Revert "[heap] Move pointers updating to ItemParallelJob"

This reverts commit 81d3427b.

Reason for revert: Several gc related failures, e.g.:
https://build.chromium.org/p/client.v8/builders/V8%20Mac%20GC%20Stress/builds/13488

Original change's description:
> [heap] Move pointers updating to ItemParallelJob
> 
> Furthermore avoid lock-step between pointer updating phases as they
> should execute in parallel without synchronization restrictions.
> 
> Bug: chromium:726040
> Change-Id: I26ce0d1f2a4637ff5610cae556113e3d736788e2
> Reviewed-on: https://chromium-review.googlesource.com/518103
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45574}

NOPRESUBMIT=true
NOTRY=true
NOTREECHECKS=true

TBR=ulan@chromium.org,hpayer@chromium.org,mlippautz@chromium.org
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:726040

Change-Id: I60860aef390605d07bc520141cab9d5be9b712b3
Reviewed-on: https://chromium-review.googlesource.com/518106
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45575}

src/heap/gc-tracer.cc

@@ -538,8 +538,10 @@ void GCTracer::PrintNVP() const {
           "evacuate=%.2f "
           "evacuate.copy=%.2f "
           "evacuate.update_pointers=%.2f "
-          "evacuate.update_pointers.to_new_roots=%.2f "
-          "evacuate.update_pointers.slots=%.2f "
+          "evacuate.update_pointers.to_new=%.2f "
+          "evacuate.update_pointers.to_new.tospace=%.2f "
+          "evacuate.update_pointers.to_new.roots=%.2f "
+          "evacuate.update_pointers.to_new.old=%.2f "
           "update_marking_deque=%.2f "
           "reset_liveness=%.2f\n",
           duration, spent_in_mutator, "mmc", current_.reduce_memory,
@@ -556,9 +558,12 @@ void GCTracer::PrintNVP() const {
           current_.scopes[Scope::MINOR_MC_EVACUATE],
           current_.scopes[Scope::MINOR_MC_EVACUATE_COPY],
           current_.scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS],
+          current_.scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW],
+          current_
+              .scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_TOSPACE],
           current_
               .scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS],
-          current_.scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_SLOTS],
+          current_.scopes[Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_OLD],
           current_.scopes[Scope::MINOR_MC_MARKING_DEQUE],
           current_.scopes[Scope::MINOR_MC_RESET_LIVENESS]);
       break;
@@ -593,8 +598,8 @@ void GCTracer::PrintNVP() const {
           "evacuate.epilogue=%.1f "
           "evacuate.rebalance=%.1f "
           "evacuate.update_pointers=%.1f "
-          "evacuate.update_pointers.to_new_roots=%.1f "
-          "evacuate.update_pointers.slots=%.1f "
+          "evacuate.update_pointers.to_evacuated=%.1f "
+          "evacuate.update_pointers.to_new=%.1f "
           "evacuate.update_pointers.weak=%.1f "
           "finish=%.1f "
           "mark=%.1f "
@@ -677,8 +682,8 @@ void GCTracer::PrintNVP() const {
           current_.scopes[Scope::MC_EVACUATE_EPILOGUE],
           current_.scopes[Scope::MC_EVACUATE_REBALANCE],
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS],
-          current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS],
-          current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_SLOTS],
+          current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_TO_EVACUATED],
+          current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW],
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_WEAK],
           current_.scopes[Scope::MC_FINISH], current_.scopes[Scope::MC_MARK],
           current_.scopes[Scope::MC_MARK_FINISH_INCREMENTAL],

src/heap/gc-tracer.h

@@ -34,79 +34,81 @@ enum ScavengeSpeedMode { kForAllObjects, kForSurvivedObjects };
   F(MC_INCREMENTAL_EXTERNAL_EPILOGUE)                              \
   F(MC_INCREMENTAL_EXTERNAL_PROLOGUE)
 
