doubly-linked free-lists for thread caches and page heaps

third_party/tcmalloc/chromium/src/common.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 88 matching lines @@
   }
   if (ClassIndex(kMaxSize) >= sizeof(class_array_)) {
     CRASH("Invalid class index %d for kMaxSize\n", ClassIndex(kMaxSize));
   }
 
   // Compute the size classes we want to use
   int sc = 1;   // Next size class to assign
   int alignment = kAlignment;
   CHECK_CONDITION(kAlignment <= 16);
   int last_lg = -1;
-  for (size_t size = kAlignment; size <= kMaxSize; size += alignment) {
+  for (size_t size = kMinClassSize; size <= kMaxSize; size += alignment) {
     int lg = LgFloor(size);
     if (lg > last_lg) {
       // Increase alignment every so often to reduce number of size classes.
       alignment = AlignmentForSize(size);
       last_lg = lg;
     }
     CHECK_CONDITION((size % alignment) == 0);
 
     // Allocate enough pages so leftover is less than 1/8 of total.
     // This bounds wasted space to at most 12.5%.
@@ skipping 88 matching lines @@
   return result;
 }
 
 uint64_t metadata_system_bytes() { return metadata_system_bytes_; }
 
 void increment_metadata_system_bytes(size_t bytes) {
   metadata_system_bytes_ += bytes;
 }
 
 }  // namespace tcmalloc