCFlags, "GC interrupt",
+                      incremental_marking()->CallbackFlags());
     return;
   }
   DCHECK(FLAG_overapproximate_weak_closure);
   if (!incremental_marking()->weak_closure_was_overapproximated()) {
     OverApproximateWeakClosure("GC interrupt");
   }
 }
 
 
 void Heap::OverApproximateWeakClosure(const char* gc_reason) {
@@ skipping 189 matching lines @@
   if (collector == MARK_COMPACTOR &&
       (gc_callback_flags & kGCCallbackFlagForced) != 0) {
     isolate()->CountUsage(v8::Isolate::kForcedGC);
   }
 
   // Start incremental marking for the next cycle. The heap snapshot
   // generator needs incremental marking to stay off after it aborted.
   if (!mark_compact_collector()->abort_incremental_marking() &&
       incremental_marking()->IsStopped() &&
       incremental_marking()->ShouldActivateEvenWithoutIdleNotification()) {
-    incremental_marking()->Start(kNoGCFlags);
+    incremental_marking()->Start(kNoGCFlags, kNoGCCallbackFlags, "GC epilogue");
   }
 
   return next_gc_likely_to_collect_more;
 }
 
 
 int Heap::NotifyContextDisposed(bool dependant_context) {
   if (!dependant_context) {
     tracer()->ResetSurvivalEvents();
     old_generation_size_configured_ = false;
   }
   if (isolate()->concurrent_recompilation_enabled()) {
     // Flush the queued recompilation tasks.
     isolate()->optimizing_compile_dispatcher()->Flush();
   }
   AgeInlineCaches();
   set_retained_maps(ArrayList::cast(empty_fixed_array()));
   tracer()->AddContextDisposalTime(base::OS::TimeCurrentMillis());
   MemoryReducer::Event event;
   event.type = MemoryReducer::kContextDisposed;
   event.time_ms = MonotonicallyIncreasingTimeInMs();
   memory_reducer_.NotifyContextDisposed(event);
   return ++contexts_disposed_;
 }
 
 
+void Heap::StartIncrementalMarking(int gc_flags,
+                                   const GCCallbackFlags gc_callback_flags,
+                                   const char* reason) {
+  DCHECK(incremental_marking()->IsStopped());
+  incremental_marking()->Start(gc_flags, gc_callback_flags, reason);
+}
+
+
 void Heap::StartIdleIncrementalMarking() {
   gc_idle_time_handler_.ResetNoProgressCounter();
-  incremental_marking()->Start(kReduceMemoryFootprintMask);
+  StartIncrementalMarking(kReduceMemoryFootprintMask, kNoGCCallbackFlags,
+                          "idle");
 }
 
 
 void Heap::MoveElements(FixedArray* array, int dst_index, int src_index,
                         int len) {
   if (len == 0) return;
 
   DCHECK(array->map() != fixed_cow_array_map());
   Object** dst_objects = array->data_start() + dst_index;
   MemMove(dst_objects, array->data_start() + src_index, len * kPointerSize);
@@ skipping 3727 matching lines @@
   if (!IsHeapIterable()) {
     CollectAllGarbage(kMakeHeapIterableMask, "Heap::MakeHeapIterable");
   }
   if (mark_compact_collector()->sweeping_in_progress()) {
     mark_compact_collector()->EnsureSweepingCompleted();
   }
   DCHECK(IsHeapIterable());
 }
 