-#define TRACER_SCOPES(F)                            \
-  INCREMENTAL_SCOPES(F)                             \
-  F(HEAP_EPILOGUE)                                  \
-  F(HEAP_EPILOGUE_REDUCE_NEW_SPACE)                 \
-  F(HEAP_EXTERNAL_EPILOGUE)                         \
-  F(HEAP_EXTERNAL_PROLOGUE)                         \
-  F(HEAP_EXTERNAL_WEAK_GLOBAL_HANDLES)              \
-  F(HEAP_PROLOGUE)                                  \
-  F(MC_CLEAR)                                       \
-  F(MC_CLEAR_DEPENDENT_CODE)                        \
-  F(MC_CLEAR_MAPS)                                  \
-  F(MC_CLEAR_SLOTS_BUFFER)                          \
-  F(MC_CLEAR_STORE_BUFFER)                          \
-  F(MC_CLEAR_STRING_TABLE)                          \
-  F(MC_CLEAR_WEAK_CELLS)                            \
-  F(MC_CLEAR_WEAK_COLLECTIONS)                      \
-  F(MC_CLEAR_WEAK_LISTS)                            \
-  F(MC_EPILOGUE)                                    \
-  F(MC_EVACUATE)                                    \
-  F(MC_EVACUATE_CANDIDATES)                         \
-  F(MC_EVACUATE_CLEAN_UP)                           \
-  F(MC_EVACUATE_COPY)                               \
-  F(MC_EVACUATE_EPILOGUE)                           \
-  F(MC_EVACUATE_PROLOGUE)                           \
-  F(MC_EVACUATE_REBALANCE)                          \
-  F(MC_EVACUATE_UPDATE_POINTERS)                    \
-  F(MC_EVACUATE_UPDATE_POINTERS_SLOTS)              \
-  F(MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS)       \
-  F(MC_EVACUATE_UPDATE_POINTERS_WEAK)               \
-  F(MC_FINISH)                                      \
-  F(MC_MARK)                                        \
-  F(MC_MARK_FINISH_INCREMENTAL)                     \
-  F(MC_MARK_ROOTS)                                  \
-  F(MC_MARK_WEAK_CLOSURE)                           \
-  F(MC_MARK_WEAK_CLOSURE_EPHEMERAL)                 \
-  F(MC_MARK_WEAK_CLOSURE_WEAK_HANDLES)              \
-  F(MC_MARK_WEAK_CLOSURE_WEAK_ROOTS)                \
-  F(MC_MARK_WEAK_CLOSURE_HARMONY)                   \
-  F(MC_MARK_WRAPPER_EPILOGUE)                       \
-  F(MC_MARK_WRAPPER_PROLOGUE)                       \
-  F(MC_MARK_WRAPPER_TRACING)                        \
-  F(MC_PROLOGUE)                                    \
-  F(MC_SWEEP)                                       \
-  F(MC_SWEEP_CODE)                                  \
-  F(MC_SWEEP_MAP)                                   \
-  F(MC_SWEEP_OLD)                                   \
-  F(MINOR_MC)                                       \
-  F(MINOR_MC_CLEAR)                                 \
-  F(MINOR_MC_CLEAR_STRING_TABLE)                    \
-  F(MINOR_MC_CLEAR_WEAK_LISTS)                      \
-  F(MINOR_MC_EVACUATE)                              \
-  F(MINOR_MC_EVACUATE_CLEAN_UP)                     \
-  F(MINOR_MC_EVACUATE_COPY)                         \
-  F(MINOR_MC_EVACUATE_EPILOGUE)                     \
-  F(MINOR_MC_EVACUATE_PROLOGUE)                     \
-  F(MINOR_MC_EVACUATE_REBALANCE)                    \
-  F(MINOR_MC_EVACUATE_UPDATE_POINTERS)              \
-  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_SLOTS)        \
-  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS) \
-  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_WEAK)         \
-  F(MINOR_MC_MARK)                                  \
-  F(MINOR_MC_MARK_GLOBAL_HANDLES)                   \
-  F(MINOR_MC_MARK_SEED)                             \
-  F(MINOR_MC_MARK_ROOTS)                            \
-  F(MINOR_MC_MARK_WEAK)                             \
-  F(MINOR_MC_MARKING_DEQUE)                         \
-  F(MINOR_MC_RESET_LIVENESS)                        \
-  F(MINOR_MC_SWEEPING)                              \
-  F(SCAVENGER_EVACUATE)                             \
-  F(SCAVENGER_OLD_TO_NEW_POINTERS)                  \
-  F(SCAVENGER_ROOTS)                                \
-  F(SCAVENGER_SCAVENGE)                             \
-  F(SCAVENGER_SEMISPACE)                            \
+#define TRACER_SCOPES(F)                              \
+  INCREMENTAL_SCOPES(F)                               \
