[heap] Adds a young generation large object space

This CL adds the young generation lage object spaces and a flag
--young-generation-large-objects that by default allocates all
large objects in this space. This is a preparation CL. The space
is not fully functional.

Bug: chromium:852420
Change-Id: Ib66d26fa52cda89bf04787084826aeb84b6ec1ac
Reviewed-on: https://chromium-review.googlesource.com/1099164
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54056}

src/flag-definitions.h

@@ -785,6 +785,10 @@ DEFINE_BOOL(optimize_ephemerons, true,
 DEFINE_NEG_NEG_IMPLICATION(optimize_ephemerons, parallel_ephemeron_marking)
 DEFINE_NEG_NEG_IMPLICATION(optimize_ephemerons, parallel_ephemeron_visiting)
 
+DEFINE_BOOL(young_generation_large_objects, false,
+            "allocates large objects by default in the young generation large "
+            "object space")
+
 // assembler-ia32.cc / assembler-arm.cc / assembler-x64.cc
 DEFINE_BOOL(debug_code, DEBUG_BOOL,
             "generate extra code (assertions) for debugging")

src/globals.h

@@ -536,6 +536,7 @@ class MapSpace;
 class MarkCompactCollector;
 class MaybeObject;
 class NewSpace;
+class NewLargeObjectSpace;
 class Object;
 class OldSpace;
 class ParameterCount;
@@ -570,14 +571,16 @@ typedef bool (*WeakSlotCallbackWithHeap)(Heap* heap, Object** pointer);
 enum AllocationSpace {
   // TODO(v8:7464): Actually map this space's memory as read-only.
   RO_SPACE,    // Immortal, immovable and immutable objects,
-  NEW_SPACE,   // Semispaces collected with copying collector.
-  OLD_SPACE,   // May contain pointers to new space.
-  CODE_SPACE,  // No pointers to new space, marked executable.
-  MAP_SPACE,   // Only and all map objects.
-  LO_SPACE,    // Promoted large objects.
+  NEW_SPACE,   // Young generation semispaces for regular objects collected with
+               // Scavenger.
+  OLD_SPACE,   // Old generation regular object space.
+  CODE_SPACE,  // Old generation code object space, marked executable.
+  MAP_SPACE,   // Old generation map object space, non-movable.
+  LO_SPACE,    // Old generation large object space.
+  NEW_LO_SPACE,  // Young generation large object space.
 
   FIRST_SPACE = RO_SPACE,
-  LAST_SPACE = LO_SPACE,
+  LAST_SPACE = NEW_LO_SPACE,
   FIRST_GROWABLE_PAGED_SPACE = OLD_SPACE,
   LAST_GROWABLE_PAGED_SPACE = MAP_SPACE
 };

src/heap/heap-inl.h

@@ -183,7 +183,11 @@ AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationSpace space,
     }
   } else if (LO_SPACE == space) {
     DCHECK(large_object);
+    if (FLAG_young_generation_large_objects) {
+      allocation = new_lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
+    } else {
       allocation = lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
+    }
   } else if (MAP_SPACE == space) {
     allocation = map_space_->AllocateRawUnaligned(size_in_bytes);
   } else if (RO_SPACE == space) {

src/heap/heap.cc

@@ -165,6 +165,7 @@ Heap::Heap()
       code_space_(nullptr),
       map_space_(nullptr),
       lo_space_(nullptr),
+      new_lo_space_(nullptr),
       read_only_space_(nullptr),
       write_protect_code_memory_(false),
       code_space_memory_modification_scope_depth_(0),
@@ -673,6 +674,8 @@ const char* Heap::GetSpaceName(int idx) {
       return "code_space";
     case LO_SPACE:
       return "large_object_space";
+    case NEW_LO_SPACE:
+      return "new_large_object_space";
     case RO_SPACE:
       return "read_only_space";
     default:
@@ -3647,6 +3650,8 @@ bool Heap::InSpace(HeapObject* value, AllocationSpace space) {
       return map_space_->Contains(value);
     case LO_SPACE:
       return lo_space_->Contains(value);
+    case NEW_LO_SPACE:
+      return new_lo_space_->Contains(value);
     case RO_SPACE:
       return read_only_space_->Contains(value);
   }
@@ -3670,13 +3675,14 @@ bool Heap::InSpaceSlow(Address addr, AllocationSpace space) {
       return map_space_->ContainsSlow(addr);
     case LO_SPACE:
       return lo_space_->ContainsSlow(addr);
+    case NEW_LO_SPACE:
+      return new_lo_space_->ContainsSlow(addr);
     case RO_SPACE:
       return read_only_space_->ContainsSlow(addr);
   }
   UNREACHABLE();
 }
 
-
 bool Heap::IsValidAllocationSpace(AllocationSpace space) {
   switch (space) {
     case NEW_SPACE:
@@ -3684,6 +3690,7 @@ bool Heap::IsValidAllocationSpace(AllocationSpace space) {
     case CODE_SPACE:
     case MAP_SPACE:
     case LO_SPACE:
+    case NEW_LO_SPACE:
     case RO_SPACE:
       return true;
     default:
@@ -4593,6 +4600,7 @@ void Heap::SetUp() {
   space_[CODE_SPACE] = code_space_ = new CodeSpace(this);
   space_[MAP_SPACE] = map_space_ = new MapSpace(this);
   space_[LO_SPACE] = lo_space_ = new LargeObjectSpace(this);
+  space_[NEW_LO_SPACE] = new_lo_space_ = new NewLargeObjectSpace(this);
 
