Reapply the semispace growth policy change in isolation....

src/spaces.cc

 // Copyright 2006-2008 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 844 matching lines @@
 bool NewSpace::Setup(Address start, int size) {
   // Setup new space based on the preallocated memory block defined by
   // start and size. The provided space is divided into two semi-spaces.
   // To support fast containment testing in the new space, the size of
   // this chunk must be a power of two and it must be aligned to its size.
   int initial_semispace_capacity = Heap::InitialSemiSpaceSize();
   int maximum_semispace_capacity = Heap::SemiSpaceSize();
 
   ASSERT(initial_semispace_capacity <= maximum_semispace_capacity);
   ASSERT(IsPowerOf2(maximum_semispace_capacity));
-  maximum_capacity_ = maximum_semispace_capacity;
-  capacity_ = initial_semispace_capacity;
 
   // Allocate and setup the histogram arrays if necessary.
 #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
   allocated_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
   promoted_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
 
 #define SET_NAME(name) allocated_histogram_[name].set_name(#name); \
                        promoted_histogram_[name].set_name(#name);
   INSTANCE_TYPE_LIST(SET_NAME)
 #undef SET_NAME
 #endif
 
-  ASSERT(size == 2 * maximum_capacity_);
+  ASSERT(size == 2 * maximum_semispace_capacity);
   ASSERT(IsAddressAligned(start, size, 0));
 
-  if (!to_space_.Setup(start, capacity_, maximum_capacity_)) {
+  if (!to_space_.Setup(start,
+                       initial_semispace_capacity,
+                       maximum_semispace_capacity)) {
     return false;
   }
-  if (!from_space_.Setup(start + maximum_capacity_,
-                         capacity_,
-                         maximum_capacity_)) {
+  if (!from_space_.Setup(start + maximum_semispace_capacity,
+                         initial_semispace_capacity,
+                         maximum_semispace_capacity)) {
     return false;
   }
 
   start_ = start;
   address_mask_ = ~(size - 1);
   object_mask_ = address_mask_ | kHeapObjectTag;
   object_expected_ = reinterpret_cast<uintptr_t>(start) | kHeapObjectTag;
 
   allocation_info_.top = to_space_.low();
   allocation_info_.limit = to_space_.high();
@@ skipping 11 matching lines @@
     DeleteArray(allocated_histogram_);
     allocated_histogram_ = NULL;
   }
   if (promoted_histogram_) {
     DeleteArray(promoted_histogram_);
     promoted_histogram_ = NULL;
   }
 #endif
 
   start_ = NULL;
-  capacity_ = 0;
   allocation_info_.top = NULL;
   allocation_info_.limit = NULL;
   mc_forwarding_info_.top = NULL;
   mc_forwarding_info_.limit = NULL;
 
   to_space_.TearDown();
   from_space_.TearDown();
 }
 
 
@@ skipping 15 matching lines @@
 #endif
 
 
 void NewSpace::Flip() {
   SemiSpace tmp = from_space_;
   from_space_ = to_space_;
   to_space_ = tmp;
 }
 
 
-bool NewSpace::Double() {
-  ASSERT(capacity_ <= maximum_capacity_ / 2);
+bool NewSpace::Grow() {
+  ASSERT(Capacity() < MaximumCapacity());
   // TODO(1240712): Failure to double the from space can result in
   // semispaces of different sizes.  In the event of that failure, the
   // to space doubling should be rolled back before returning false.
-  if (!to_space_.Double() || !from_space_.Double()) return false;
-  capacity_ *= 2;
+  if (!to_space_.Grow() || !from_space_.Grow()) return false;
   allocation_info_.limit = to_space_.high();
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
   return true;
 }
 
 
 void NewSpace::ResetAllocationInfo() {
   allocation_info_.top = to_space_.low();
   allocation_info_.limit = to_space_.high();
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
@@ skipping 101 matching lines @@
   return Commit();
 }
 
 
 void SemiSpace::TearDown() {
   start_ = NULL;
   capacity_ = 0;
 }
 
 
-bool SemiSpace::Double() {
-  if (!MemoryAllocator::CommitBlock(high(), capacity_, executable())) {
+bool SemiSpace::Grow() {
+  // Commit 50% extra space but only up to maximum capacity.
+  int maximum_extra = maximum_capacity_ - capacity_;
+  int extra = Min(RoundUp(capacity_ / 2, OS::AllocateAlignment()),
+                  maximum_extra);
+  if (!MemoryAllocator::CommitBlock(high(), extra, executable())) {
     return false;
   }
-  capacity_ *= 2;
+  capacity_ += extra;
   return true;
 }
 
 
 #ifdef DEBUG
 void SemiSpace::Print() { }
 
 
 void SemiSpace::Verify() { }
 #endif
@@ skipping 1501 matching lines @@
                      reinterpret_cast<Object**>(object->address()
                                                 + Page::kObjectAreaSize),
                      allocation_top);
       PrintF("\n");
     }
   }
 }
 #endif  // DEBUG
 
 } }  // namespace v8::internal