Implement committed physical memory stats for Linux.

src/platform-linux.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 683 matching lines @@
               kMmapFd,
               kMmapFdOffset) != MAP_FAILED;
 }
 
 
 bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
   return munmap(base, size) == 0;
 }
 
 
+bool VirtualMemory::HasLazyCommits() {
+  return true;
+}
+
+
 class Thread::PlatformData : public Malloced {
  public:
   PlatformData() : thread_(kNoThread) {}
 
   pthread_t thread_;  // Thread handle for pthread.
 };
 
 Thread::Thread(const Options& options)
     : data_(new PlatformData()),
       stack_size_(options.stack_size()) {
@@ skipping 573 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal