Reland "[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"
@@ skipping 854 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();
   }
+  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.
-      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 1238 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_);
+      ArrayBufferTracker::ProcessBuffers(
+          page, ArrayBufferTracker::kUpdateForwardedRemoveOthers);
       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_);
       if (!result) {
         // Aborted compaction page. We have to record slots here, since we might
         // not have recorded them in first place.
         // Note: We mark the page as aborted here to be able to record slots
         // for code objects in |RecordMigratedSlotVisitor|.
         page->SetFlag(Page::COMPACTION_WAS_ABORTED);
         EvacuateRecordOnlyVisitor record_visitor(collector_->heap());
         result = EvacuateSinglePage<kKeepMarking>(page, &record_visitor);
+        ArrayBufferTracker::ProcessBuffers(
+            page, ArrayBufferTracker::kUpdateForwardedKeepOthers);
         DCHECK(result);
         USE(result);
         // We need to return failure here to indicate that we want this page
         // added to the sweeper.
         return false;
       }
+      ArrayBufferTracker::ProcessBuffers(
+          page, ArrayBufferTracker::kUpdateForwardedRemoveOthers);
+
       break;
     default:
       UNREACHABLE();
   }
   return result;
 }
 
 void MarkCompactCollector::Evacuator::Finalize() {
   heap()->old_space()->MergeCompactionSpace(compaction_spaces_.Get(OLD_SPACE));
   heap()->code_space()->MergeCompactionSpace(
@@ skipping 158 matching lines @@
           MarkCompactCollector::Sweeper::SkipListRebuildingMode skip_list_mode,
           MarkCompactCollector::Sweeper::FreeSpaceTreatmentMode free_space_mode>
 int MarkCompactCollector::Sweeper::RawSweep(PagedSpace* space, Page* p,
                                             ObjectVisitor* v) {
   DCHECK(!p->IsEvacuationCandidate() && !p->SweepingDone());
   DCHECK(!p->IsFlagSet(Page::BLACK_PAGE));
   DCHECK_EQ(skip_list_mode == REBUILD_SKIP_LIST,
             space->identity() == CODE_SPACE);
   DCHECK((p->skip_list() == NULL) || (skip_list_mode == REBUILD_SKIP_LIST));
   DCHECK(parallelism == SWEEP_ON_MAIN_THREAD || sweeping_mode == SWEEP_ONLY);
 

[Hannes Payer (out of office), 2016/06/01 13:44:17]

// Before we sweep objects on the page, we free dead array buffers which
requires valid mark bits.

[Michael Lippautz, 2016/06/01 14:19:19]

Done.

+  ArrayBufferTracker::FreeDead(p);
+
   Address free_start = p->area_start();
   DCHECK(reinterpret_cast<intptr_t>(free_start) % (32 * kPointerSize) == 0);
 
   // If we use the skip list for code space pages, we have to lock the skip
   // list because it could be accessed concurrently by the runtime or the
   // deoptimizer.
   SkipList* skip_list = p->skip_list();
   if ((skip_list_mode == REBUILD_SKIP_LIST) && skip_list) {
     skip_list->Clear();
   }
@@ skipping 179 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 405 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