[heap] Extend mutex guards for CodeRange.

src/heap/spaces.h

 // Copyright 2011 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_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
@@ skipping 995 matching lines @@
     FreeBlock(void* start_arg, size_t size_arg)
         : start(static_cast<Address>(start_arg)), size(size_arg) {
       DCHECK(IsAddressAligned(start, MemoryChunk::kAlignment));
       DCHECK(size >= static_cast<size_t>(Page::kPageSize));
     }
 
     Address start;
     size_t size;
   };
 
-  // All access to free_list_ require to take the free_list_mutex_. GC threads
-  // may access the free_list_ concurrently to the main thread.
-  base::Mutex free_list_mutex_;
+  // The global mutex guards free_list_ and allocation_list_ as GC threads may
+  // access both lists concurrently to the main thread.
+  base::Mutex code_range_mutex_;
 
   // Freed blocks of memory are added to the free list.  When the allocation
   // list is exhausted, the free list is sorted and merged to make the new
   // allocation list.
   List<FreeBlock> free_list_;
 
   // Memory is allocated from the free blocks on the allocation list.
   // The block at current_allocation_block_index_ is the current block.
   List<FreeBlock> allocation_list_;
   int current_allocation_block_index_;
@@ skipping 1892 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_SPACES_H_