 
+static double ComputeMutatorUtilization(double mutator_speed, double gc_speed) {
+  const double kMinMutatorUtilization = 0.0;
+  const double kConservativeGcSpeedInBytesPerMillisecond = 200000;
+  if (mutator_speed == 0) return kMinMutatorUtilization;
+  if (gc_speed == 0) gc_speed = kConservativeGcSpeedInBytesPerMillisecond;
+  // Derivation:
+  // mutator_utilization = mutator_time / (mutator_time + gc_time)
+  // mutator_time = 1 / mutator_speed
+  // gc_time = 1 / gc_speed
+  // mutator_utilization = (1 / mutator_speed) /
+  //                       (1 / mutator_speed + 1 / gc_speed)
+  // mutator_utilization = gc_speed / (mutator_speed + gc_speed)
+  return gc_speed / (mutator_speed + gc_speed);
+}
+
+
+double Heap::YoungGenerationMutatorUtilization() {
+  double mutator_speed = static_cast<double>(
+      tracer()->NewSpaceAllocationThroughputInBytesPerMillisecond());
+  double gc_speed = static_cast<double>(
+      tracer()->ScavengeSpeedInBytesPerMillisecond(kForSurvivedObjects));
+  double result = ComputeMutatorUtilization(mutator_speed, gc_speed);
+  if (FLAG_trace_mutator_utilization) {
+    PrintIsolate(isolate(),
+                 "Young generation mutator utilization = %.3f ("
+                 "mutator_speed=%.f, gc_speed=%.f)\n",
+                 result, mutator_speed, gc_speed);
+  }
+  return result;
+}
+
+
+double Heap::OldGenerationMutatorUtilization() {
+  double mutator_speed = static_cast<double>(
+      tracer()->OldGenerationAllocationThroughputInBytesPerMillisecond());
+  double gc_speed = static_cast<double>(
+      tracer()->CombinedMarkCompactSpeedInBytesPerMillisecond());
+  double result = ComputeMutatorUtilization(mutator_speed, gc_speed);
+  if (FLAG_trace_mutator_utilization) {
+    PrintIsolate(isolate(),
+                 "Old generation mutator utilization = %.3f ("
+                 "mutator_speed=%.f, gc_speed=%.f)\n",
+                 result, mutator_speed, gc_speed);
+  }
+  return result;
+}
+
+
 bool Heap::HasLowYoungGenerationAllocationRate() {
   const double high_mutator_utilization = 0.993;
-  double mutator_speed = static_cast<double>(
-      tracer()->NewSpaceAllocationThroughputInBytesPerMillisecond());
-  double gc_speed = static_cast<double>(
-      tracer()->ScavengeSpeedInBytesPerMillisecond(kForSurvivedObjects));
-  if (mutator_speed == 0 || gc_speed == 0) return false;
-  double mutator_utilization = gc_speed / (mutator_speed + gc_speed);
-  return mutator_utilization > high_mutator_utilization;
+  return YoungGenerationMutatorUtilization() > high_mutator_utilization;
 }
 
 
 bool Heap::HasLowOldGenerationAllocationRate() {
   const double high_mutator_utilization = 0.993;
-  double mutator_speed = static_cast<double>(
-      tracer()->OldGenerationAllocationThroughputInBytesPerMillisecond());
-  double gc_speed = static_cast<double>(
-      tracer()->CombinedMarkCompactSpeedInBytesPerMillisecond());
-  if (mutator_speed == 0 || gc_speed == 0) return false;
-  double mutator_utilization = gc_speed / (mutator_speed + gc_speed);
-  return mutator_utilization > high_mutator_utilization;
+  return OldGenerationMutatorUtilization() > high_mutator_utilization;
 }
 
 
 bool Heap::HasLowAllocationRate() {
   return HasLowYoungGenerationAllocationRate() &&
          HasLowOldGenerationAllocationRate();
 }
 
 
 bool Heap::HasHighFragmentation() {
   intptr_t used = PromotedSpaceSizeOfObjects();
   intptr_t committed = CommittedOldGenerationMemory();
   return HasHighFragmentation(used, committed);
 }
 
 
 bool Heap::HasHighFragmentation(intptr_t used, intptr_t committed) {
   const intptr_t kSlack = 16 * MB;
   // Fragmentation is high if committed > 2 * used + kSlack.
   // Rewrite the exression to avoid overflow.
   return committed - used > used + kSlack;
 }
 
 
 void Heap::ReduceNewSpaceSize() {
-  if (!FLAG_predictable && HasLowAllocationRate()) {
+  // TODO(ulan): Unify this constant with the similar constant in
+  // GCIdleTimeHandler once the change is merged to 4.5.
+  static const size_t kLowAllocationThroughput = 1000;
+  size_t allocation_throughput =
+      tracer()->CurrentAllocationThroughputInBytesPerMillisecond();
+  if (FLAG_predictable || allocation_throughput == 0) return;
+  if (allocation_throughput < kLowAllocationThroughput) {
     new_space_.Shrink();
     UncommitFromSpace();
   }
 }
 