+  F(HEAP_EPILOGUE)                                    \
+  F(HEAP_EPILOGUE_REDUCE_NEW_SPACE)                   \
+  F(HEAP_EXTERNAL_EPILOGUE)                           \
+  F(HEAP_EXTERNAL_PROLOGUE)                           \
+  F(HEAP_EXTERNAL_WEAK_GLOBAL_HANDLES)                \
+  F(HEAP_PROLOGUE)                                    \
+  F(MC_CLEAR)                                         \
+  F(MC_CLEAR_DEPENDENT_CODE)                          \
+  F(MC_CLEAR_MAPS)                                    \
+  F(MC_CLEAR_SLOTS_BUFFER)                            \
+  F(MC_CLEAR_STORE_BUFFER)                            \
+  F(MC_CLEAR_STRING_TABLE)                            \
+  F(MC_CLEAR_WEAK_CELLS)                              \
+  F(MC_CLEAR_WEAK_COLLECTIONS)                        \
+  F(MC_CLEAR_WEAK_LISTS)                              \
+  F(MC_EPILOGUE)                                      \
+  F(MC_EVACUATE)                                      \
+  F(MC_EVACUATE_CANDIDATES)                           \
+  F(MC_EVACUATE_CLEAN_UP)                             \
+  F(MC_EVACUATE_COPY)                                 \
+  F(MC_EVACUATE_EPILOGUE)                             \
+  F(MC_EVACUATE_PROLOGUE)                             \
+  F(MC_EVACUATE_REBALANCE)                            \
+  F(MC_EVACUATE_UPDATE_POINTERS)                      \
+  F(MC_EVACUATE_UPDATE_POINTERS_TO_EVACUATED)         \
+  F(MC_EVACUATE_UPDATE_POINTERS_TO_NEW)               \
+  F(MC_EVACUATE_UPDATE_POINTERS_WEAK)                 \
+  F(MC_FINISH)                                        \
+  F(MC_MARK)                                          \
+  F(MC_MARK_FINISH_INCREMENTAL)                       \
+  F(MC_MARK_ROOTS)                                    \
+  F(MC_MARK_WEAK_CLOSURE)                             \
+  F(MC_MARK_WEAK_CLOSURE_EPHEMERAL)                   \
+  F(MC_MARK_WEAK_CLOSURE_WEAK_HANDLES)                \
+  F(MC_MARK_WEAK_CLOSURE_WEAK_ROOTS)                  \
+  F(MC_MARK_WEAK_CLOSURE_HARMONY)                     \
+  F(MC_MARK_WRAPPER_EPILOGUE)                         \
+  F(MC_MARK_WRAPPER_PROLOGUE)                         \
+  F(MC_MARK_WRAPPER_TRACING)                          \
+  F(MC_PROLOGUE)                                      \
+  F(MC_SWEEP)                                         \
+  F(MC_SWEEP_CODE)                                    \
+  F(MC_SWEEP_MAP)                                     \
+  F(MC_SWEEP_OLD)                                     \
+  F(MINOR_MC)                                         \
+  F(MINOR_MC_CLEAR)                                   \
+  F(MINOR_MC_CLEAR_STRING_TABLE)                      \
+  F(MINOR_MC_CLEAR_WEAK_LISTS)                        \
+  F(MINOR_MC_EVACUATE)                                \
+  F(MINOR_MC_EVACUATE_CLEAN_UP)                       \
+  F(MINOR_MC_EVACUATE_COPY)                           \
+  F(MINOR_MC_EVACUATE_EPILOGUE)                       \
+  F(MINOR_MC_EVACUATE_PROLOGUE)                       \
+  F(MINOR_MC_EVACUATE_REBALANCE)                      \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS)                \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW)         \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS)   \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_TOSPACE) \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_OLD)     \
+  F(MINOR_MC_EVACUATE_UPDATE_POINTERS_WEAK)           \
+  F(MINOR_MC_MARK)                                    \
+  F(MINOR_MC_MARK_GLOBAL_HANDLES)                     \
+  F(MINOR_MC_MARK_SEED)                               \
+  F(MINOR_MC_MARK_ROOTS)                              \
+  F(MINOR_MC_MARK_WEAK)                               \
+  F(MINOR_MC_MARKING_DEQUE)                           \
+  F(MINOR_MC_RESET_LIVENESS)                          \
+  F(MINOR_MC_SWEEPING)                                \
+  F(SCAVENGER_EVACUATE)                               \
+  F(SCAVENGER_OLD_TO_NEW_POINTERS)                    \
+  F(SCAVENGER_ROOTS)                                  \
+  F(SCAVENGER_SCAVENGE)                               \
+  F(SCAVENGER_SEMISPACE)                              \
   F(SCAVENGER_WEAK)
 
