Release evacuation candidates after parallel sweeper threads completed.

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 525 matching lines @@
 
 
 void MarkCompactCollector::WaitUntilSweepingCompleted() {
   if (sweeping_pending_) {
     for (int i = 0; i < FLAG_sweeper_threads; i++) {
       heap()->isolate()->sweeper_threads()[i]->WaitForSweeperThread();
     }
     sweeping_pending_ = false;
     StealMemoryFromSweeperThreads(heap()->paged_space(OLD_DATA_SPACE));
     StealMemoryFromSweeperThreads(heap()->paged_space(OLD_POINTER_SPACE));
-    heap()->FreeQueuedChunks();
   }
 }
 
 
 intptr_t MarkCompactCollector::
              StealMemoryFromSweeperThreads(PagedSpace* space) {
   intptr_t freed_bytes = 0;
   for (int i = 0; i < FLAG_sweeper_threads; i++) {
     freed_bytes += heap()->isolate()->sweeper_threads()[i]->StealMemory(space);
   }
   return freed_bytes;
 }
 
 
 bool MarkCompactCollector::AreSweeperThreadsActivated() {
   return heap()->isolate()->sweeper_threads() != NULL;
 }
 
 
 bool MarkCompactCollector::IsConcurrentSweepingInProgress() {
   return sweeping_pending_;
 }
 
 
+void MarkCompactCollector::FinalizeSweeping() {
+  ASSERT(sweeping_pending_ == false);
+  ReleaseEvacuationCandidates();
+  heap()->FreeQueuedChunks();
+}
+
+
 void MarkCompactCollector::MarkInParallel() {
   for (int i = 0; i < FLAG_marking_threads; i++) {
     heap()->isolate()->marking_threads()[i]->StartMarking();
   }
 }
 
 
 void MarkCompactCollector::WaitUntilMarkingCompleted() {
   for (int i = 0; i < FLAG_marking_threads; i++) {
     heap()->isolate()->marking_threads()[i]->WaitForMarkingThread();
@@ skipping 299 matching lines @@
 #ifdef DEBUG
   ASSERT(state_ == IDLE);
   state_ = PREPARE_GC;
 #endif
 
   ASSERT(!FLAG_never_compact || !FLAG_always_compact);
 
   if (AreSweeperThreadsActivated() && FLAG_concurrent_sweeping) {
     // Instead of waiting we could also abort the sweeper threads here.
     WaitUntilSweepingCompleted();
+    FinalizeSweeping();
   }
 
   // Clear marking bits if incremental marking is aborted.
   if (was_marked_incrementally_ && abort_incremental_marking_) {
     heap()->incremental_marking()->Abort();
     ClearMarkbits();
     AbortCompaction();
     was_marked_incrementally_ = false;
   }
 
@@ skipping 2373 matching lines @@
   heap_->isolate()->inner_pointer_to_code_cache()->Flush();
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     VerifyEvacuation(heap_);
   }
 #endif
 
   slots_buffer_allocator_.DeallocateChain(&migration_slots_buffer_);
   ASSERT(migration_slots_buffer_ == NULL);
+}
+
+
+void MarkCompactCollector::ReleaseEvacuationCandidates() {
+  int npages = evacuation_candidates_.length();
   for (int i = 0; i < npages; i++) {
     Page* p = evacuation_candidates_[i];
     if (!p->IsEvacuationCandidate()) continue;
     PagedSpace* space = static_cast<PagedSpace*>(p->owner());
     space->Free(p->area_start(), p->area_size());
     p->set_scan_on_scavenge(false);
     slots_buffer_allocator_.DeallocateChain(p->slots_buffer_address());
     p->ResetLiveBytes();
     space->ReleasePage(p);
   }
@@ skipping 424 matching lines @@
       SweepConservatively<SWEEP_IN_PARALLEL>(space, private_free_list, p);
       free_list->Concatenate(private_free_list);
     }
   }
 }
 
 
 void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
   space->set_was_swept_conservatively(sweeper == CONSERVATIVE ||
                                       sweeper == LAZY_CONSERVATIVE ||
-                                      sweeper == PARALLEL_CONSERVATIVE);
+                                      sweeper == PARALLEL_CONSERVATIVE ||
+                                      sweeper == CONCURRENT_CONSERVATIVE);
   space->ClearStats();
 