 
+void Heap::FinalizeIncrementalMarkingIfComplete(const char* comment) {
+  if (FLAG_overapproximate_weak_closure &&
+      (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
+       (!incremental_marking()->weak_closure_was_overapproximated() &&
+        mark_compact_collector_.marking_deque()->IsEmpty()))) {
+    OverApproximateWeakClosure(comment);
+  } else if (incremental_marking()->IsComplete() ||
+             (mark_compact_collector_.marking_deque()->IsEmpty())) {
+    CollectAllGarbage(kNoGCFlags, comment);
+  }
+}
+
+
 bool Heap::TryFinalizeIdleIncrementalMarking(
     double idle_time_in_ms, size_t size_of_objects,
     size_t final_incremental_mark_compact_speed_in_bytes_per_ms) {
   if (FLAG_overapproximate_weak_closure &&
       (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
        (!incremental_marking()->weak_closure_was_overapproximated() &&
         mark_compact_collector_.marking_deque()->IsEmpty() &&
         gc_idle_time_handler_.ShouldDoOverApproximateWeakClosure(
             static_cast<size_t>(idle_time_in_ms))))) {
     OverApproximateWeakClosure(
@@ skipping 32 matching lines @@
   heap_state.scavenge_speed_in_bytes_per_ms =
       static_cast<size_t>(tracer()->ScavengeSpeedInBytesPerMillisecond());
   heap_state.used_new_space_size = new_space_.Size();
   heap_state.new_space_capacity = new_space_.Capacity();
   heap_state.new_space_allocation_throughput_in_bytes_per_ms =
       tracer()->NewSpaceAllocationThroughputInBytesPerMillisecond();
   return heap_state;
 }
 
 
+double Heap::AdvanceIncrementalMarking(
+    intptr_t step_size_in_bytes, double deadline_in_ms,
+    IncrementalMarking::StepActions step_actions) {
+  DCHECK(!incremental_marking()->IsStopped());
+
+  if (step_size_in_bytes == 0) {
+    step_size_in_bytes = GCIdleTimeHandler::EstimateMarkingStepSize(
+        static_cast<size_t>(GCIdleTimeHandler::kIncrementalMarkingStepTimeInMs),
+        static_cast<size_t>(
+            tracer()->FinalIncrementalMarkCompactSpeedInBytesPerMillisecond()));
+  }
+
+  double remaining_time_in_ms = 0.0;
+  do {
+    incremental_marking()->Step(
+        step_size_in_bytes, step_actions.completion_action,
+        step_actions.force_marking, step_actions.force_completion);
+    remaining_time_in_ms = deadline_in_ms - MonotonicallyIncreasingTimeInMs();
+  } while (remaining_time_in_ms >=
+               2.0 * GCIdleTimeHandler::kIncrementalMarkingStepTimeInMs &&
+           !incremental_marking()->IsComplete() &&
+           !mark_compact_collector_.marking_deque()->IsEmpty());
+  return remaining_time_in_ms;
+}
+
+
 bool Heap::PerformIdleTimeAction(GCIdleTimeAction action,
                                  GCIdleTimeHandler::HeapState heap_state,
                                  double deadline_in_ms) {
   bool result = false;
   switch (action.type) {
     case DONE:
       result = true;
       break;
     case DO_INCREMENTAL_MARKING: {
-      DCHECK(!incremental_marking()->IsStopped());
-      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());
+      const double remaining_idle_time_in_ms =
+          AdvanceIncrementalMarking(action.parameter, deadline_in_ms,
+                                    IncrementalMarking::IdleStepActions());
       if (remaining_idle_time_in_ms > 0.0) {
         action.additional_work = 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: {
       DCHECK(contexts_disposed_ > 0);
       HistogramTimerScope scope(isolate_->counters()->gc_context());
@@ skipping 2004 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