Revert of "[heap] Divide available memory upon compaction tasks" (patchset #5...

Revert of "[heap] Divide available memory upon compaction tasks" (patchset #5 id:90008 of https://codereview.chromium.org/1415733004/ )

Reason for revert:
Failing again: http://build.chromium.org/p/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/2183

Original issue's description:
> Reland of "[heap] Divide available memory upon compaction tasks"
>
> This reverts commit cf71c28f.
>
> Original message:
>
> [heap] Divide available memory upon compaction tasks
> - Fairly (round-robin) divide available memory upon compaction tasks.
> - Ensure an upper limit (of memory) since dividing is O(n) for n free-space
>   nodes.
> - Refill from free lists managed by sweeper once a compaction space becomes
>   empty.
>
> Assumption for dividing memory: Memory in the free lists is sparse upon starting
> compaction (which means that only few nodes are available), except for memory
> reducer GCs, which happen in idle time though (so it's less of a problem).
>
> BUG=chromium:524425
> LOG=N
>
> Committed: https://crrev.com/63f42ecb965d04877f45043c1416170b6f79b962
> Cr-Commit-Position: refs/heads/master@{#31436}

TBR=hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:524425

Review URL: https://codereview.chromium.org/1405273003

Cr-Commit-Position: refs/heads/master@{#31439}

src/heap/heap.cc

@@ -3047,7 +3047,6 @@ void Heap::CreateFillerObjectAt(Address addr, int size) {
     filler->set_map_no_write_barrier(
         reinterpret_cast<Map*>(root(kTwoPointerFillerMapRootIndex)));
   } else {
-    DCHECK_GT(size, 2 * kPointerSize);
     filler->set_map_no_write_barrier(
         reinterpret_cast<Map*>(root(kFreeSpaceMapRootIndex)));
     FreeSpace::cast(filler)->nobarrier_set_size(size);

src/heap/mark-compact.cc

@@ -566,9 +566,9 @@ void MarkCompactCollector::EnsureSweepingCompleted() {
 
   ParallelSweepSpacesComplete();
   sweeping_in_progress_ = false;
-  heap()->old_space()->RefillFreeList();
-  heap()->code_space()->RefillFreeList();
-  heap()->map_space()->RefillFreeList();
+  RefillFreeList(heap()->paged_space(OLD_SPACE));
+  RefillFreeList(heap()->paged_space(CODE_SPACE));
+  RefillFreeList(heap()->paged_space(MAP_SPACE));
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap && !evacuation()) {
@@ -588,6 +588,26 @@ bool MarkCompactCollector::IsSweepingCompleted() {
 }
 
 
+void MarkCompactCollector::RefillFreeList(PagedSpace* space) {
+  FreeList* free_list;
+
+  if (space == heap()->old_space()) {
+    free_list = free_list_old_space_.get();
+  } else if (space == heap()->code_space()) {
+    free_list = free_list_code_space_.get();
+  } else if (space == heap()->map_space()) {
+    free_list = free_list_map_space_.get();
+  } else {
+    // Any PagedSpace might invoke RefillFreeLists, so we need to make sure
+    // to only refill them for the old space.
+    return;
+  }
+
+  intptr_t added = space->free_list()->Concatenate(free_list);
+  space->accounting_stats_.IncreaseCapacity(added);
+}
+
+
 void Marking::TransferMark(Heap* heap, Address old_start, Address new_start) {
   // This is only used when resizing an object.
   DCHECK(MemoryChunk::FromAddress(old_start) ==
@@ -3415,10 +3435,11 @@ void MarkCompactCollector::EvacuatePagesInParallel() {
     compaction_spaces_for_tasks[i] = new CompactionSpaceCollection(heap());
   }
 
-  heap()->old_space()->DivideUponCompactionSpaces(compaction_spaces_for_tasks,
-                                                  num_tasks);
-  heap()->code_space()->DivideUponCompactionSpaces(compaction_spaces_for_tasks,
-                                                   num_tasks);
+  compaction_spaces_for_tasks[0]->Get(OLD_SPACE)->MoveOverFreeMemory(
+      heap()->old_space());
+  compaction_spaces_for_tasks[0]
+      ->Get(CODE_SPACE)
+      ->MoveOverFreeMemory(heap()->code_space());
 
   compaction_in_progress_ = true;
   // Kick off parallel tasks.
@@ -3430,7 +3451,9 @@ void MarkCompactCollector::EvacuatePagesInParallel() {
   }
 