   PageIterator it(space);
 
   intptr_t freed_bytes = 0;
   int pages_swept = 0;
   bool lazy_sweeping_active = false;
   bool unused_page_present = false;
 
   while (it.has_next()) {
@@ skipping 53 matching lines @@
         if (FLAG_gc_verbose) {
           PrintF("Sweeping 0x%" V8PRIxPTR " conservatively as needed.\n",
                  reinterpret_cast<intptr_t>(p));
         }
         freed_bytes += SweepConservatively<SWEEP_SEQUENTIALLY>(space, NULL, p);
         pages_swept++;
         space->SetPagesToSweep(p->next_page());
         lazy_sweeping_active = true;
         break;
       }
+      case CONCURRENT_CONSERVATIVE:
       case PARALLEL_CONSERVATIVE: {
         if (FLAG_gc_verbose) {
           PrintF("Sweeping 0x%" V8PRIxPTR " conservatively in parallel.\n",
                  reinterpret_cast<intptr_t>(p));
         }
         p->set_parallel_sweeping(1);
         break;
       }
       case PRECISE: {
         if (FLAG_gc_verbose) {
@@ skipping 25 matching lines @@
 }
 
 
 void MarkCompactCollector::SweepSpaces() {
   GCTracer::Scope gc_scope(tracer_, GCTracer::Scope::MC_SWEEP);
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
   SweeperType how_to_sweep =
       FLAG_lazy_sweeping ? LAZY_CONSERVATIVE : CONSERVATIVE;
-  if (AreSweeperThreadsActivated()) how_to_sweep = PARALLEL_CONSERVATIVE;
+  if (FLAG_parallel_sweeping) how_to_sweep = PARALLEL_CONSERVATIVE;
+  if (FLAG_concurrent_sweeping) how_to_sweep = CONCURRENT_CONSERVATIVE;
   if (FLAG_expose_gc) how_to_sweep = CONSERVATIVE;
   if (sweep_precisely_) how_to_sweep = PRECISE;
   // Noncompacting collections simply sweep the spaces to clear the mark
   // bits and free the nonlive blocks (for old and map spaces).  We sweep
   // the map space last because freeing non-live maps overwrites them and
   // the other spaces rely on possibly non-live maps to get the sizes for
   // non-live objects.
 
   SweepSpace(heap()->old_pointer_space(), how_to_sweep);
   SweepSpace(heap()->old_data_space(), how_to_sweep);
 
-  if (how_to_sweep == PARALLEL_CONSERVATIVE) {
+  if (how_to_sweep == PARALLEL_CONSERVATIVE ||
+      how_to_sweep == CONCURRENT_CONSERVATIVE) {
     // TODO(hpayer): fix race with concurrent sweeper
     StartSweeperThreads();
-    if (FLAG_parallel_sweeping && !FLAG_concurrent_sweeping) {
-      WaitUntilSweepingCompleted();
-    }
+  }
+
+  if (how_to_sweep == PARALLEL_CONSERVATIVE) {
+    WaitUntilSweepingCompleted();
   }
 
   RemoveDeadInvalidatedCode();
   SweepSpace(heap()->code_space(), PRECISE);
 
   SweepSpace(heap()->cell_space(), PRECISE);
 
   EvacuateNewSpaceAndCandidates();
 
   // ClearNonLiveTransitions depends on precise sweeping of map space to
   // detect whether unmarked map became dead in this collection or in one
   // of the previous ones.
   SweepSpace(heap()->map_space(), PRECISE);
 
   // Deallocate unmarked objects and clear marked bits for marked objects.
   heap_->lo_space()->FreeUnmarkedObjects();
+
+  if (how_to_sweep != CONCURRENT_CONSERVATIVE) {
+    FinalizeSweeping();
+  }
 }
 
 
 void MarkCompactCollector::EnableCodeFlushing(bool enable) {
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (heap()->isolate()->debug()->IsLoaded() ||
       heap()->isolate()->debug()->has_break_points()) {
     enable = false;
   }
 #endif
@@ skipping 180 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal