Revert 41938 - Merged third_party/tcmalloc/vendor/src(googleperftools r87) in...

third_party/tcmalloc/chromium/src/thread_cache.cc

 // Copyright (c) 2008, Google Inc.
 // 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
@@ skipping 281 matching lines @@
     next_memory_steal_ = next_memory_steal_->next_;
     return;
   }
 }
 
 int ThreadCache::GetSamplePeriod() {
   return sampler_.GetSamplePeriod();
 }
 
 void ThreadCache::InitModule() {
+  // There is a slight potential race here because of double-checked
+  // locking idiom.  However, as long as the program does a small
+  // allocation before switching to multi-threaded mode, we will be
+  // fine.  We increase the chances of doing such a small allocation
+  // by doing one in the constructor of the module_enter_exit_hook
+  // object declared below.
   SpinLockHolder h(Static::pageheap_lock());
   if (!phinited) {
     Static::InitStaticVars();
     threadcache_allocator.Init();
     phinited = 1;
   }
 }
 
 void ThreadCache::InitTSD() {
   ASSERT(!tsd_inited_);
@@ skipping 186 matching lines @@
 void ThreadCache::set_overall_thread_cache_size(size_t new_size) {
   // Clip the value to a reasonable range
   if (new_size < kMinThreadCacheSize) new_size = kMinThreadCacheSize;
   if (new_size > (1<<30)) new_size = (1<<30);     // Limit to 1GB
   overall_thread_cache_size_ = new_size;
 
   RecomputePerThreadCacheSize();
 }
 
 }  // namespace tcmalloc