[heap] Add concurrent marking write barrier

A LocalHeap creates and owns an instance of MarkingBarrier. A pointer to
the marking barrier is set to a thread_local variable for a quick access.

WriteBarrier::MarkingSlow fetches the thread_local variable and invokes
the write barrier if it is set. Otherwise, it invokes the main thread
heap()->marking_barrier().

Each marking barrier has its own local marking worklist that is
published during scavenge (for updating pointers) and at finalization
of incremental marking.

Typed-slot recording does not work yet because it is not thread-safe.
It will be fixed in a subsequent CL.

Bug: v8:10315
Change-Id: I221a906436cd91e7405a253ce0eb06cf68046f2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2354809
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69448}

src/heap/heap-write-barrier.cc

@@ -14,26 +14,51 @@
 namespace v8 {
 namespace internal {
 
+namespace {
+thread_local MarkingBarrier* current_marking_barrier = nullptr;
+}  // namespace
+
+void WriteBarrier::SetForThread(MarkingBarrier* marking_barrier) {
+  DCHECK_NULL(current_marking_barrier);
+  current_marking_barrier = marking_barrier;
+}
+
+void WriteBarrier::ClearForThread(MarkingBarrier* marking_barrier) {
+  DCHECK_EQ(current_marking_barrier, marking_barrier);
+  current_marking_barrier = nullptr;
+}
+
 void WriteBarrier::MarkingSlow(Heap* heap, HeapObject host, HeapObjectSlot slot,
                                HeapObject value) {
-  heap->marking_barrier()->Write(host, slot, value);
+  MarkingBarrier* marking_barrier = current_marking_barrier
+                                        ? current_marking_barrier
+                                        : heap->marking_barrier();
+  marking_barrier->Write(host, slot, value);
 }
 
 void WriteBarrier::MarkingSlow(Heap* heap, Code host, RelocInfo* reloc_info,
                                HeapObject value) {
-  heap->marking_barrier()->Write(host, reloc_info, value);
+  MarkingBarrier* marking_barrier = current_marking_barrier
+                                        ? current_marking_barrier
+                                        : heap->marking_barrier();
+  marking_barrier->Write(host, reloc_info, value);
 }
 
 void WriteBarrier::MarkingSlow(Heap* heap, JSArrayBuffer host,
                                ArrayBufferExtension* extension) {
-  heap->marking_barrier()->Write(host, extension);
+  MarkingBarrier* marking_barrier = current_marking_barrier
+                                        ? current_marking_barrier
+                                        : heap->marking_barrier();
+  marking_barrier->Write(host, extension);
 }
 
 void WriteBarrier::MarkingSlow(Heap* heap, Map host,
                                DescriptorArray descriptor_array,
                                int number_of_own_descriptors) {
-  heap->marking_barrier()->Write(host, descriptor_array,
-                                 number_of_own_descriptors);
+  MarkingBarrier* marking_barrier = current_marking_barrier
+                                        ? current_marking_barrier
+                                        : heap->marking_barrier();
+  marking_barrier->Write(host, descriptor_array, number_of_own_descriptors);
 }
 
 int WriteBarrier::MarkingFromCode(Address raw_host, Address raw_slot) {

src/heap/heap-write-barrier.h

@@ -21,6 +21,7 @@ class Heap;
 class JSArrayBuffer;
 class Map;
 class MarkCompactCollector;
+class MarkingBarrier;
 class RelocInfo;
 
 // Note: In general it is preferred to use the macros defined in
@@ -55,6 +56,9 @@ class V8_EXPORT_PRIVATE WriteBarrier {
   // It is invoked from generated code and has to take raw addresses.
   static int MarkingFromCode(Address raw_host, Address raw_slot);
 
+  static void SetForThread(MarkingBarrier*);
+  static void ClearForThread(MarkingBarrier*);
+
  private:
   static void MarkingSlow(Heap* heap, HeapObject host, HeapObjectSlot,
                           HeapObject value);

src/heap/heap.cc

@@ -5251,8 +5251,7 @@ void Heap::SetUp() {
     concurrent_marking_.reset(new ConcurrentMarking(this, nullptr, nullptr));
   }
 
-  marking_barrier_.reset(new MarkingBarrier(this, mark_compact_collector(),
-                                            incremental_marking()));
+  marking_barrier_.reset(new MarkingBarrier(this));
 
   for (int i = FIRST_SPACE; i <= LAST_SPACE; i++) {
     space_[i] = nullptr;

src/heap/incremental-marking.cc

@@ -237,7 +237,7 @@ void IncrementalMarking::StartMarking() {
 
   SetState(MARKING);
 
-  heap_->marking_barrier()->Activate(is_compacting_);
+  MarkingBarrier::ActivateAll(heap(), is_compacting_);
 
   heap_->isolate()->compilation_cache()->MarkCompactPrologue();
 
@@ -412,6 +412,8 @@ void IncrementalMarking::FinalizeIncrementally() {
   // so we can do it only once at the beginning of the finalization.
   RetainMaps();
 
+  MarkingBarrier::PublishAll(heap());
+
   finalize_marking_completed_ = true;
 
   if (FLAG_trace_incremental_marking) {
@@ -433,6 +435,7 @@ void IncrementalMarking::UpdateMarkingWorklistAfterScavenge() {
 #endif  // ENABLE_MINOR_MC
 
   collector_->local_marking_worklists()->Publish();
+  MarkingBarrier::PublishAll(heap());
   collector_->marking_worklists()->Update(
       [
 #ifdef DEBUG

src/heap/incremental-marking.h

@@ -251,6 +251,8 @@ class V8_EXPORT_PRIVATE IncrementalMarking final {
   // increase chances of reusing of map transition tree in future.
   void RetainMaps();
 
+  void PublishWriteBarrierWorklists();
+
   // Updates scheduled_bytes_to_mark_ to ensure marking progress based on
   // time.
   void ScheduleBytesToMarkBasedOnTime(double time_ms);

src/heap/local-heap.cc

@@ -10,7 +10,9 @@
 #include "src/common/globals.h"
 #include "src/handles/local-handles.h"
 #include "src/heap/heap-inl.h"
+#include "src/heap/heap-write-barrier.h"
 #include "src/heap/local-heap-inl.h"
+#include "src/heap/marking-barrier.h"
 #include "src/heap/safepoint.h"
 
 namespace v8 {
@@ -32,6 +34,7 @@ LocalHeap::LocalHeap(Heap* heap,
       next_(nullptr),
       handles_(new LocalHandles),
       persistent_handles_(std::move(persistent_handles)),
+      marking_barrier_(new MarkingBarrier(this)),
       old_space_allocator_(this, heap->old_space()) {
   heap_->safepoint()->AddLocalHeap(this);
   if (persistent_handles_) {
@@ -39,9 +42,15 @@ LocalHeap::LocalHeap(Heap* heap,
   }
   DCHECK_NULL(current_local_heap);
   current_local_heap = this;
+  WriteBarrier::SetForThread(marking_barrier_.get());
+  if (heap_->incremental_marking()->IsMarking()) {
+    marking_barrier_->Activate(heap_->incremental_marking()->IsCompacting());
+  }
 }
 
 LocalHeap::~LocalHeap() {
+  marking_barrier_->Publish();
+  WriteBarrier::ClearForThread(marking_barrier_.get());
   // Give up LAB before parking thread
   old_space_allocator_.FreeLinearAllocationArea();
 

src/heap/local-heap.h

@@ -76,6 +76,7 @@ class V8_EXPORT_PRIVATE LocalHeap {
 
   Heap* heap() { return heap_; }
 
+  MarkingBarrier* marking_barrier() { return marking_barrier_.get(); }
   ConcurrentAllocator* old_space_allocator() { return &old_space_allocator_; }
 
   // Mark/Unmark linear allocation areas black. Used for black allocation.
@@ -155,6 +156,7 @@ class V8_EXPORT_PRIVATE LocalHeap {
 
   std::unique_ptr<LocalHandles> handles_;
   std::unique_ptr<PersistentHandles> persistent_handles_;
+  std::unique_ptr<MarkingBarrier> marking_barrier_;
 
   ConcurrentAllocator old_space_allocator_;
 

src/heap/mark-compact.cc

@@ -456,6 +456,8 @@ void MarkCompactCollector::TearDown() {
   AbortWeakObjects();
   if (heap()->incremental_marking()->IsMarking()) {
     local_marking_worklists()->Publish();
+    heap()->marking_barrier()->Publish();
+    // Marking barriers of LocalHeaps will be published in their destructors.
     marking_worklists()->Clear();
   }
 }
@@ -1954,6 +1956,7 @@ void MarkCompactCollector::MarkLiveObjects() {
     IncrementalMarking* incremental_marking = heap_->incremental_marking();
     if (was_marked_incrementally_) {
       incremental_marking->Finalize();
+      MarkingBarrier::DeactivateAll(heap());
     } else {
       CHECK(incremental_marking->IsStopped());
     }
@@ -2058,10 +2061,6 @@ void MarkCompactCollector::MarkLiveObjects() {
     }
   }
 
-  if (was_marked_incrementally_) {
-    heap()->marking_barrier()->Deactivate();
-  }
-
   epoch_++;
 }
 

src/heap/marking-barrier-inl.h

@@ -27,7 +27,7 @@ bool MarkingBarrier::MarkValue(HeapObject host, HeapObject value) {
     // visits the host object.
     return false;
   }
-  if (WhiteToGreyAndPush(value)) {
+  if (WhiteToGreyAndPush(value) && is_main_thread_barrier_) {
     incremental_marking_->RestartIfNotMarking();
   }
   return true;
@@ -35,7 +35,7 @@ bool MarkingBarrier::MarkValue(HeapObject host, HeapObject value) {
 
 bool MarkingBarrier::WhiteToGreyAndPush(HeapObject obj) {
   if (marking_state_.WhiteToGrey(obj)) {
-    collector_->local_marking_worklists()->Push(obj);
+    worklist_.Push(obj);
     return true;
   }
   return false;

src/heap/marking-barrier.cc

@@ -11,16 +11,29 @@
 #include "src/heap/mark-compact-inl.h"
 #include "src/heap/mark-compact.h"
 #include "src/heap/marking-barrier-inl.h"
+#include "src/heap/marking-worklist-inl.h"
+#include "src/heap/marking-worklist.h"
+#include "src/heap/safepoint.h"
 #include "src/objects/js-array-buffer.h"
 
 namespace v8 {
 namespace internal {
 
-MarkingBarrier::MarkingBarrier(Heap* heap, MarkCompactCollector* collector,
-                               IncrementalMarking* incremental_marking)
+MarkingBarrier::MarkingBarrier(Heap* heap)
     : heap_(heap),
-      collector_(collector),
-      incremental_marking_(incremental_marking) {}
+      collector_(heap_->mark_compact_collector()),
+      incremental_marking_(heap_->incremental_marking()),
+      worklist_(collector_->marking_worklists()->shared()),
+      is_main_thread_barrier_(true) {}
+
+MarkingBarrier::MarkingBarrier(LocalHeap* local_heap)
+    : heap_(local_heap->heap()),
+      collector_(heap_->mark_compact_collector()),
+      incremental_marking_(nullptr),
+      worklist_(collector_->marking_worklists()->shared()),
+      is_main_thread_barrier_(false) {}
+
+MarkingBarrier::~MarkingBarrier() { DCHECK(worklist_.IsLocalEmpty()); }
 
 void MarkingBarrier::Write(HeapObject host, HeapObjectSlot slot,
                            HeapObject value) {
@@ -32,6 +45,7 @@ void MarkingBarrier::Write(HeapObject host, HeapObjectSlot slot,
 }
 
 void MarkingBarrier::Write(Code host, RelocInfo* reloc_info, HeapObject value) {
+  DCHECK(is_main_thread_barrier_);
   if (MarkValue(host, value)) {
     if (is_compacting_) {
       collector_->RecordRelocSlot(host, reloc_info, value);
@@ -41,6 +55,7 @@ void MarkingBarrier::Write(Code host, RelocInfo* reloc_info, HeapObject value) {
 
 void MarkingBarrier::Write(JSArrayBuffer host,
                            ArrayBufferExtension* extension) {
+  DCHECK(is_main_thread_barrier_);
   if (!V8_CONCURRENT_MARKING_BOOL && marking_state_.IsBlack(host)) {
     // The extension will be marked when the marker visits the host object.
     return;
@@ -50,6 +65,7 @@ void MarkingBarrier::Write(JSArrayBuffer host,
 
 void MarkingBarrier::Write(Map host, DescriptorArray descriptor_array,
                            int number_of_own_descriptors) {
+  DCHECK(is_main_thread_barrier_);
   int16_t raw_marked = descriptor_array.raw_number_of_marked_descriptors();
   if (NumberOfMarkedDescriptors::decode(collector_->epoch(), raw_marked) <
       number_of_own_descriptors) {
@@ -58,44 +74,89 @@ void MarkingBarrier::Write(Map host, DescriptorArray descriptor_array,
   }
 }
 
