Parallel and concurrent sweeping.

src/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
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@@ skipping 1064 matching lines @@
                       GarbageCollector collector,
                       const char* gc_reason,
                       const char* collector_reason);
 
   // Performs garbage collection operation.
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   inline bool CollectGarbage(AllocationSpace space,
                              const char* gc_reason = NULL);
 
+  void StartParallelSweeping(SweeperType sweeper_type);
+  void WaitUntilParallelSweepingCompleted();
+  void StealMemoryFromSweeperThreads(PagedSpace* space);
+  void FinalizeParallelSweeping();
+  bool IsConcurrentSweepingActivated();
+  bool AreSweepingThreadsActivated();
+  bool IsConcurrentSweepingPending();

[Michael Starzinger, 2013/01/24 17:15:54]

We should try to move most of that functionality into MarkCompact and minimize
the entry points in Heap. IMHO parallel sweeping should be considered a
subsystem of MarkCompact.

[Hannes Payer (out of office), 2013/01/25 10:46:49]

Done.

+
   static const int kNoGCFlags = 0;
   static const int kSweepPreciselyMask = 1;
   static const int kReduceMemoryFootprintMask = 2;
   static const int kAbortIncrementalMarkingMask = 4;
 
   // Making the heap iterable requires us to sweep precisely and abort any
   // incremental marking as well.
   static const int kMakeHeapIterableMask =
       kSweepPreciselyMask | kAbortIncrementalMarkingMask;
 
@@ skipping 465 matching lines @@
 
   IncrementalMarking* incremental_marking() {
     return &incremental_marking_;
   }
 
   bool IsSweepingComplete() {
     return old_data_space()->IsSweepingComplete() &&
            old_pointer_space()->IsSweepingComplete();
   }
 
+  void SweepInParallel(PagedSpace* paged_space,

[Michael Starzinger, 2013/01/24 17:15:54]

This dispatcher should not be necessary.

[Hannes Payer (out of office), 2013/01/25 10:46:49]

Done.

+                       SweeperType sweeper_type,
+                       FreeList* private_free_list,
+                       FreeList* free_list) {
+    mark_compact_collector()->SweepInParallel(paged_space,
+                                              sweeper_type,
+                                              private_free_list,
+                                              free_list);
+  }
+
   bool AdvanceSweepers(int step_size) {

[Michael Starzinger, 2013/01/24 17:15:54]

This is still being called from the idle notification. For both modes it should
be a NOP.

[Hannes Payer (out of office), 2013/01/25 10:46:49]

Done.

+    ASSERT(!FLAG_parallel_sweeping && !FLAG_concurrent_sweeping);
     bool sweeping_complete = old_data_space()->AdvanceSweeper(step_size);
     sweeping_complete &= old_pointer_space()->AdvanceSweeper(step_size);
     return sweeping_complete;
   }
 
   ExternalStringTable* external_string_table() {
     return &external_string_table_;
   }
 
   // Returns the current sweep generation.
@@ skipping 1260 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_