Remove support for parallel sweeping

src/heap/mark-compact.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 4149 matching lines @@
         // counter to be accurate for unswept pages.
         space->IncreaseUnsweptFreeBytes(p);
         space->ReleasePage(p);
         continue;
       }
       unused_page_present = true;
     }
 
     switch (sweeper) {
       case CONCURRENT_SWEEPING:
-      case PARALLEL_SWEEPING:
         if (!parallel_sweeping_active) {
           if (FLAG_gc_verbose) {
             PrintF("Sweeping 0x%" V8PRIxPTR ".\n",
                    reinterpret_cast<intptr_t>(p));
           }
           Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST,
                 IGNORE_FREE_SPACE>(space, NULL, p, NULL);
           pages_swept++;
           parallel_sweeping_active = true;
         } else {
@@ skipping 30 matching lines @@
   if (FLAG_gc_verbose) {
     PrintF("SweepSpace: %s (%d pages swept)\n",
            AllocationSpaceName(space->identity()), pages_swept);
   }
 
   // Give pages that are queued to be freed back to the OS.
   heap()->FreeQueuedChunks();
 }
 
 
-static bool ShouldStartSweeperThreads(MarkCompactCollector::SweeperType type) {
-  return (type == MarkCompactCollector::PARALLEL_SWEEPING ||
-          type == MarkCompactCollector::CONCURRENT_SWEEPING) &&
-         !FLAG_predictable;
-}
-
-
-static bool ShouldWaitForSweeperThreads(
-    MarkCompactCollector::SweeperType type) {
-  return type == MarkCompactCollector::PARALLEL_SWEEPING;
-}
-
-
 void MarkCompactCollector::SweepSpaces() {
   GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_SWEEP);
   double start_time = 0.0;
   if (FLAG_print_cumulative_gc_stat) {
     start_time = base::OS::TimeCurrentMillis();
   }
 
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
-  SweeperType how_to_sweep = CONCURRENT_SWEEPING;
-  if (FLAG_parallel_sweeping) how_to_sweep = PARALLEL_SWEEPING;
-  if (FLAG_concurrent_sweeping) how_to_sweep = CONCURRENT_SWEEPING;
-
   MoveEvacuationCandidatesToEndOfPagesList();
 
   // 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.
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_OLDSPACE);
     {
       SequentialSweepingScope scope(this);
-      SweepSpace(heap()->old_pointer_space(), how_to_sweep);
-      SweepSpace(heap()->old_data_space(), how_to_sweep);
+      SweepSpace(heap()->old_pointer_space(), CONCURRENT_SWEEPING);
+      SweepSpace(heap()->old_data_space(), CONCURRENT_SWEEPING);
     }
 
-    if (ShouldStartSweeperThreads(how_to_sweep)) {
+    if (!FLAG_predictable) {
       StartSweeperThreads();
     }
-
-    if (ShouldWaitForSweeperThreads(how_to_sweep)) {
-      EnsureSweepingCompleted();
-    }
   }
   RemoveDeadInvalidatedCode();
 
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_CODE);
     SweepSpace(heap()->code_space(), SEQUENTIAL_SWEEPING);
   }
 
   {
@@ skipping 246 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal