Grow heap slower if GC freed many global handles.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 4dea51050d3f1a37e21b81ae7ea9ec53ceb4d341..9c38904c924631db439f252d97d16025031b0f29 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -61,7 +61,6 @@ Heap::Heap()
 // Will be 4 * reserved_semispace_size_ to ensure that young
 // generation can be aligned to its size.
       maximum_committed_(0),
-      old_space_growing_factor_(4),
       survived_since_last_expansion_(0),
       sweep_generation_(0),
       always_allocate_scope_depth_(0),
@@ -90,7 +89,6 @@ Heap::Heap()
       allocation_timeout_(0),
 #endif  // DEBUG
       old_generation_allocation_limit_(kMinimumOldGenerationAllocationLimit),
-      size_of_old_gen_at_last_old_space_gc_(0),
       old_gen_exhausted_(false),
       inline_allocation_disabled_(false),
       store_buffer_rebuilder_(store_buffer()),
@@ -1056,7 +1054,7 @@ bool Heap::PerformGarbageCollection(
     GarbageCollector collector,
     GCTracer* tracer,
     const v8::GCCallbackFlags gc_callback_flags) {
-  bool next_gc_likely_to_collect_more = false;
+  int freed_global_handles = 0;
 
   if (collector != SCAVENGER) {
     PROFILE(isolate_, CodeMovingGCEvent());
@@ -1096,12 +1094,11 @@ bool Heap::PerformGarbageCollection(
     // Perform mark-sweep with optional compaction.
     MarkCompact(tracer);
     sweep_generation_++;
-
-    size_of_old_gen_at_last_old_space_gc_ = PromotedSpaceSizeOfObjects();
-
+    // Temporarily set the limit for case when PostGarbageCollectionProcessing
+    // allocates and triggers GC. The real limit is set at after
+    // PostGarbageCollectionProcessing.
     old_generation_allocation_limit_ =
-        OldGenerationAllocationLimit(size_of_old_gen_at_last_old_space_gc_);
-
+        OldGenerationAllocationLimit(PromotedSpaceSizeOfObjects(), 0);
     old_gen_exhausted_ = false;
   } else {
     tracer_ = tracer;
@@ -1120,7 +1117,7 @@ bool Heap::PerformGarbageCollection(
   gc_post_processing_depth_++;
   { AllowHeapAllocation allow_allocation;
     GCTracer::Scope scope(tracer, GCTracer::Scope::EXTERNAL);
-    next_gc_likely_to_collect_more =
+    freed_global_handles =
         isolate_->global_handles()->PostGarbageCollectionProcessing(
             collector, tracer);
   }
@@ -1135,6 +1132,9 @@ bool Heap::PerformGarbageCollection(
     // Register the amount of external allocated memory.
     amount_of_external_allocated_memory_at_last_global_gc_ =
         amount_of_external_allocated_memory_;
+    old_generation_allocation_limit_ =
+        OldGenerationAllocationLimit(PromotedSpaceSizeOfObjects(),
+                                     freed_global_handles);
   }
 
   { GCCallbacksScope scope(this);
@@ -1153,7 +1153,7 @@ bool Heap::PerformGarbageCollection(
   }
 #endif
 
-  return next_gc_likely_to_collect_more;
+  return freed_global_handles > 0;
 }
 
 
@@ -4959,12 +4959,6 @@ bool Heap::ConfigureHeap(int max_semi_space_size,
 
   code_range_size_ = code_range_size * MB;
 
-  // We set the old generation growing factor to 2 to grow the heap slower on
-  // memory-constrained devices.
-  if (max_old_generation_size_ <= kMaxOldSpaceSizeMediumMemoryDevice) {
-    old_space_growing_factor_ = 2;
-  }
-
   configured_ = true;
   return true;
 }
@@ -5033,6 +5027,45 @@ int64_t Heap::PromotedExternalMemorySize() {
 }
 
 
+intptr_t Heap::OldGenerationAllocationLimit(intptr_t old_gen_size,
+                                            int freed_global_handles) {
+  const int kMaxHandles = 1000;
+  const int kMinHandles = 100;
+  double min_factor = 1.1;
+  double max_factor = 4;
+  // We set the old generation growing factor to 2 to grow the heap slower on
+  // memory-constrained devices.
+  if (max_old_generation_size_ <= kMaxOldSpaceSizeMediumMemoryDevice) {
+    max_factor = 2;
+  }
+  // If there are many freed global handles, then the next full GC will
+  // likely collect a lot of garbage. Choose the heap growing factor
+  // depending on freed global handles.
+  // TODO(ulan, hpayer): Take into account mutator utilization.
+  double factor;
+  if (freed_global_handles <= kMinHandles) {
+    factor = max_factor;
+  } else if (freed_global_handles >= kMaxHandles) {
+    factor = min_factor;
+  } else {
+    factor = max_factor -

[Hannes Payer (out of office), 2014/06/25 09:24:00]

Could you please leave a comment here that explains what that function does?

+             (freed_global_handles - kMinHandles) * (max_factor - min_factor) /
+             (kMaxHandles - kMinHandles);
+  }
+
+  if (FLAG_stress_compaction ||
+      mark_compact_collector()->reduce_memory_footprint_) {
+    factor = min_factor;
+  }
+
+  intptr_t limit = static_cast<intptr_t>(old_gen_size * factor);
+  limit = Max(limit, kMinimumOldGenerationAllocationLimit);
+  limit += new_space_.Capacity();
+  intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
+  return Min(limit, halfway_to_the_max);
+}
+
+
 void Heap::EnableInlineAllocation() {
   if (!inline_allocation_disabled_) return;
   inline_allocation_disabled_ = false;