-void MarkingBarrier::Deactivate(PagedSpace* space) {
+// static
+void MarkingBarrier::ActivateAll(Heap* heap, bool is_compacting) {
+  heap->marking_barrier()->Activate(is_compacting);
+  if (FLAG_local_heaps) {
+    heap->safepoint()->IterateLocalHeaps(
+        [is_compacting](LocalHeap* local_heap) {
+          local_heap->marking_barrier()->Activate(is_compacting);
+        });
+  }
+}
+
+// static
+void MarkingBarrier::DeactivateAll(Heap* heap) {
+  heap->marking_barrier()->Deactivate();
+  if (FLAG_local_heaps) {
+    heap->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
+      local_heap->marking_barrier()->Deactivate();
+    });
+  }
+}
+
+// static
+void MarkingBarrier::PublishAll(Heap* heap) {
+  heap->marking_barrier()->Publish();
+  if (FLAG_local_heaps) {
+    heap->safepoint()->IterateLocalHeaps([](LocalHeap* local_heap) {
+      local_heap->marking_barrier()->Publish();
+    });
+  }
+}
+
+void MarkingBarrier::Publish() {
+  if (is_activated_) {
+    worklist_.Publish();
+  }
+}
+
+void MarkingBarrier::DeactivateSpace(PagedSpace* space) {
+  DCHECK(is_main_thread_barrier_);
   for (Page* p : *space) {
     p->SetOldGenerationPageFlags(false);
   }
 }
 
-void MarkingBarrier::Deactivate(NewSpace* space) {
+void MarkingBarrier::DeactivateSpace(NewSpace* space) {
+  DCHECK(is_main_thread_barrier_);
   for (Page* p : *space) {
     p->SetYoungGenerationPageFlags(false);
   }
 }
 
 void MarkingBarrier::Deactivate() {
-  Deactivate(heap_->old_space());
-  Deactivate(heap_->map_space());
-  Deactivate(heap_->code_space());
-  Deactivate(heap_->new_space());
-  for (LargePage* p : *heap_->new_lo_space()) {
-    p->SetYoungGenerationPageFlags(false);
-    DCHECK(p->IsLargePage());
-  }
-  for (LargePage* p : *heap_->lo_space()) {
-    p->SetOldGenerationPageFlags(false);
-  }
-  for (LargePage* p : *heap_->code_lo_space()) {
-    p->SetOldGenerationPageFlags(false);
-  }
+  Publish();
   is_activated_ = false;
   is_compacting_ = false;
+  if (is_main_thread_barrier_) {
+    DeactivateSpace(heap_->old_space());
+    DeactivateSpace(heap_->map_space());
+    DeactivateSpace(heap_->code_space());
+    DeactivateSpace(heap_->new_space());
+    for (LargePage* p : *heap_->new_lo_space()) {
+      p->SetYoungGenerationPageFlags(false);
+      DCHECK(p->IsLargePage());
+    }
+    for (LargePage* p : *heap_->lo_space()) {
+      p->SetOldGenerationPageFlags(false);
+    }
+    for (LargePage* p : *heap_->code_lo_space()) {
+      p->SetOldGenerationPageFlags(false);
+    }
+  }
+  DCHECK(worklist_.IsLocalEmpty());
 }
 
-void MarkingBarrier::Activate(PagedSpace* space) {
+void MarkingBarrier::ActivateSpace(PagedSpace* space) {
+  DCHECK(is_main_thread_barrier_);
   for (Page* p : *space) {
     p->SetOldGenerationPageFlags(true);
   }
 }
 
-void MarkingBarrier::Activate(NewSpace* space) {
+void MarkingBarrier::ActivateSpace(NewSpace* space) {
+  DCHECK(is_main_thread_barrier_);
   for (Page* p : *space) {
     p->SetYoungGenerationPageFlags(true);
   }
@@ -103,24 +164,27 @@ void MarkingBarrier::Activate(NewSpace* space) {
 
 void MarkingBarrier::Activate(bool is_compacting) {
   DCHECK(!is_activated_);
+  DCHECK(worklist_.IsLocalEmpty());
   is_compacting_ = is_compacting;
   is_activated_ = true;
-  Activate(heap_->old_space());
-  Activate(heap_->map_space());
-  Activate(heap_->code_space());
-  Activate(heap_->new_space());
+  if (is_main_thread_barrier_) {
+    ActivateSpace(heap_->old_space());
+    ActivateSpace(heap_->map_space());
+    ActivateSpace(heap_->code_space());
+    ActivateSpace(heap_->new_space());
 
-  for (LargePage* p : *heap_->new_lo_space()) {
-    p->SetYoungGenerationPageFlags(true);
-    DCHECK(p->IsLargePage());
-  }
+    for (LargePage* p : *heap_->new_lo_space()) {
+      p->SetYoungGenerationPageFlags(true);
+      DCHECK(p->IsLargePage());
+    }
 
