[heap] Properly account for wasted bytes.

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/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 3535 matching lines @@
 enum FreeSpaceTreatmentMode { IGNORE_FREE_SPACE, ZAP_FREE_SPACE };
 
 
 template <MarkCompactCollector::SweepingParallelism mode>
 static intptr_t Free(PagedSpace* space, FreeList* free_list, Address start,
                      int size) {
   if (mode == MarkCompactCollector::SWEEP_ON_MAIN_THREAD) {
     DCHECK(free_list == NULL);
     return space->Free(start, size);
   } else {
-    // TODO(hpayer): account for wasted bytes in concurrent sweeping too.
     return size - free_list->Free(start, size);
   }
 }
 
 
 // Sweeps a page. After sweeping the page can be iterated.
 // Slots in live objects pointing into evacuation candidates are updated
 // if requested.
 // Returns the size of the biggest continuous freed memory chunk in bytes.
 template <SweepingMode sweeping_mode,
@@ skipping 1033 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(&rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8