Tweak the new context disposal GC heuristic to cleanly separate...

src/heap.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 97 matching lines @@
 int Heap::survived_since_last_expansion_ = 0;
 int Heap::external_allocation_limit_ = 0;
 
 Heap::HeapState Heap::gc_state_ = NOT_IN_GC;
 
 int Heap::mc_count_ = 0;
 int Heap::gc_count_ = 0;
 
 int Heap::always_allocate_scope_depth_ = 0;
 int Heap::linear_allocation_scope_depth_ = 0;
-bool Heap::context_disposed_pending_ = false;
+
+int Heap::contexts_disposed_ = 0;
+bool Heap::context_disposed_use_deprecated_heuristic_ = true;
+bool Heap::context_disposed_deprecated_pending_ = false;
 
 #ifdef DEBUG
 bool Heap::allocation_allowed_ = true;
 
 int Heap::allocation_timeout_ = 0;
 bool Heap::disallow_allocation_failure_ = false;
 #endif  // DEBUG
 
 
 int Heap::Capacity() {
@@ skipping 235 matching lines @@
 void Heap::CollectAllGarbage(bool force_compaction) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
   // cause a full GC.
   MarkCompactCollector::SetForceCompaction(force_compaction);
   CollectGarbage(0, OLD_POINTER_SPACE);
   MarkCompactCollector::SetForceCompaction(false);
 }
 
 
-void Heap::CollectAllGarbageIfContextDisposed(bool notified) {
-  // If the request has ever been the result of an explicit
-  // notification, we ignore non-notified requests. This is a
-  // temporary solution to let the two ways of achieving GC at
-  // context disposal time co-exist.
-  static bool ever_notified = false;
-  if (notified) ever_notified = true;
-  if (ever_notified && !notified) return;
-
+void Heap::CollectAllGarbageIfContextDisposedDeprecated() {
+  if (!context_disposed_use_deprecated_heuristic_) return;
   // If the garbage collector interface is exposed through the global
   // gc() function, we avoid being clever about forcing GCs when
   // contexts are disposed and leave it to the embedder to make
   // informed decisions about when to force a collection.
-  if (!FLAG_expose_gc && (notified || context_disposed_pending_)) {
+  if (!FLAG_expose_gc && context_disposed_deprecated_pending_) {
     HistogramTimerScope scope(&Counters::gc_context);
     CollectAllGarbage(false);
   }
-  context_disposed_pending_ = false;
+  context_disposed_deprecated_pending_ = false;
 }
 
 
 void Heap::NotifyContextDisposed() {
-  context_disposed_pending_ = true;
+  context_disposed_use_deprecated_heuristic_ = false;
+  contexts_disposed_++;
+}
+
+
+void Heap::NotifyContextDisposedDeprecated() {
+  if (!context_disposed_use_deprecated_heuristic_) return;
+  context_disposed_deprecated_pending_ = true;
 }
 
 
 bool Heap::CollectGarbage(int requested_size, AllocationSpace space) {
   // The VM is in the GC state until exiting this function.
   VMState state(GC);
 
 #ifdef DEBUG
   // Reset the allocation timeout to the GC interval, but make sure to
   // allow at least a few allocations after a collection. The reason
@@ skipping 225 matching lines @@
 
   MarkCompactEpilogue(is_compacting);
 
   LOG(ResourceEvent("markcompact", "end"));
 
   gc_state_ = NOT_IN_GC;
 
   Shrink();
 
   Counters::objs_since_last_full.Set(0);
-  context_disposed_pending_ = false;
+
+  contexts_disposed_ = 0;
+  context_disposed_deprecated_pending_ = false;
 }
 
 
 void Heap::MarkCompactPrologue(bool is_compacting) {
   // At any old GC clear the keyed lookup cache to enable collection of unused
   // maps.
   KeyedLookupCache::Clear();
   ContextSlotCache::Clear();
   DescriptorLookupCache::Clear();
 
@@ skipping 2428 matching lines @@
 }
 
 
 bool Heap::IdleNotification() {
   static const int kIdlesBeforeScavenge = 4;
   static const int kIdlesBeforeMarkSweep = 7;
   static const int kIdlesBeforeMarkCompact = 8;
   static int number_idle_notifications = 0;
   static int last_gc_count = gc_count_;
 
+  if (!FLAG_expose_gc && (contexts_disposed_ > 0)) {
+    HistogramTimerScope scope(&Counters::gc_context);
+    CollectAllGarbage(false);
+    ASSERT(contexts_disposed_ == 0);
+    return false;
+  }
+
   bool finished = false;
 
   if (last_gc_count == gc_count_) {
     number_idle_notifications++;
   } else {
     number_idle_notifications = 0;
     last_gc_count = gc_count_;
   }
 
   if (number_idle_notifications == kIdlesBeforeScavenge) {
@@ skipping 1137 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal