[heap] Fine-grained JSArrayBuffer tracking

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/frames-inl.h"
 #include "src/gdb-jit.h"
 #include "src/global-handles.h"
-#include "src/heap/array-buffer-tracker.h"
+#include "src/heap/array-buffer-tracker-inl.h"
 #include "src/heap/gc-tracer.h"
 #include "src/heap/incremental-marking.h"
 #include "src/heap/mark-compact-inl.h"
 #include "src/heap/object-stats.h"
 #include "src/heap/objects-visiting-inl.h"
 #include "src/heap/objects-visiting.h"
 #include "src/heap/page-parallel-job.h"
 #include "src/heap/spaces-inl.h"
 #include "src/ic/ic.h"
 #include "src/ic/stub-cache.h"
@@ skipping 835 matching lines @@
   // marking cycle. We did not collect any slots.
   if (!FLAG_never_compact && !was_marked_incrementally_) {
     StartCompaction(NON_INCREMENTAL_COMPACTION);
   }
 
   PagedSpaces spaces(heap());
   for (PagedSpace* space = spaces.next(); space != NULL;
        space = spaces.next()) {
     space->PrepareForMarkCompact();
   }
+  if (!was_marked_incrementally_) {
+    heap()->old_space()->ForAllPages([](Page* p) { p->ResetTracker(); });
+  }
+  heap()->account_amount_of_external_allocated_freed_memory();
 
 #ifdef VERIFY_HEAP
   if (!was_marked_incrementally_ && FLAG_verify_heap) {
     VerifyMarkbitsAreClean();
   }
 #endif
 }
 
 
 void MarkCompactCollector::Finish() {
@@ skipping 835 matching lines @@
         local_pretenuring_feedback_(local_pretenuring_feedback) {}
 
   inline bool Visit(HeapObject* object) override {
     heap_->UpdateAllocationSite<Heap::kCached>(object,
                                                local_pretenuring_feedback_);
     int size = object->Size();
     HeapObject* target_object = nullptr;
     if (heap_->ShouldBePromoted(object->address(), size) &&
         TryEvacuateObject(compaction_spaces_->Get(OLD_SPACE), object,
                           &target_object)) {
-      // If we end up needing more special cases, we should factor this out.

[Hannes Payer (out of office), 2016/05/20 12:21:17]

Nice!

-      if (V8_UNLIKELY(target_object->IsJSArrayBuffer())) {
-        heap_->array_buffer_tracker()->Promote(
-            JSArrayBuffer::cast(target_object));
-      }
       promoted_size_ += size;
       return true;
     }
     HeapObject* target = nullptr;
     AllocationSpace space = AllocateTargetObject(object, &target);
     MigrateObject(HeapObject::cast(target), object, size, space);
-    if (V8_UNLIKELY(target->IsJSArrayBuffer())) {
-      heap_->array_buffer_tracker()->MarkLive(JSArrayBuffer::cast(target));
-    }
     semispace_copied_size_ += size;
     return true;
   }
 
   intptr_t promoted_size() { return promoted_size_; }
   intptr_t semispace_copied_size() { return semispace_copied_size_; }
 
  private:
   enum NewSpaceAllocationMode {
     kNonstickyBailoutOldSpace,
@@ skipping 104 matching lines @@
       : heap_(heap), promoted_size_(0) {}
 
   static void TryMoveToOldSpace(Page* page, PagedSpace* owner) {
     if (page->heap()->new_space()->ReplaceWithEmptyPage(page)) {
       Page* new_page = Page::ConvertNewToOld(page, owner);
       new_page->SetFlag(Page::PAGE_NEW_OLD_PROMOTION);
     }
   }
 
   inline bool Visit(HeapObject* object) {
-    if (V8_UNLIKELY(object->IsJSArrayBuffer())) {
-      object->GetHeap()->array_buffer_tracker()->Promote(
-          JSArrayBuffer::cast(object));
-    }
     RecordMigratedSlotVisitor visitor(heap_->mark_compact_collector());
     object->IterateBodyFast(&visitor);
     promoted_size_ += object->Size();
     return true;
   }
 
   intptr_t promoted_size() { return promoted_size_; }
 
  private:
   Heap* heap_;
@@ skipping 20 matching lines @@
 };
 
