Remove sequential sweeping mode and perform lazy sweeping when no sweeper threads are active.

src/mark-compact.h

 // 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.
 
 #ifndef V8_MARK_COMPACT_H_
 #define V8_MARK_COMPACT_H_
 
 #include "src/compiler-intrinsics.h"
 #include "src/spaces.h"
 
@@ skipping 552 matching lines @@
   static inline bool IsMarked(Object* obj);
 
   inline Heap* heap() const { return heap_; }
   inline Isolate* isolate() const;
 
   CodeFlusher* code_flusher() { return code_flusher_; }
   inline bool is_code_flushing_enabled() const { return code_flusher_ != NULL; }
   void EnableCodeFlushing(bool enable);
 
   enum SweeperType {
-    CONSERVATIVE,
     PARALLEL_CONSERVATIVE,
     CONCURRENT_CONSERVATIVE,
     PRECISE
   };
 
   enum SweepingParallelism {
     SWEEP_ON_MAIN_THREAD,
     SWEEP_IN_PARALLEL
   };
 
@@ skipping 74 matching lines @@
   bool is_compacting() const { return compacting_; }
 
   MarkingParity marking_parity() { return marking_parity_; }
 
   // Concurrent and parallel sweeping support. If required_freed_bytes was set
   // to a value larger than 0, then sweeping returns after a block of at least
   // required_freed_bytes was freed. If required_freed_bytes was set to zero
   // then the whole given space is swept.
   int SweepInParallel(PagedSpace* space, int required_freed_bytes);
 
-  void WaitUntilSweepingCompleted();
+  void EnsureSweepingCompleted();
 
+  // If sweeper threads are not active this method will return true. If
+  // this is a latency issue we should be smarter here. Otherwise, it will
+  // return true if the sweeper threads are done processing the pages.
   bool IsSweepingCompleted();
 
   void RefillFreeList(PagedSpace* space);
 
   bool AreSweeperThreadsActivated();
 
-  // If a paged space is passed in, this method checks if the given space is
-  // swept concurrently. Otherwise, this method checks if concurrent sweeping
-  // is in progress right now on any space.
-  bool IsConcurrentSweepingInProgress(PagedSpace* space = NULL);
+  // Checks if sweeping is in progress right now on any space.
+  bool sweeping_in_progress() { return sweeping_in_progress_; }
 
   void set_sequential_sweeping(bool sequential_sweeping) {
     sequential_sweeping_ = sequential_sweeping;
   }
 
   bool sequential_sweeping() const {
     return sequential_sweeping_;
   }
 
   // Mark the global table which maps weak objects to dependent code without
@@ skipping 42 matching lines @@
 
   MarkingParity marking_parity_;
 
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;
 
   bool was_marked_incrementally_;
 
   // True if concurrent or parallel sweeping is currently in progress.
-  bool sweeping_pending_;
+  bool sweeping_in_progress_;
 
   base::Semaphore pending_sweeper_jobs_semaphore_;
 
   bool sequential_sweeping_;
 
   // A pointer to the current stack-allocated GC tracer object during a full
   // collection (NULL before and after).
   GCTracer* tracer_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
@@ skipping 232 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_