 #define TRACE_GC(tracer, scope_id)                             \

src/heap/mark-compact.cc

@@ -4235,91 +4235,58 @@ void MarkCompactCollector::Evacuate() {
 #endif
 }
 
-class UpdatingItem : public ItemParallelJob::Item {
- public:
-  virtual ~UpdatingItem() {}
-  virtual void Process() = 0;
-};
-
-class PointersUpatingTask : public ItemParallelJob::Task {
+template <RememberedSetType type>
+class PointerUpdateJobTraits {
  public:
-  explicit PointersUpatingTask(Isolate* isolate)
-      : ItemParallelJob::Task(isolate) {}
-
-  void RunInParallel() override {
-    UpdatingItem* item = nullptr;
-    while ((item = GetItem<UpdatingItem>()) != nullptr) {
-      item->Process();
-      item->MarkFinished();
-    }
-  };
-};
+  typedef int PerPageData;  // Per page data is not used in this job.
+  typedef const MarkCompactCollectorBase* PerTaskData;
 
-class ToSpaceUpdatingItem : public UpdatingItem {
- public:
-  explicit ToSpaceUpdatingItem(MemoryChunk* chunk, Address start, Address end,
-                               MarkingState marking_state)
-      : chunk_(chunk),
-        start_(start),
-        end_(end),
-        marking_state_(marking_state) {}
-  virtual ~ToSpaceUpdatingItem() {}
-
-  void Process() override {
-    if (chunk_->IsFlagSet(Page::PAGE_NEW_NEW_PROMOTION)) {
-      // New->new promoted pages contain garbage so they require iteration using
-      // markbits.
-      ProcessVisitLive();
-    } else {
-      ProcessVisitAll();
-    }
+  static void ProcessPageInParallel(Heap* heap, PerTaskData task_data,
+                                    MemoryChunk* chunk, PerPageData) {
+    base::LockGuard<base::RecursiveMutex> guard(chunk->mutex());
+    UpdateUntypedPointers(heap, chunk, task_data);
+    UpdateTypedPointers(heap, chunk, task_data);
   }
 
  private:
-  void ProcessVisitAll() {
-    PointersUpdatingVisitor visitor;
-    for (Address cur = start_; cur < end_;) {
-      HeapObject* object = HeapObject::FromAddress(cur);
-      Map* map = object->map();
-      int size = object->SizeFromMap(map);
-      object->IterateBody(map->instance_type(), size, &visitor);
-      cur += size;
+  static void UpdateUntypedPointers(Heap* heap, MemoryChunk* chunk,
+                                    const MarkCompactCollectorBase* collector) {
+    if (type == OLD_TO_NEW) {
+      RememberedSet<OLD_TO_NEW>::Iterate(
+          chunk, [heap, collector](Address slot) {
+            return CheckAndUpdateOldToNewSlot(heap, slot, collector);
+          });
+    } else {
+      RememberedSet<OLD_TO_OLD>::Iterate(chunk, [](Address slot) {
+        return UpdateSlot(reinterpret_cast<Object**>(slot));
+      });
     }
   }
 