   // Contribute in main thread. Counter and signal are in principal not needed.
+  concurrent_compaction_tasks_active_++;
   EvacuatePages(compaction_spaces_for_tasks[0], &migration_slots_buffer_);
+  pending_compaction_tasks_semaphore_.Signal();
 
   WaitUntilCompactionCompleted();
 

src/heap/mark-compact.h

@@ -466,6 +466,8 @@ class MarkCompactCollector {
   // return true if the sweeper threads are done processing the pages.
   bool IsSweepingCompleted();
 
+  void RefillFreeList(PagedSpace* space);
+
   // Checks if sweeping is in progress right now on any space.
   bool sweeping_in_progress() { return sweeping_in_progress_; }
 
@@ -510,20 +512,6 @@ class MarkCompactCollector {
   // address range.
   void RemoveObjectSlots(Address start_slot, Address end_slot);
 
-  //
-  // Free lists filled by sweeper and consumed by corresponding spaces
-  // (including compaction spaces).
-  //
-  base::SmartPointer<FreeList>& free_list_old_space() {
-    return free_list_old_space_;
-  }
-  base::SmartPointer<FreeList>& free_list_code_space() {
-    return free_list_code_space_;
-  }
-  base::SmartPointer<FreeList>& free_list_map_space() {
-    return free_list_map_space_;
-  }
-
  private:
   class CompactionTask;
   class SweeperTask;

src/heap/spaces.cc

@@ -982,101 +982,6 @@ void PagedSpace::TearDown() {
 }
 
 
-void PagedSpace::AddMemory(Address start, intptr_t size) {
-  accounting_stats_.ExpandSpace(static_cast<int>(size));
-  Free(start, static_cast<int>(size));
-}
-
-
-FreeSpace* PagedSpace::TryRemoveMemory(intptr_t size_in_bytes) {
-  FreeSpace* free_space = free_list()->TryRemoveMemory(size_in_bytes);
-  if (free_space != nullptr) {
-    accounting_stats_.DecreaseCapacity(free_space->size());
-  }
-  return free_space;
-}
-
-
-void PagedSpace::DivideUponCompactionSpaces(CompactionSpaceCollection** other,
-                                            int num, intptr_t limit) {
-  DCHECK_GT(num, 0);
-  DCHECK(other != nullptr);
-
-  if (limit == 0) limit = std::numeric_limits<intptr_t>::max();
-
-  EmptyAllocationInfo();
-
-  bool memory_available = true;
-  bool spaces_need_memory = true;
-  FreeSpace* node = nullptr;
-  CompactionSpace* current_space = nullptr;
-  // Iterate over spaces and memory as long as we have memory and there are
-  // spaces in need of some.
-  while (memory_available && spaces_need_memory) {
-    spaces_need_memory = false;
-    // Round-robin over all spaces.
-    for (int i = 0; i < num; i++) {
-      current_space = other[i]->Get(identity());
-      if (current_space->free_list()->Available() < limit) {
-        // Space has not reached its limit. Try to get some memory.
-        spaces_need_memory = true;
-        node = TryRemoveMemory(limit - current_space->free_list()->Available());
-        if (node != nullptr) {
-          CHECK(current_space->identity() == identity());
-          current_space->AddMemory(node->address(), node->size());
-        } else {
-          memory_available = false;
-          break;
-        }
-      }
-    }
-  }
-}
-
-
-void PagedSpace::RefillFreeList() {
-  MarkCompactCollector* collector = heap()->mark_compact_collector();
-  FreeList* free_list = nullptr;
-  if (this == heap()->old_space()) {
-    free_list = collector->free_list_old_space().get();
-  } else if (this == heap()->code_space()) {
-    free_list = collector->free_list_code_space().get();
-  } else if (this == heap()->map_space()) {
-    free_list = collector->free_list_map_space().get();
-  } else {
-    // Any PagedSpace might invoke RefillFreeList. We filter all but our old
-    // generation spaces out.
-    return;
-  }
-  DCHECK(free_list != nullptr);
-  intptr_t added = free_list_.Concatenate(free_list);
-  accounting_stats_.IncreaseCapacity(added);
-}
-
-
-void CompactionSpace::RefillFreeList() {
-  MarkCompactCollector* collector = heap()->mark_compact_collector();
-  FreeList* free_list = nullptr;
-  if (identity() == OLD_SPACE) {
-    free_list = collector->free_list_old_space().get();
-  } else if (identity() == CODE_SPACE) {
-    free_list = collector->free_list_code_space().get();
-  } else {
-    // Compaction spaces only represent old or code space.
-    UNREACHABLE();
-  }
-  DCHECK(free_list != nullptr);
-  intptr_t refilled = 0;
-  while (refilled < kCompactionMemoryWanted) {
-    FreeSpace* node =
-        free_list->TryRemoveMemory(kCompactionMemoryWanted - refilled);
-    if (node == nullptr) return;
-    refilled += node->size();
-    AddMemory(node->address(), node->size());
-  }
-}
-
-
 void PagedSpace::MoveOverFreeMemory(PagedSpace* other) {
   DCHECK(identity() == other->identity());
   // Destroy the linear allocation space of {other}. This is needed to
@@ -1089,7 +994,8 @@ void PagedSpace::MoveOverFreeMemory(PagedSpace* other) {
   intptr_t added = free_list_.Concatenate(other->free_list());
 
   // Moved memory is not recorded as allocated memory, but rather increases and
-  // decreases capacity of the corresponding spaces.
+  // decreases capacity of the corresponding spaces. Used size and waste size
+  // are maintained by the receiving space upon allocating and freeing blocks.
   other->accounting_stats_.DecreaseCapacity(added);
   accounting_stats_.IncreaseCapacity(added);
 }
@@ -1098,19 +1004,16 @@ void PagedSpace::MoveOverFreeMemory(PagedSpace* other) {
 void PagedSpace::MergeCompactionSpace(CompactionSpace* other) {
   // Unmerged fields:
   //   area_size_
+  //   allocation_info_
+  //   end_of_unswept_pages_
+  //   unswept_free_bytes_
   //   anchor_
 
   MoveOverFreeMemory(other);
 
   // Update and clear accounting statistics.
   accounting_stats_.Merge(other->accounting_stats_);
-  other->accounting_stats_.Clear();
-
-  // The linear allocation area of {other} should be destroyed now.
-  DCHECK(other->top() == nullptr);
-  DCHECK(other->limit() == nullptr);
-
-  DCHECK(other->end_of_unswept_pages_ == nullptr);
+  other->accounting_stats_.Reset();
 
   AccountCommitted(other->CommittedMemory());
 
@@ -2477,37 +2380,6 @@ FreeSpace* FreeList::FindNodeFor(int size_in_bytes, int* node_size) {
 }
 
 
-FreeSpace* FreeList::TryRemoveMemory(intptr_t hint_size_in_bytes) {
-  hint_size_in_bytes = RoundDown(hint_size_in_bytes, kPointerSize);
-  base::LockGuard<base::Mutex> guard(&mutex_);
-  FreeSpace* node = nullptr;
-  int node_size = 0;
-  // Try to find a node that fits exactly.
-  node = FindNodeFor(static_cast<int>(hint_size_in_bytes), &node_size);
-  // If no node could be found get as much memory as possible.
-  if (node == nullptr) node = FindNodeIn(kHuge, &node_size);
-  if (node == nullptr) node = FindNodeIn(kLarge, &node_size);
-  if (node != nullptr) {
-    // We round up the size to (kSmallListMin + 1) to (a) have a size larger
-    // then the minimum size required for FreeSpace, and (b) to get a block
-    // that can actually be freed into some FreeList later on.
-    if (hint_size_in_bytes <= kSmallListMin) {
-      hint_size_in_bytes = kSmallListMin + 1;
-    }
-    // Give back left overs that were not required by {size_in_bytes}.
-    intptr_t left_over = node_size - hint_size_in_bytes;
-
-    // Do not bother to return anything below {kSmallListMin} as it would be
-    // immediately discarded anyways.
-    if (left_over > kSmallListMin) {
-      Free(node->address() + hint_size_in_bytes, static_cast<int>(left_over));
-      node->set_size(static_cast<int>(hint_size_in_bytes));
-    }
-  }
-  return node;
-}
-
-
 // Allocation on the old space free list.  If it succeeds then a new linear
 // allocation space has been set up with the top and limit of the space.  If
 // the allocation fails then NULL is returned, and the caller can perform a GC
@@ -2736,7 +2608,7 @@ HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
   if (collector->sweeping_in_progress()) {
     // First try to refill the free-list, concurrent sweeper threads
     // may have freed some objects in the meantime.
-    RefillFreeList();
+    collector->RefillFreeList(this);
 
     // Retry the free list allocation.
     HeapObject* object = free_list_.Allocate(size_in_bytes);
@@ -2744,7 +2616,7 @@ HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
 
     // If sweeping is still in progress try to sweep pages on the main thread.
     int free_chunk = collector->SweepInParallel(this, size_in_bytes);
-    RefillFreeList();
+    collector->RefillFreeList(this);
     if (free_chunk >= size_in_bytes) {
       HeapObject* object = free_list_.Allocate(size_in_bytes);
       // We should be able to allocate an object here since we just freed that

src/heap/spaces.h

@@ -19,7 +19,6 @@
 namespace v8 {
 namespace internal {
 
-class CompactionSpaceCollection;
 class Isolate;
 
 // -----------------------------------------------------------------------------
@@ -1749,14 +1748,6 @@ class FreeList {
            large_list_.available() + huge_list_.available();
   }
 
-  // The method tries to find a {FreeSpace} node of at least {size_in_bytes}
-  // size in the free list category exactly matching the size. If no suitable
-  // node could be found, the method falls back to retrieving a {FreeSpace}
-  // from the large or huge free list category.
-  //
-  // Can be used concurrently.
-  MUST_USE_RESULT FreeSpace* TryRemoveMemory(intptr_t hint_size_in_bytes);
-
   bool IsEmpty() {
     return small_list_.IsEmpty() && medium_list_.IsEmpty() &&
            large_list_.IsEmpty() && huge_list_.IsEmpty();
@@ -1868,8 +1859,6 @@ STATIC_ASSERT(sizeof(AllocationResult) == kPointerSize);
 
 class PagedSpace : public Space {
  public:
-  static const intptr_t kCompactionMemoryWanted = 500 * KB;
-
   // Creates a space with an id.
   PagedSpace(Heap* heap, AllocationSpace id, Executability executable);
 
@@ -2071,26 +2060,15 @@ class PagedSpace : public Space {
   // Return size of allocatable area on a page in this space.
   inline int AreaSize() { return area_size_; }
 
-  virtual bool is_local() { return false; }
-
   // Merges {other} into the current space. Note that this modifies {other},
   // e.g., removes its bump pointer area and resets statistics.
   void MergeCompactionSpace(CompactionSpace* other);
 
-  void DivideUponCompactionSpaces(CompactionSpaceCollection** other, int num,
-                                  intptr_t limit = kCompactionMemoryWanted);
+  void MoveOverFreeMemory(PagedSpace* other);
 
-  // Refills the free list from the corresponding free list filled by the
-  // sweeper.
-  virtual void RefillFreeList();
+  virtual bool is_local() { return false; }
 
  protected:
-  void AddMemory(Address start, intptr_t size);
-
-  FreeSpace* TryRemoveMemory(intptr_t size_in_bytes);
-
-  void MoveOverFreeMemory(PagedSpace* other);
-
   // PagedSpaces that should be included in snapshots have different, i.e.,
   // smaller, initial pages.
   virtual bool snapshotable() { return true; }
@@ -2151,9 +2129,6 @@ class PagedSpace : public Space {
 
   friend class MarkCompactCollector;
   friend class PageIterator;
-
-  // Used in cctest.
-  friend class HeapTester;
 };
 
 
@@ -2831,13 +2806,11 @@ class CompactionSpace : public PagedSpace {
     Free(start, size_in_bytes);
   }
 
