[heap] Do not wait for marking deque uncommit task on tear down.

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 2101 matching lines @@
 
 void MarkingDeque::SetUp() {
   backing_store_ = new base::VirtualMemory(kMaxSize);
   backing_store_committed_size_ = 0;
   if (backing_store_ == nullptr) {
     V8::FatalProcessOutOfMemory("MarkingDeque::SetUp");
   }
 }
 
 void MarkingDeque::TearDown() {
-  CancelOrWaitForUncommitTask();
   delete backing_store_;
 }
 
 void MarkingDeque::StartUsing() {
   base::LockGuard<base::Mutex> guard(&mutex_);
   if (in_use_) {
     // This can happen in mark-compact GC if the incremental marker already
     // started using the marking deque.
     return;
   }
@@ skipping 47 matching lines @@
       break;
     }
   }
   if (backing_store_committed_size_ == 0) {
     V8::FatalProcessOutOfMemory("MarkingDeque::EnsureCommitted");
   }
 }
 
 void MarkingDeque::StartUncommitTask() {
   if (!uncommit_task_pending_) {
+    uncommit_task_pending_ = true;
     UncommitTask* task = new UncommitTask(heap_->isolate(), this);
-    uncommit_task_id_ = task->id();
-    uncommit_task_pending_ = true;
     V8::GetCurrentPlatform()->CallOnBackgroundThread(
         task, v8::Platform::kShortRunningTask);
   }
 }
 
-void MarkingDeque::CancelOrWaitForUncommitTask() {
-  base::LockGuard<base::Mutex> guard(&mutex_);
-  if (!uncommit_task_pending_ ||
-      heap_->isolate()->cancelable_task_manager()->TryAbort(
-          uncommit_task_id_) != CancelableTaskManager::kTaskRunning) {
-    return;
-  }
-  while (uncommit_task_pending_) {
-    uncommit_task_barrier_.Wait(&mutex_);
-  }
-}
-
 class MarkCompactCollector::ObjectStatsVisitor
     : public MarkCompactCollector::HeapObjectVisitor {
  public:
   ObjectStatsVisitor(Heap* heap, ObjectStats* live_stats,
                      ObjectStats* dead_stats)
       : live_collector_(heap, live_stats), dead_collector_(heap, dead_stats) {
     DCHECK_NOT_NULL(live_stats);
     DCHECK_NOT_NULL(dead_stats);
     // Global objects are roots and thus recorded as live.
     live_collector_.CollectGlobalStatistics();
@@ skipping 1706 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8