-  void ProcessVisitLive() {
-    // For young generation evacuations we want to visit grey objects, for
-    // full MC, we need to visit black objects.
-    PointersUpdatingVisitor visitor;
-    LiveObjectIterator<kAllLiveObjects> it(chunk_, marking_state_);
-    HeapObject* object = nullptr;
-    while ((object = it.Next()) != nullptr) {
-      object->IterateBodyFast(&visitor);
+  static void UpdateTypedPointers(Heap* heap, MemoryChunk* chunk,
+                                  const MarkCompactCollectorBase* collector) {
+    if (type == OLD_TO_OLD) {
+      Isolate* isolate = heap->isolate();
+      RememberedSet<OLD_TO_OLD>::IterateTyped(
+          chunk,
+          [isolate](SlotType slot_type, Address host_addr, Address slot) {
+            return UpdateTypedSlotHelper::UpdateTypedSlot(isolate, slot_type,
+                                                          slot, UpdateSlot);
+          });
+    } else {
+      Isolate* isolate = heap->isolate();
+      RememberedSet<OLD_TO_NEW>::IterateTyped(
+          chunk, [isolate, heap, collector](SlotType slot_type,
+                                            Address host_addr, Address slot) {
+            return UpdateTypedSlotHelper::UpdateTypedSlot(
+                isolate, slot_type, slot, [heap, collector](Object** slot) {
+                  return CheckAndUpdateOldToNewSlot(
+                      heap, reinterpret_cast<Address>(slot), collector);
+                });
+          });
     }
   }
 
-  MemoryChunk* chunk_;
-  Address start_;
-  Address end_;
-  MarkingState marking_state_;
-};
-
-template <RememberedSetType type>
-class RememberedSetUpdatingItem : public UpdatingItem {
- public:
-  explicit RememberedSetUpdatingItem(Heap* heap,
-                                     MarkCompactCollectorBase* collector,
-                                     MemoryChunk* chunk)
-      : heap_(heap), collector_(collector), chunk_(chunk) {}
-  virtual ~RememberedSetUpdatingItem() {}
-
-  void Process() override {
-    base::LockGuard<base::RecursiveMutex> guard(chunk_->mutex());
-    UpdateUntypedPointers();
-    UpdateTypedPointers();
-  }
-
- private:
   static SlotCallbackResult CheckAndUpdateOldToNewSlot(
       Heap* heap, Address slot_address,
       const MarkCompactCollectorBase* collector) {
@@ -4356,105 +4323,109 @@ class RememberedSetUpdatingItem : public UpdatingItem {
     }
     return REMOVE_SLOT;
   }
+};
 
-  void UpdateUntypedPointers() {
-    if (type == OLD_TO_NEW) {
-      RememberedSet<OLD_TO_NEW>::Iterate(chunk_, [this](Address slot) {
-        return CheckAndUpdateOldToNewSlot(heap_, slot, collector_);
-      });
+template <RememberedSetType type>
+void MarkCompactCollectorBase::UpdatePointersInParallel(
+    base::Semaphore* semaphore) {
+  PageParallelJob<PointerUpdateJobTraits<type> > job(
+      heap(), heap()->isolate()->cancelable_task_manager(), semaphore);
+  RememberedSet<type>::IterateMemoryChunks(
+      heap(), [&job](MemoryChunk* chunk) { job.AddPage(chunk, 0); });
+  const int num_pages = job.NumberOfPages();
+  if (num_pages == 0) return;
+  const int num_tasks =
+      NumberOfParallelPointerUpdateTasks(num_pages, old_to_new_slots_);
+  job.Run(num_tasks, [this](int i) { return this; });
+}
+
+class ToSpacePointerUpdateJobTraits {
+ public:
+  struct PageData {
+    Address start;
+    Address end;
+    MarkingState marking_state;
+  };
+
+  typedef PageData PerPageData;
+  typedef PointersUpdatingVisitor* PerTaskData;
+
+  static void ProcessPageInParallel(Heap* heap, PerTaskData visitor,
+                                    MemoryChunk* chunk, PerPageData page_data) {
+    if (chunk->IsFlagSet(Page::PAGE_NEW_NEW_PROMOTION)) {
+      // New->new promoted pages contain garbage so they require iteration
+      // using markbits.
+      ProcessPageInParallelVisitLive(heap, visitor, chunk, page_data);
     } else {
-      RememberedSet<OLD_TO_OLD>::Iterate(chunk_, [](Address slot) {
-        return UpdateSlot(reinterpret_cast<Object**>(slot));
-      });
+      ProcessPageInParallelVisitAll(heap, visitor, chunk, page_data);
     }
   }
 