-  virtual bool is_local() override { return true; }
-
-  virtual void RefillFreeList() override;
+  virtual bool is_local() { return true; }
 
  protected:
   // The space is temporary and not included in any snapshots.
-  virtual bool snapshotable() override { return false; }
+  virtual bool snapshotable() { return false; }
 };
 
 

test/cctest/heap-tester.h

@@ -10,19 +10,17 @@
 
 // Tests that should have access to private methods of {v8::internal::Heap}.
 // Those tests need to be defined using HEAP_TEST(Name) { ... }.
-#define HEAP_TEST_METHODS(V)            \
-  V(CompactionSpaceDivideMultiplePages) \
-  V(CompactionSpaceDivideSinglePage)    \
-  V(GCFlags)                            \
-  V(MarkCompactCollector)               \
-  V(NoPromotion)                        \
-  V(NumberStringCacheSize)              \
-  V(ObjectGroups)                       \
-  V(Promotion)                          \
-  V(Regression39128)                    \
-  V(ResetWeakHandle)                    \
-  V(StressHandles)                      \
-  V(TestSizeOfObjects)                  \
+#define HEAP_TEST_METHODS(V) \
+  V(GCFlags)                 \
+  V(MarkCompactCollector)    \
+  V(NoPromotion)             \
+  V(NumberStringCacheSize)   \
+  V(ObjectGroups)            \
+  V(Promotion)               \
+  V(Regression39128)         \
+  V(ResetWeakHandle)         \
+  V(StressHandles)           \
+  V(TestSizeOfObjects)       \
   V(WriteBarriersInCopyJSObject)
 
 
@@ -54,25 +52,6 @@ class HeapTester {
 
   /* test-api.cc */
   static void ResetWeakHandle(bool global_gc);
-
-  /* test-spaces.cc */
-  static CompactionSpaceCollection** InitializeCompactionSpaces(Heap* heap,
-                                                                int num_spaces);
-  static void DestroyCompactionSpaces(CompactionSpaceCollection** spaces,
-                                      int num_spaces);
-  static void MergeCompactionSpaces(PagedSpace* space,
-                                    CompactionSpaceCollection** spaces,
-                                    int num_spaces);
-  static void AllocateInCompactionSpaces(CompactionSpaceCollection** spaces,
-                                         AllocationSpace id, int num_spaces,
-                                         int num_objects, int object_size);
-  static void CompactionStats(CompactionSpaceCollection** spaces,
-                              AllocationSpace id, int num_spaces,
-                              intptr_t* capacity, intptr_t* size);
-  static void TestCompactionSpaceDivide(int num_additional_objects,
-                                        int object_size,
-                                        int num_compaction_spaces,
-                                        int additional_capacity_in_bytes);
 };
 
 }  // namespace internal

test/cctest/test-spaces.cc

@@ -34,7 +34,7 @@
 #include "src/snapshot/snapshot.h"
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
-#include "test/cctest/heap-tester.h"
+
 
 using namespace v8::internal;
 
@@ -462,8 +462,8 @@ TEST(CompactionSpaceUsingExternalMemory) {
   CHECK(allocator->SetUp(heap->MaxReserved(), heap->MaxExecutableSize()));
   TestMemoryAllocatorScope test_scope(isolate, allocator);
 
-  CompactionSpaceCollection* collection = new CompactionSpaceCollection(heap);
-  CompactionSpace* compaction_space = collection->Get(OLD_SPACE);
+  CompactionSpace* compaction_space =
+      new CompactionSpace(heap, OLD_SPACE, NOT_EXECUTABLE);
   CHECK(compaction_space != NULL);
   CHECK(compaction_space->SetUp());
 
@@ -502,11 +502,17 @@ TEST(CompactionSpaceUsingExternalMemory) {
   // We expect two pages to be reachable from old_space in the end.
   const intptr_t kExpectedOldSpacePagesAfterMerge = 2;
 
