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

third_party/tcmalloc/chromium/src/common.cc

Index: third_party/tcmalloc/chromium/src/common.cc
diff --git a/third_party/tcmalloc/chromium/src/common.cc b/third_party/tcmalloc/chromium/src/common.cc
index b92e988e56c0164c304f6210eb60bcc8769fcb8f..a35d1a1173368a7430f1b38d9847af1d5bc74854 100644
--- a/third_party/tcmalloc/chromium/src/common.cc
+++ b/third_party/tcmalloc/chromium/src/common.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2008, Google Inc.
+// Copyright (c) 2011, Google Inc.
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without
@@ -162,7 +162,7 @@ void SizeMap::Init() {
     if (sc <= 0 || sc >= kNumClasses) {
       CRASH("Bad size class %d for %" PRIuS "\n", sc, size);
     }
-    if (sc > 1 && size <= class_to_size_[sc-1]) {
+    if (sc > FIRST_SIZE_CLASS && size <= class_to_size_[sc-1]) {

[jar (doing other things), 2011/08/20 02:40:30]

The name seems bad, since it is actually the first usable, and not the first
size class (unless the code is changed much more).

Perhaps:
FIRST_USABLE_SIZE_CLASS

For completeness, you may as well add something to test the low values, such as:
if (AVOID_8_BYTE_CLASSES &&
    (sc == FIRST_USABLE_SIZE_CLASS) == (size <= 16))
   CRASH(...)

Then again.. they didn't have tests for this... so it is your call.

[bxx, 2011/08/24 00:19:24]

Done.

       CRASH("Allocating unnecessarily large class %d for %" PRIuS
             "\n", sc, size);
     }