-  void UpdateTypedPointers() {
-    Isolate* isolate = heap_->isolate();
-    if (type == OLD_TO_NEW) {
-      RememberedSet<OLD_TO_NEW>::IterateTyped(
-          chunk_,
-          [isolate, this](SlotType slot_type, Address host_addr, Address slot) {
-            return UpdateTypedSlotHelper::UpdateTypedSlot(
-                isolate, slot_type, slot, [this](Object** slot) {
-                  return CheckAndUpdateOldToNewSlot(
-                      heap_, reinterpret_cast<Address>(slot), collector_);
-                });
-          });
-    } else {
-      RememberedSet<OLD_TO_OLD>::IterateTyped(
-          chunk_,
-          [isolate](SlotType slot_type, Address host_addr, Address slot) {
-            return UpdateTypedSlotHelper::UpdateTypedSlot(isolate, slot_type,
-                                                          slot, UpdateSlot);
-          });
+ private:
+  static void ProcessPageInParallelVisitAll(Heap* heap, PerTaskData visitor,
+                                            MemoryChunk* chunk,
+                                            PerPageData page_data) {
+    for (Address cur = page_data.start; cur < page_data.end;) {
+      HeapObject* object = HeapObject::FromAddress(cur);
+      Map* map = object->map();
+      int size = object->SizeFromMap(map);
+      object->IterateBody(map->instance_type(), size, visitor);
+      cur += size;
     }
   }
 
-  Heap* heap_;
-  MarkCompactCollectorBase* collector_;
-  MemoryChunk* chunk_;
+  static void ProcessPageInParallelVisitLive(Heap* heap, PerTaskData visitor,
+                                             MemoryChunk* chunk,
+                                             PerPageData page_data) {
+    // For young generation evacuations we want to visit grey objects, for
+    // full MC, we need to visit black objects.
+    LiveObjectIterator<kAllLiveObjects> it(chunk, page_data.marking_state);
+    HeapObject* object = NULL;
+    while ((object = it.Next()) != NULL) {
+      Map* map = object->map();
+      int size = object->SizeFromMap(map);
+      object->IterateBody(map->instance_type(), size, visitor);
+    }
+  }
 };
 
-int MarkCompactCollectorBase::CollectToSpaceUpdatingItems(
-    ItemParallelJob* job) {
-  // Seed to space pages.
+void MarkCompactCollectorBase::UpdateToSpacePointersInParallel(
+    base::Semaphore* semaphore) {
+  PageParallelJob<ToSpacePointerUpdateJobTraits> job(
+      heap(), isolate()->cancelable_task_manager(), semaphore);
   const Address space_start = heap()->new_space()->bottom();
   const Address space_end = heap()->new_space()->top();
-  int pages = 0;
   for (Page* page : PageRange(space_start, space_end)) {
     Address start =
         page->Contains(space_start) ? space_start : page->area_start();
     Address end = page->Contains(space_end) ? space_end : page->area_end();
-    job->AddItem(
-        new ToSpaceUpdatingItem(page, start, end, marking_state(page)));
-    pages++;
+    job.AddPage(page, {start, end, marking_state(page)});
   }
-  if (pages == 0) return 0;
-  return NumberOfParallelToSpacePointerUpdateTasks(pages);
-}
-
-template <RememberedSetType type>
-int MarkCompactCollectorBase::CollectRememberedSetUpdatingItems(
-    ItemParallelJob* job) {
-  int pages = 0;
-  RememberedSet<type>::IterateMemoryChunks(
-      heap(), [this, &job, &pages](MemoryChunk* chunk) {
-        job->AddItem(new RememberedSetUpdatingItem<type>(heap(), this, chunk));
-        pages++;
-      });
-  if (pages == 0) return 0;
-  return NumberOfParallelPointerUpdateTasks(
-      pages, type == OLD_TO_NEW ? old_to_new_slots_ : -1);
+  PointersUpdatingVisitor visitor;
+  const int num_tasks =
+      NumberOfParallelToSpacePointerUpdateTasks(job.NumberOfPages());
+  job.Run(num_tasks, [&visitor](int i) { return &visitor; });
 }
 
 void MarkCompactCollector::UpdatePointersAfterEvacuation() {
   TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS);
 