   // Set up the seed that is used to randomize the string hash function.
   DCHECK_EQ(Smi::kZero, hash_seed());
@@ -5529,6 +5537,8 @@ const char* AllocationSpaceName(AllocationSpace space) {
       return "MAP_SPACE";
     case LO_SPACE:
       return "LO_SPACE";
+    case NEW_LO_SPACE:
+      return "NEW_LO_SPACE";
     case RO_SPACE:
       return "RO_SPACE";
     default:
@@ -5602,6 +5612,7 @@ bool Heap::AllowedToBeMigrated(HeapObject* obj, AllocationSpace dst) {
       return dst == CODE_SPACE && type == CODE_TYPE;
     case MAP_SPACE:
     case LO_SPACE:
+    case NEW_LO_SPACE:
     case RO_SPACE:
       return false;
   }

src/heap/heap.h

@@ -1012,6 +1012,7 @@ class Heap {
   CodeSpace* code_space() { return code_space_; }
   MapSpace* map_space() { return map_space_; }
   LargeObjectSpace* lo_space() { return lo_space_; }
+  NewLargeObjectSpace* new_lo_space() { return new_lo_space_; }
   ReadOnlySpace* read_only_space() { return read_only_space_; }
 
   inline PagedSpace* paged_space(int idx);
@@ -2290,6 +2291,7 @@ class Heap {
   CodeSpace* code_space_;
   MapSpace* map_space_;
   LargeObjectSpace* lo_space_;
+  NewLargeObjectSpace* new_lo_space_;
   ReadOnlySpace* read_only_space_;
   // Map from the space id to the space.
   Space* space_[LAST_SPACE + 1];

src/heap/spaces.cc

@@ -3250,7 +3250,10 @@ HeapObject* LargeObjectIterator::Next() {
 // LargeObjectSpace
 
 LargeObjectSpace::LargeObjectSpace(Heap* heap)
-    : Space(heap, LO_SPACE),  // Managed on a per-allocation basis
+    : LargeObjectSpace(heap, LO_SPACE) {}
+
+LargeObjectSpace::LargeObjectSpace(Heap* heap, AllocationSpace id)
+    : Space(heap, id),
       size_(0),
       page_count_(0),
       objects_size_(0),
@@ -3547,5 +3550,13 @@ void Page::Print() {
 }
 
 #endif  // DEBUG
+
+NewLargeObjectSpace::NewLargeObjectSpace(Heap* heap)
+    : LargeObjectSpace(heap, NEW_LO_SPACE) {}
+
+size_t NewLargeObjectSpace::Available() {
+  // TODO(hpayer): Update as soon as we have a growing strategy.
+  return 0;
+}
 }  // namespace internal
 }  // namespace v8

src/heap/spaces.h

@@ -2946,6 +2946,8 @@ class LargeObjectSpace : public Space {
   typedef LargePageIterator iterator;
 
   explicit LargeObjectSpace(Heap* heap);
+  LargeObjectSpace(Heap* heap, AllocationSpace id);
+
   ~LargeObjectSpace() override { TearDown(); }
 
   // Releases internal resources, frees objects in this space.
@@ -3039,6 +3041,13 @@ class LargeObjectSpace : public Space {
   friend class LargeObjectIterator;
 };
 
+class NewLargeObjectSpace : public LargeObjectSpace {
+ public:
+  explicit NewLargeObjectSpace(Heap* heap);
+
+  // Available bytes for objects in this space.
+  size_t Available() override;
+};
 
 class LargeObjectIterator : public ObjectIterator {
  public:

src/snapshot/serializer-common.h

@@ -105,8 +105,12 @@ class SerializerDeserializer : public RootVisitor {
   // No reservation for large object space necessary.
   // We also handle map space differenly.
   STATIC_ASSERT(MAP_SPACE == CODE_SPACE + 1);
+
+  // We do not support young generation large objects.
+  STATIC_ASSERT(LAST_SPACE == NEW_LO_SPACE);
+  STATIC_ASSERT(LAST_SPACE - 1 == LO_SPACE);
   static const int kNumberOfPreallocatedSpaces = CODE_SPACE + 1;
-  static const int kNumberOfSpaces = LAST_SPACE + 1;
+  static const int kNumberOfSpaces = LO_SPACE + 1;
 
  protected:
   static bool CanBeDeferred(HeapObject* o);

src/snapshot/serializer.cc

@@ -647,6 +647,7 @@ void Serializer<AllocatorT>::ObjectSerializer::SerializeObject() {
   Map* map = object_->map();
   AllocationSpace space =
       MemoryChunk::FromAddress(object_->address())->owner()->identity();
+  DCHECK(space != NEW_LO_SPACE);
   SerializePrologue(space, size, map);
 
   // Serialize the rest of the object.

test/cctest/heap/test-heap.cc

@@ -5656,6 +5656,18 @@ TEST(Regress618958) {
          !heap->incremental_marking()->IsStopped()));
 }
 
+TEST(YoungGenerationLargeObjectAllocation) {
+  FLAG_young_generation_large_objects = true;
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = heap->isolate();
+
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(200000);
+  MemoryChunk* chunk = MemoryChunk::FromAddress(array->address());
+  CHECK(chunk->owner()->identity() == NEW_LO_SPACE);
+}
+
 TEST(UncommitUnusedLargeObjectMemory) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());

test/cctest/test-api.cc

@@ -18922,6 +18922,9 @@ TEST(GetHeapSpaceStatistics) {
     v8::HeapSpaceStatistics space_statistics;
     isolate->GetHeapSpaceStatistics(&space_statistics, i);
     CHECK_NOT_NULL(space_statistics.space_name());
+    if (strcmp(space_statistics.space_name(), "new_large_object_space") == 0) {
+      continue;
+    }
     CHECK_GT(space_statistics.space_size(), 0u);
     total_size += space_statistics.space_size();
     CHECK_GT(space_statistics.space_used_size(), 0u);