Parallel and concurrent sweeping.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 401f4f7948adc09cb845390ef7f37036fa179aee..e7a9fdc8ce9cfe8eb8c7cd2f2aac19702f7693fb 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -563,6 +563,54 @@ void Heap::CollectAllGarbage(int flags, const char* gc_reason) {
 }
 
 
+void Heap::StartParallelSweeping(SweeperType sweeper_type) {
+  SweeperThread::set_sweeping_pending(true);
+  for (int i = 0; i < FLAG_sweeper_threads; i++) {
+    isolate()->sweeper_threads()[i]->StartSweeping(sweeper_type);
+  }
+}
+
+
+void Heap::WaitUntilParallelSweepingCompleted() {
+  for (int i = 0; i < FLAG_sweeper_threads; i++) {
+    isolate()->sweeper_threads()[i]->WaitForSweeperThread();
+  }
+  SweeperThread::set_sweeping_pending(false);
+  FinalizeParallelSweeping();
+}
+
+
+void Heap::StealMemoryFromSweeperThreads(PagedSpace* space) {
+  for (int i = 0; i < FLAG_sweeper_threads; i++) {
+    isolate()->sweeper_threads()[i]->StealMemory(space);
+  }
+}
+
+
+void Heap::FinalizeParallelSweeping() {
+  StealMemoryFromSweeperThreads(paged_space(OLD_DATA_SPACE));
+  StealMemoryFromSweeperThreads(paged_space(OLD_POINTER_SPACE));
+  FreeQueuedChunks();
+}
+
+
+bool Heap::IsConcurrentSweepingPending() {
+  return SweeperThread::sweeping_pending();
+}
+
+
+bool Heap::IsConcurrentSweepingActivated() {
+  return isolate()->sweeper_threads() != NULL &&
+         FLAG_concurrent_sweeping;
+}
+
+
+bool Heap::AreSweepingThreadsActivated() {
+  return isolate()->sweeper_threads() != NULL &&
+         (FLAG_concurrent_sweeping || FLAG_parallel_sweeping);
+}
+
+
 void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
@@ -1273,7 +1321,12 @@ void Heap::Scavenge() {
 
   incremental_marking()->PrepareForScavenge();
 
-  AdvanceSweepers(static_cast<int>(new_space_.Size()));
+  if (AreSweepingThreadsActivated()) {
+    StealMemoryFromSweeperThreads(paged_space(OLD_DATA_SPACE));
+    StealMemoryFromSweeperThreads(paged_space(OLD_POINTER_SPACE));
+  } else {
+    AdvanceSweepers(static_cast<int>(new_space_.Size()));
+  }
 
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.