 class MarkCompactCollector::EvacuateRecordOnlyVisitor final
     : public MarkCompactCollector::HeapObjectVisitor {
  public:
   explicit EvacuateRecordOnlyVisitor(Heap* heap) : heap_(heap) {}
 
   inline bool Visit(HeapObject* object) {
     RecordMigratedSlotVisitor visitor(heap_->mark_compact_collector());
     object->IterateBody(&visitor);
+    if (V8_UNLIKELY(object->IsJSArrayBuffer())) {
+      heap_->array_buffer_tracker()->MarkLive(JSArrayBuffer::cast(object));
+    }
     return true;
   }
 
  private:
   Heap* heap_;
 };
 
 void MarkCompactCollector::DiscoverGreyObjectsInSpace(PagedSpace* space) {
   PageIterator it(space);
   while (it.has_next()) {
@@ skipping 1306 matching lines @@
   }
   return success;
 }
 
 bool MarkCompactCollector::Evacuator::EvacuatePage(Page* page) {
   bool result = false;
   DCHECK(page->SweepingDone());
   switch (ComputeEvacuationMode(page)) {
     case kObjectsNewToOld:
       result = EvacuateSinglePage<kClearMarkbits>(page, &new_space_visitor_);
+      page->ScanAndFreeDeadArrayBuffers<
+          LocalArrayBufferTracker::kForwardingPointer>();
       DCHECK(result);
       USE(result);
       break;
     case kPageNewToOld:
       result = EvacuateSinglePage<kKeepMarking>(page, &new_space_page_visitor);
+      // ArrayBufferTracker will be updated during sweeping.
       DCHECK(result);
       USE(result);
       break;
     case kObjectsOldToOld:
       result = EvacuateSinglePage<kClearMarkbits>(page, &old_space_visitor_);
+      page->ScanAndFreeDeadArrayBuffers<
+          LocalArrayBufferTracker::kForwardingPointer>();
       if (!result) {
         // Aborted compaction page. We can record slots here to have them
         // processed in parallel later on.
         EvacuateRecordOnlyVisitor record_visitor(collector_->heap());
         result = EvacuateSinglePage<kKeepMarking>(page, &record_visitor);
+        page->ScanAndFreeDeadArrayBuffers<LocalArrayBufferTracker::kMarkBit>();
         DCHECK(result);
         USE(result);
         // We need to return failure here to indicate that we want this page
         // added to the sweeper.
         return false;
       }
       break;
     default:
       UNREACHABLE();
   }
@@ skipping 221 matching lines @@
   Bitmap::Clear(p);
 
   if (free_start != p->area_end()) {
     int size = static_cast<int>(p->area_end() - free_start);
     if (free_space_mode == ZAP_FREE_SPACE) {
       memset(free_start, 0xcc, size);
     }
     freed_bytes = space->UnaccountedFree(free_start, size);
     max_freed_bytes = Max(freed_bytes, max_freed_bytes);
   }
+  p->FreeDeadArrayBuffers();
   p->concurrent_sweeping_state().SetValue(Page::kSweepingDone);
   return FreeList::GuaranteedAllocatable(static_cast<int>(max_freed_bytes));
 }
 
 void MarkCompactCollector::InvalidateCode(Code* code) {
   if (heap_->incremental_marking()->IsCompacting() &&
       !ShouldSkipEvacuationSlotRecording(code)) {
     DCHECK(compacting_);
 
     // If the object is white than no slots were recorded on it yet.
@@ skipping 122 matching lines @@
       // because root iteration traverses the stack and might have to find
       // code objects from non-updated pc pointing into evacuation candidate.
       SkipList* list = p->skip_list();
       if (list != NULL) list->Clear();
       if (p->IsFlagSet(Page::COMPACTION_WAS_ABORTED)) {
         sweeper().AddLatePage(p->owner()->identity(), p);
         p->ClearFlag(Page::COMPACTION_WAS_ABORTED);
       }
     }
 
-    // EvacuateNewSpaceAndCandidates iterates over new space objects and for
-    // ArrayBuffers either re-registers them as live or promotes them. This is
-    // needed to properly free them.
-    heap()->array_buffer_tracker()->FreeDead(false);
-
     // Deallocate evacuated candidate pages.
     ReleaseEvacuationCandidates();
   }
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap && !sweeper().sweeping_in_progress()) {
     VerifyEvacuation(heap());
   }
 #endif
 }
@@ skipping 384 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8