+  Object* chunk =
+      old_space->AllocateRawUnaligned(static_cast<int>(rest)).ToObjectChecked();
   CHECK_EQ(old_space->CountTotalPages(), kExpectedInitialOldSpacePages);
+  CHECK(chunk != nullptr);
+  CHECK(chunk->IsHeapObject());
+
   CHECK_EQ(compaction_space->CountTotalPages(), 0);
   CHECK_EQ(compaction_space->Capacity(), 0);
   // Make the rest of memory available for compaction.
-  old_space->DivideUponCompactionSpaces(&collection, 1, rest);
+  compaction_space->AddExternalMemory(HeapObject::cast(chunk)->address(),
+                                      static_cast<int>(rest));
   CHECK_EQ(compaction_space->CountTotalPages(), 0);
   CHECK_EQ(compaction_space->Capacity(), rest);
   while (num_rest_objects-- > 0) {
@@ -523,7 +529,7 @@ TEST(CompactionSpaceUsingExternalMemory) {
   old_space->MergeCompactionSpace(compaction_space);
   CHECK_EQ(old_space->CountTotalPages(), kExpectedOldSpacePagesAfterMerge);
 
-  delete collection;
+  delete compaction_space;
   delete old_space;
 
   allocator->TearDown();
@@ -531,157 +537,6 @@ TEST(CompactionSpaceUsingExternalMemory) {
 }
 
 
-CompactionSpaceCollection** HeapTester::InitializeCompactionSpaces(
-    Heap* heap, int num_spaces) {
-  CompactionSpaceCollection** spaces =
-      new CompactionSpaceCollection*[num_spaces];
-  for (int i = 0; i < num_spaces; i++) {
-    spaces[i] = new CompactionSpaceCollection(heap);
-  }
-  return spaces;
-}
-
-
-void HeapTester::DestroyCompactionSpaces(CompactionSpaceCollection** spaces,
-                                         int num_spaces) {
-  for (int i = 0; i < num_spaces; i++) {
-    delete spaces[i];
-  }
-  delete[] spaces;
-}
-
-
-void HeapTester::MergeCompactionSpaces(PagedSpace* space,
-                                       CompactionSpaceCollection** spaces,
-                                       int num_spaces) {
-  AllocationSpace id = space->identity();
-  for (int i = 0; i < num_spaces; i++) {
-    space->MergeCompactionSpace(spaces[i]->Get(id));
-    CHECK_EQ(spaces[i]->Get(id)->accounting_stats_.Size(), 0);
-    CHECK_EQ(spaces[i]->Get(id)->accounting_stats_.Capacity(), 0);
-    CHECK_EQ(spaces[i]->Get(id)->Waste(), 0);
-  }
-}
-
-
-void HeapTester::AllocateInCompactionSpaces(CompactionSpaceCollection** spaces,
-                                            AllocationSpace id, int num_spaces,
-                                            int num_objects, int object_size) {
-  for (int i = 0; i < num_spaces; i++) {
-    for (int j = 0; j < num_objects; j++) {
-      spaces[i]->Get(id)->AllocateRawUnaligned(object_size).ToObjectChecked();
-    }
-    spaces[i]->Get(id)->EmptyAllocationInfo();
-    CHECK_EQ(spaces[i]->Get(id)->accounting_stats_.Size(),
-             num_objects * object_size);
-    CHECK_GE(spaces[i]->Get(id)->accounting_stats_.Capacity(),
-             spaces[i]->Get(id)->accounting_stats_.Size());
-  }
-}
-
-
-void HeapTester::CompactionStats(CompactionSpaceCollection** spaces,
-                                 AllocationSpace id, int num_spaces,
-                                 intptr_t* capacity, intptr_t* size) {
-  *capacity = 0;
-  *size = 0;
-  for (int i = 0; i < num_spaces; i++) {
-    *capacity += spaces[i]->Get(id)->accounting_stats_.Capacity();
-    *size += spaces[i]->Get(id)->accounting_stats_.Size();
-  }
-}
-
-
-void HeapTester::TestCompactionSpaceDivide(int num_additional_objects,
-                                           int object_size,
-                                           int num_compaction_spaces,
-                                           int additional_capacity_in_bytes) {
-  Isolate* isolate = CcTest::i_isolate();
-  Heap* heap = isolate->heap();
-  OldSpace* old_space = new OldSpace(heap, OLD_SPACE, NOT_EXECUTABLE);
-  CHECK(old_space != nullptr);
-  CHECK(old_space->SetUp());
-  old_space->AllocateRawUnaligned(object_size).ToObjectChecked();
-  old_space->EmptyAllocationInfo();
-
-  intptr_t rest_capacity = old_space->accounting_stats_.Capacity() -
-                           old_space->accounting_stats_.Size();
-  intptr_t capacity_for_compaction_space =
-      rest_capacity / num_compaction_spaces;
-  int num_objects_in_compaction_space =
-      static_cast<int>(capacity_for_compaction_space) / object_size +
-      num_additional_objects;
-  CHECK_GT(num_objects_in_compaction_space, 0);
-  intptr_t initial_old_space_capacity = old_space->accounting_stats_.Capacity();
-
-  CompactionSpaceCollection** spaces =
-      InitializeCompactionSpaces(heap, num_compaction_spaces);
-  old_space->DivideUponCompactionSpaces(spaces, num_compaction_spaces,
-                                        capacity_for_compaction_space);
-
-  intptr_t compaction_capacity = 0;
-  intptr_t compaction_size = 0;
-  CompactionStats(spaces, OLD_SPACE, num_compaction_spaces,
-                  &compaction_capacity, &compaction_size);
-
-  intptr_t old_space_capacity = old_space->accounting_stats_.Capacity();
-  intptr_t old_space_size = old_space->accounting_stats_.Size();
-  // Compaction space memory is subtracted from the original space's capacity.
-  CHECK_EQ(old_space_capacity,
-           initial_old_space_capacity - compaction_capacity);
-  CHECK_EQ(compaction_size, 0);
-
-  AllocateInCompactionSpaces(spaces, OLD_SPACE, num_compaction_spaces,
-                             num_objects_in_compaction_space, object_size);
-
-  // Old space size and capacity should be the same as after dividing.
-  CHECK_EQ(old_space->accounting_stats_.Size(), old_space_size);
-  CHECK_EQ(old_space->accounting_stats_.Capacity(), old_space_capacity);
-
-  CompactionStats(spaces, OLD_SPACE, num_compaction_spaces,
-                  &compaction_capacity, &compaction_size);
-  MergeCompactionSpaces(old_space, spaces, num_compaction_spaces);
-
-  CHECK_EQ(old_space->accounting_stats_.Capacity(),
-           old_space_capacity + compaction_capacity);
-  CHECK_EQ(old_space->accounting_stats_.Size(),
-           old_space_size + compaction_size);
-  // We check against the expected end capacity.
-  CHECK_EQ(old_space->accounting_stats_.Capacity(),
-           initial_old_space_capacity + additional_capacity_in_bytes);
-
-  DestroyCompactionSpaces(spaces, num_compaction_spaces);
-  delete old_space;
-}
-
-
-HEAP_TEST(CompactionSpaceDivideSinglePage) {
-  const int kObjectSize = KB;
-  const int kCompactionSpaces = 4;
-  // Since the bound for objects is tight and the dividing is best effort, we
-  // subtract some objects to make sure we still fit in the initial page.
-  // A CHECK makes sure that the overall number of allocated objects stays
-  // > 0.
-  const int kAdditionalObjects = -10;
-  const int kAdditionalCapacityRequired = 0;
-  TestCompactionSpaceDivide(kAdditionalObjects, kObjectSize, kCompactionSpaces,
-                            kAdditionalCapacityRequired);
-}
-
-
-HEAP_TEST(CompactionSpaceDivideMultiplePages) {
-  const int kObjectSize = KB;
-  const int kCompactionSpaces = 4;
-  // Allocate half a page of objects to ensure that we need one more page per
-  // compaction space.
-  const int kAdditionalObjects = (Page::kPageSize / kObjectSize / 2);
-  const int kAdditionalCapacityRequired =
-      Page::kAllocatableMemory * kCompactionSpaces;
-  TestCompactionSpaceDivide(kAdditionalObjects, kObjectSize, kCompactionSpaces,
-                            kAdditionalCapacityRequired);
-}
-
-
 TEST(LargeObjectSpace) {
   v8::V8::Initialize();