Unlink evacuation candidates from list of pages before starting sweeper threads.

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 542 matching lines @@
 void MarkCompactCollector::WaitUntilSweepingCompleted() {
   ASSERT(sweeping_pending_ == true);
   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()->paged_space(OLD_DATA_SPACE)->ResetUnsweptFreeBytes();
   heap()->paged_space(OLD_POINTER_SPACE)->ResetUnsweptFreeBytes();
+  heap()->FreeQueuedChunks();

[Michael Starzinger, 2013/03/08 12:52:06]

There shouldn't be any queued chunks at this point, I think this call is
obsolete.

[Hannes Payer (out of office), 2013/03/08 14:02:30]

Done.

 }
 
 
 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);
   }
   space->AddToAccountingStats(freed_bytes);
   space->DecrementUnsweptFreeBytes(freed_bytes);
   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 (IsConcurrentSweepingInProgress()) {
     // 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 1917 matching lines @@
       if (static_cast<PagedSpace*>(p->owner())->CanExpand()) {
         EvacuateLiveObjectsFromPage(p);
       } else {
         // Without room for expansion evacuation is not guaranteed to succeed.
         // Pessimistically abandon unevacuated pages.
         for (int j = i; j < npages; j++) {
           Page* page = evacuation_candidates_[j];
           slots_buffer_allocator_.DeallocateChain(page->slots_buffer_address());
           page->ClearEvacuationCandidate();
           page->SetFlag(Page::RESCAN_ON_EVACUATION);
+          page->InsertAfter(static_cast<PagedSpace*>(page->owner())->anchor());
         }
         return;
       }
     }
   }
 }
 
 
 class EvacuationWeakObjectRetainer : public WeakObjectRetainer {
  public:
@@ skipping 457 matching lines @@
     p->set_scan_on_scavenge(false);
     slots_buffer_allocator_.DeallocateChain(p->slots_buffer_address());
     p->ResetLiveBytes();
     space->ReleasePage(p);
   }
   evacuation_candidates_.Rewind(0);
   compacting_ = false;
 }
 
 
+void MarkCompactCollector::UnlinkEvacuationCandidates() {

[Michael Starzinger, 2013/03/08 12:52:06]

Can we move that to above the ReleaseEvacuationCandidates because that's the
natural order in which it gets called.

[Hannes Payer (out of office), 2013/03/08 14:02:30]

Done.

+  int npages = evacuation_candidates_.length();
+  for (int i = 0; i < npages; i++) {
+    Page* p = evacuation_candidates_[i];
+    if (!p->IsEvacuationCandidate()) continue;
+    p->Unlink();
+    p->ClearSweptPrecisely();
+    p->ClearSweptConservatively();
+  }
+}
+
+
 static const int kStartTableEntriesPerLine = 5;
 static const int kStartTableLines = 171;
 static const int kStartTableInvalidLine = 127;
 static const int kStartTableUnusedEntry = 126;
 
 #define _ kStartTableUnusedEntry
 #define X kStartTableInvalidLine
 // Mark-bit to object start offset table.
 //
 // The line is indexed by the mark bits in a byte.  The first number on
@@ skipping 553 matching lines @@
   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.
   SequentialSweepingScope scope(this);
   SweepSpace(heap()->old_pointer_space(), how_to_sweep);
   SweepSpace(heap()->old_data_space(), how_to_sweep);
 
+  UnlinkEvacuationCandidates();

[Michael Starzinger, 2013/03/08 12:52:06]

Add a short comment about why this needs to be done before the sweeper threads
start.

[Hannes Payer (out of office), 2013/03/08 14:02:30]

Done.

+
   if (how_to_sweep == PARALLEL_CONSERVATIVE ||
       how_to_sweep == CONCURRENT_CONSERVATIVE) {
     // TODO(hpayer): fix race with concurrent sweeper
     StartSweeperThreads();
   }
 
   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();
-  }
+  ReleaseEvacuationCandidates();

[Michael Starzinger, 2013/03/08 12:52:06]

The right place to call FreeQueuedChunks would be after we release evacuation
candidates, it might even make sense to move it into
ReleaseEvacuationCandidates().

[Hannes Payer (out of office), 2013/03/08 14:02:30]

Done.

 }
 
 
 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