Revert of [heap] Simplify distribution of remaining memory during sweeping & compaction

test/cctest/heap/test-spaces.cc

Index: test/cctest/heap/test-spaces.cc
diff --git a/test/cctest/heap/test-spaces.cc b/test/cctest/heap/test-spaces.cc
index 92224caea83410f5b062d761eb00a736cccdf24a..2698411eb5867ba6f15c96dba5ba996622957494 100644
--- a/test/cctest/heap/test-spaces.cc
+++ b/test/cctest/heap/test-spaces.cc
@@ -448,6 +448,236 @@
 }
 
 
+TEST(CompactionSpaceUsingExternalMemory) {
+  const int kObjectSize = 512;
+
+  Isolate* isolate = CcTest::i_isolate();
+  Heap* heap = isolate->heap();
+  MemoryAllocator* allocator = new MemoryAllocator(isolate);
+  CHECK(allocator != nullptr);
+  CHECK(allocator->SetUp(heap->MaxReserved(), heap->MaxExecutableSize()));
+  TestMemoryAllocatorScope test_scope(isolate, allocator);
+
+  CompactionSpaceCollection* collection = new CompactionSpaceCollection(heap);
+  CompactionSpace* compaction_space = collection->Get(OLD_SPACE);
+  CHECK(compaction_space != NULL);
+  CHECK(compaction_space->SetUp());
+
+  OldSpace* old_space = new OldSpace(heap, OLD_SPACE, NOT_EXECUTABLE);
+  CHECK(old_space != NULL);
+  CHECK(old_space->SetUp());
+
+  // The linear allocation area already counts as used bytes, making
+  // exact testing impossible.
+  heap->DisableInlineAllocation();
+
+  // Test:
+  // * Allocate a backing store in old_space.
+  // * Compute the number num_rest_objects of kObjectSize objects that fit into
+  //   of available memory.
+  //   kNumRestObjects.
+  // * Add the rest of available memory to the compaction space.
+  // * Allocate kNumRestObjects in the compaction space.
+  // * Allocate one object more.
+  // * Merge the compaction space and compare the expected number of pages.
+
+  // Allocate a single object in old_space to initialize a backing page.
+  old_space->AllocateRawUnaligned(kObjectSize).ToObjectChecked();
+  // Compute the number of objects that fit into the rest in old_space.
+  intptr_t rest = static_cast<int>(old_space->Available());
+  CHECK_GT(rest, 0);
+  intptr_t num_rest_objects = rest / kObjectSize;
+  // After allocating num_rest_objects in compaction_space we allocate a bit
+  // more.
+  const intptr_t kAdditionalCompactionMemory = kObjectSize;
+  // We expect a single old_space page.
+  const intptr_t kExpectedInitialOldSpacePages = 1;
+  // We expect a single additional page in compaction space because we mostly
+  // use external memory.
+  const intptr_t kExpectedCompactionPages = 1;
+  // We expect two pages to be reachable from old_space in the end.
+  const intptr_t kExpectedOldSpacePagesAfterMerge = 2;
+
+  CHECK_EQ(old_space->CountTotalPages(), kExpectedInitialOldSpacePages);
+  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);
+  CHECK_EQ(compaction_space->CountTotalPages(), 0);
+  CHECK_EQ(compaction_space->Capacity(), rest);
+  while (num_rest_objects-- > 0) {
+    compaction_space->AllocateRawUnaligned(kObjectSize).ToObjectChecked();
+  }
+  // We only used external memory so far.
+  CHECK_EQ(compaction_space->CountTotalPages(), 0);
+  // Additional allocation.
+  compaction_space->AllocateRawUnaligned(kAdditionalCompactionMemory)
+      .ToObjectChecked();
+  // Now the compaction space shouldve also acquired a page.
+  CHECK_EQ(compaction_space->CountTotalPages(), kExpectedCompactionPages);
+
+  old_space->MergeCompactionSpace(compaction_space);
+  CHECK_EQ(old_space->CountTotalPages(), kExpectedOldSpacePagesAfterMerge);
+
+  delete collection;
+  delete old_space;
+
+  allocator->TearDown();
+  delete allocator;
+}
+
+
+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();