-  PointersUpdatingVisitor updating_visitor;
-  ItemParallelJob updating_job(isolate()->cancelable_task_manager(),
-                               &page_parallel_job_semaphore_);
-
-  const int to_space_tasks = CollectToSpaceUpdatingItems(&updating_job);
-  const int remembered_set_tasks_old_new =
-      CollectRememberedSetUpdatingItems<OLD_TO_NEW>(&updating_job);
-  const int remembered_set_tasks_old_old =
-      CollectRememberedSetUpdatingItems<OLD_TO_OLD>(&updating_job);
-  const int num_tasks = Max(to_space_tasks, Max(remembered_set_tasks_old_new,
-                                                remembered_set_tasks_old_old));
-  for (int i = 0; i < num_tasks; i++) {
-    updating_job.AddTask(new PointersUpatingTask(isolate()));
-  }
 
   {
     TRACE_GC(heap()->tracer(),
-             GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS);
+             GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW);
+    UpdateToSpacePointersInParallel(&page_parallel_job_semaphore_);
+    // Update roots.
+    PointersUpdatingVisitor updating_visitor;
     heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_SWEEP_NEWSPACE);
+    UpdatePointersInParallel<OLD_TO_NEW>(&page_parallel_job_semaphore_);
   }
+
   {
-    TRACE_GC(heap()->tracer(),
-             GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_SLOTS);
-    updating_job.Run();
+    Heap* heap = this->heap();
+    TRACE_GC(heap->tracer(),
+             GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_TO_EVACUATED);
+    UpdatePointersInParallel<OLD_TO_OLD>(&page_parallel_job_semaphore_);
   }
 
   {
@@ -4474,26 +4445,26 @@ void MinorMarkCompactCollector::UpdatePointersAfterEvacuation() {
            GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS);
 
   PointersUpdatingVisitor updating_visitor;
-  ItemParallelJob updating_job(isolate()->cancelable_task_manager(),
-                               &page_parallel_job_semaphore_);
-
-  const int to_space_tasks = CollectToSpaceUpdatingItems(&updating_job);
-  const int remembered_set_tasks =
-      CollectRememberedSetUpdatingItems<OLD_TO_NEW>(&updating_job);
-  const int num_tasks = Max(to_space_tasks, remembered_set_tasks);
-  for (int i = 0; i < num_tasks; i++) {
-    updating_job.AddTask(new PointersUpatingTask(isolate()));
-  }
 
   {
     TRACE_GC(heap()->tracer(),
-             GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS);
-    heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_MINOR_MC_UPDATE);
-  }
-  {
-    TRACE_GC(heap()->tracer(),
-             GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_SLOTS);
-    updating_job.Run();
+             GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW);
+    {
+      TRACE_GC(
+          heap()->tracer(),
+          GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_TOSPACE);
+      UpdateToSpacePointersInParallel(&page_parallel_job_semaphore_);
+    }
+    {
+      TRACE_GC(heap()->tracer(),
+               GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS);
+      heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_MINOR_MC_UPDATE);
+    }
+    {
+      TRACE_GC(heap()->tracer(),
+               GCTracer::Scope::MINOR_MC_EVACUATE_UPDATE_POINTERS_TO_NEW_OLD);
+      UpdatePointersInParallel<OLD_TO_NEW>(&page_parallel_job_semaphore_);
+    }
   }
 
   {

src/heap/mark-compact.h

@@ -22,7 +22,6 @@ namespace internal {
 // Forward declarations.
 class EvacuationJobTraits;
 class HeapObjectVisitor;
-class ItemParallelJob;
 class LocalWorkStealingMarkingDeque;
 class MarkCompactCollector;
 class MinorMarkCompactCollector;
@@ -277,9 +276,9 @@ class MarkCompactCollectorBase {
   // Returns whether this page should be moved according to heuristics.
   bool ShouldMovePage(Page* p, intptr_t live_bytes);
 
-  int CollectToSpaceUpdatingItems(ItemParallelJob* job);
   template <RememberedSetType type>
-  int CollectRememberedSetUpdatingItems(ItemParallelJob* job);
+  void UpdatePointersInParallel(base::Semaphore* semaphore);
+  void UpdateToSpacePointersInParallel(base::Semaphore* semaphore);
 
   int NumberOfParallelCompactionTasks(int pages);
   int NumberOfParallelPointerUpdateTasks(int pages, int slots);