-  for (LargePage* p : *heap_->lo_space()) {
-    p->SetOldGenerationPageFlags(true);
-  }
+    for (LargePage* p : *heap_->lo_space()) {
+      p->SetOldGenerationPageFlags(true);
+    }
 
-  for (LargePage* p : *heap_->code_lo_space()) {
-    p->SetOldGenerationPageFlags(true);
+    for (LargePage* p : *heap_->code_lo_space()) {
+      p->SetOldGenerationPageFlags(true);
+    }
   }
 }
 

src/heap/marking-barrier.h

@@ -14,14 +14,23 @@ namespace internal {
 
 class Heap;
 class IncrementalMarking;
+class LocalHeap;
 class PagedSpace;
 class NewSpace;
 
 class MarkingBarrier {
  public:
-  MarkingBarrier(Heap*, MarkCompactCollector*, IncrementalMarking*);
+  explicit MarkingBarrier(Heap*);
+  explicit MarkingBarrier(LocalHeap*);
+  ~MarkingBarrier();
+
   void Activate(bool is_compacting);
   void Deactivate();
+  void Publish();
+
+  static void ActivateAll(Heap* heap, bool is_compacting);
+  static void DeactivateAll(Heap* heap);
+  static void PublishAll(Heap* heap);
 
   void Write(HeapObject host, HeapObjectSlot, HeapObject value);
   void Write(Code host, RelocInfo*, HeapObject value);
@@ -36,18 +45,20 @@ class MarkingBarrier {
 
   inline bool WhiteToGreyAndPush(HeapObject value);
 
-  void Activate(PagedSpace*);
-  void Activate(NewSpace*);
+  void ActivateSpace(PagedSpace*);
+  void ActivateSpace(NewSpace*);
 
-  void Deactivate(PagedSpace*);
-  void Deactivate(NewSpace*);
+  void DeactivateSpace(PagedSpace*);
+  void DeactivateSpace(NewSpace*);
 
-  MarkingState marking_state_;
   Heap* heap_;
   MarkCompactCollector* collector_;
   IncrementalMarking* incremental_marking_;
+  MarkingWorklist::Local worklist_;
+  MarkingState marking_state_;
   bool is_compacting_ = false;
   bool is_activated_ = false;
+  bool is_main_thread_barrier_;
 };
 
 }  // namespace internal

test/cctest/heap/test-concurrent-allocation.cc

@@ -250,5 +250,60 @@ UNINITIALIZED_TEST(ConcurrentBlackAllocation) {
   isolate->Dispose();
 }
 
+class ConcurrentWriteBarrierThread final : public v8::base::Thread {
+ public:
+  explicit ConcurrentWriteBarrierThread(Heap* heap, FixedArray fixed_array,
+                                        HeapObject value)
+      : v8::base::Thread(base::Thread::Options("ThreadWithLocalHeap")),
+        heap_(heap),
+        fixed_array_(fixed_array),
+        value_(value) {}
+
+  void Run() override {
+    LocalHeap local_heap(heap_);
+    fixed_array_.set(0, value_);
+  }
+
+  Heap* heap_;
+  FixedArray fixed_array_;
+  HeapObject value_;
+};
+
+UNINITIALIZED_TEST(ConcurrentWriteBarrier) {
+  ManualGCScope manual_gc_scope;
+  FLAG_concurrent_allocation = true;
+  FLAG_local_heaps = true;
+
+  v8::Isolate::CreateParams create_params;
+  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
+  v8::Isolate* isolate = v8::Isolate::New(create_params);
+  Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+  Heap* heap = i_isolate->heap();
+
+  FixedArray fixed_array;
+  HeapObject value;
+  {
+    HandleScope handle_scope(i_isolate);
+    Handle<FixedArray> fixed_array_handle(
+        i_isolate->factory()->NewFixedArray(1));
+    Handle<HeapNumber> value_handle(i_isolate->factory()->NewHeapNumber(1.1));
+    fixed_array = *fixed_array_handle;
+    value = *value_handle;
+  }
+  heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
+                                i::GarbageCollectionReason::kTesting);
+  CHECK(heap->incremental_marking()->marking_state()->IsWhite(value));
+
+  auto thread =
+      std::make_unique<ConcurrentWriteBarrierThread>(heap, fixed_array, value);
+  CHECK(thread->Start());
+
+  thread->Join();
+
+  CHECK(heap->incremental_marking()->marking_state()->IsBlackOrGrey(value));
+
+  isolate->Dispose();
+}
+
 }  // namespace internal
 }  // namespace v8